The AM Forum

Finally got the third 40M Yagi up and connected up the phasing lines.  I made some notes that I will post here as I progressed through the initial tests yesterday and last night. 

I used a reference dipole at 45' high to compare against the 2x2x2 stack into Europe. I saw some very surprising results, including some early false disappointments.

Lots more tests to be run.

The three Yagi heights are:  190', 125' and 60' high, all fed in-phase for a take off angle of 13 degrees on the horizon, northeast to Europe. Full size elements, each Yagi weighs 250 pounds, reflectors = 70' long, driven els = 65'.   No high angle on model or experienced in operation.


Tom, K1JJ

Included are some shots of the 75M two element delta loops at 190'. Look carefully to see the wires hanging off the boom. This has relays that make it switchable to USA, NE or SW using a coaxial stub across an inductor to tune the reflector.  The two 5el Yagis below the delta loops are the homebrewed, stacked 60' boom 20M Yagis.

More shots.   Notes to follow about performance tests.

Really nice installation Tom!  How are you feeding them in phase?  What kind of combining arrangement are you using?

73,  Jack, W9GT

Here's some notes I made of emails to Steve, HUZ about the tests last night. I've included them here knowing other 40M enthusiasts will find them of interest...  ( I didn’t post Steve’s responses – didn’t axe his permission yet)

------------------

5PM Tuesday evening - 2 hours before sunset:

Steve,

Well, got it hooked up today.

I checked each Yagi using a 1/2 wavelength feedline. The Yagis are designed to be 50 ohms j0 on 7150.   They were all between 55 ohms to 60 ohms,  j10 or so.  Not bad at all.  They should combine nicely.

The resulting swr into the 50 ohm hardline line was about 40 ohms.   The doghouse 75 ohm hardline saw about 65 ohms or so.   So, the overall matches are decent.


At about 5PM, two hours before sunset I compared it against the low dipole at 45'.  To my surprise, the dipole was about 2 S-units louder on all Euro stations, including the BC stns!   I thought for sure something was wrong, like I reversed one of the driven elements feeds.  Later at about 6pm the dipole was still an S unit louder. I was yellafied.  Failure – Loser!

I was baffled cuz the f-b was very good on the USA stns, like 20-25db or more. The side rejection was also good down to S.A. like 30db at times.  But no forward gain.


I took Yaz for a walk and came back at sunset.  Now the two ants were equal. Looks like the angles started real high and were coming down.  I heard a 9K2MU  in Kuwait and he was about  8db louder on the 2x2x2!  The Euros were slowly starting to come up slightly on the stack too.

At about 9PM I came in and tried it again. It was like night and day.   I first heard a G4 who was S9 on the low dipole and 20 over on the stack!  I heard some 9K2's calling CQ and I could barely hear them on the dipole - they were S9 and actually loud on the stack. All the Euros were between 10-20db louder on the stack til about 9:30, present time.   It was now working as it should all along – all because the angles were now coming down rapidly.   


I also notice that the QSB is very fast on the stack. It's like a flashlight that must hit the right angle to really play - if the angle is off, the signal drops off big.  Some of the peaks were tremendous like 25db difference compared to the dipole, but short lived.  This shows the band has lots of variations. One night 13 degrees TO (the stack) will be favored big time and it will really play, I guess.


There appears to be no high angle on this stack at all, as the modeling shows. On some USA W4's they are +45 over on the SW wire Yagi and drop down to a watery sounding S5 on the stack. This is rare, but shows there are some rear lobe "tuck in" going on. 

I think I will need another wire Yagi NE at about 70' to cover the higher angles. This thing's TO is as low as a vertical will have a big gap at times. Can you imagine the low dipole being TWO S units louder than the stack before sunset? This shows they are really totally different antennas to see that much delta over the short band time I checked.   It appears the angles go from maybe 60 degrees down below 20 degrees as the sun sets.  I'll see what happens later tonight.

This is a one job antenna system, caw mawn.


T



Steve,

I'm not sure what happens to the angles in the winter on 40M.   At least the trend appears that nighttime is good for low angles.     I always thought when the D layer disappeared at sunset, the angles would be higher cuz of the higher layer, but not so.  During the day to Trons, the high antennas always were better. At night the lower ones worked best to Maine.

The past high angle VK thing on 40M must be similar to what I saw today.

Anyway, no, not on the air yet. I need to test the whole system for 1500w yet. Even the 75M relays haven't been given a test.  Any of this stuff cud blow out.

I have the 2x2x2 hardwired all in-phase.  I do have a WX0B switchbox and cud switch all the combos, but Chuck tells me that 95% of the time the all in-phase is the best. He had one on his 2x2 stack and later removed it.

We'll see how it plays over the next few days.  But I do need something to cover ~ 25-30 degrees TO like you have.  I don't want to be making excuses all the time like the vertical guys do about their low angles, etc.... :-)


To select only the lowest Yagi, the other Yagis in the stack have an effect on the pattern. It's not clean in the vert plane like using a single Yagi at 70'.  But when all are driven with the middle one 180 out, the pattern is quite nice at 30 degrees or so.  I COULD use a 180 degree coax line wid a relay. I'll do some modeling. It wud eliminate having to put up another wire Yagi maybe.  I’ll have to think about this some more.


T



Steve,

I just heard a guy from W2 say the band was acting "funny" tonight and cornditions were very poor.  The Italian stn he was working was S3 on the dipole and S9 on the stack.   Maybe he means the angles are low tonight and his dipole is high angle, dunno.  On the stack the band seemed hot…


At 10:30 I see the delta between the two is still as big as it was at 9:00PM. Still see 10-20db difference.  Great! I tuned in a bunch of BC stns all the way up to 7300 and see a good 15-20 db diff.  The 2el Yagis can go high in freq cuz the reflector keeps working. If it were a 3el, the dir wud screw it up above 7200 or so.


The stack seems more stable right now and the low dipole is fading badly. So guess the low angle stuff is taking over now.   That's good news for me... :-)


Anyway, all in all, it looks like this 2x2x2 may be one of the best systems I've ever put up. It's so optimized for one purpose it HAS to work when the cornditions are right.

T


Steve,

At 11:10PM:

The angles are dropping even more and the stack is becoming very  stable and loud.

The low dipole has deep fades and is PW.

I'm finding the f-b and side rejection is huge.  These low angles make it so.

I'm gonna hit the sack, but wud be curious to check this some time until morning to see what happens.


What a huge difference in cornditions between now and at 5PM earlier tonight.   I never wuda believed the angles changed that much.

T

--------------------


Steve,


Listening at 1:30AM in the early morning to 40M...

The biggest differences yet.   I hear western Eur with S1- S2 signals on the dipole with S9 on the stack. 

The VK's are almost the same strength on NE or SW Yagis, showing it's probably high angle from them still.

The angles stateside seemed to have risen, as the f-b on the stack is not as high as earlier.

The stack is performing something like the  5X5 on 20M -   big signals and fast fading showing it is very selective and narrow in the vert plane.

 
T


More tests to follow from tonight’s action…

Tom,
This sounds like a real cool interface into 3 SDR receivers and do phasing in software.
Or set up switching/phasing to select any combination of 1,2 or 3 antennas

I can listen for ya around 11 PM your time (6 AM my time) here in SV, Tommy.   I just have a 30' wire thrown into a tree so xmitting is prolly out of the question. 

What channel ya being on, caw mawn

Hi Jack,

All hardwired in-phase for now.  I may later try my Stackmatch which permits in phase, out of phase, upper alone, middle alone, lower alone, etc.  Though I like to keep it simple for durability and might make a lower wire Yagi at 70' to cover the higher angles into Eu. The higher angles certainly appear to be important at times.  For combining the Yagis, I just made them all about 50 ohms and tie the three RG-213 coaxes together. This gives 16 ohms. I then go into a 1/12 wavelength coaxial balun to bring it back to 50 ohms. This connects to a 50 ohm hardline run that's down the tower. At the doghouse I use a 50 > 75 ohm torroidal balun to go into the long underground run of 75 ohm hardline to the shack.  In the shack I deal with 75 ohms using a pi-network - no problem.



Frank:  The separate SDR RX would require a separate feedline run to the shack for each Yagi.  I now use about 550' of hardline for the run, so it wud be out of the question. I have other feedlines run, but they are for other antennas, like the bevs.


Johhny:  Glad to hear you're doing FB in Greece!  I don't expect to transmit with the stack for a few days yet.  I want to test a lot of stuff first and it can all be done on receiving. Also want to run a smoke test. Nothing worse than it stuff failing on the air cuz it was rushed.  I'll send ya an email when we get on. I think Huz will be joining us, as he's pretty active and wants to size up the latest competition... ;D

T

I have a US phone # here (HUZ has it) and can give you real time feedback OM as to how many pounds yer pushing.  Gimme a call when you're testing, I'm usually up before 6AM SV time.

Here's my response.

Drool .... slobber..... drool......duh, .......... nice antennas dude. I'm selling out and taking up stamp collecting!   ;D

Tom Vu,
You could mount 3 softrocks on the tower and convert down to 10 KHz and send audio back to the shack through 6 shielded pairs. And work some software magic.

There's a 1-lander doing that with a bunch of verticals. Makes some very sharp patterns with relatively little real estate. And he can steer it in almost any direction.

Interesting on the software steerable verticals, Steve. Which one-lander is doing that - on both 40 and 75m?

Yes, Frank, I wud imagine playing with phasing for just receive cud create a nice edge since angles appear to change so quickly on 40M - and by large amounts.  No wonder many of the guys here have been talking about signals dropping out quickly at times.

Though, this Softrock stuff wud be for receive only.  I wonder how they handle a lightning strike on the tower.... :o  I wonder if it's better to do it with simple phasing lines/torroids to include transmitting  side too.


One thing that has been bothering me - did I connect the inner coax lead to the same driven element side on all three Yagis? I remember doing it for two, I think, but the third one might have slipped by, dunno. There were months in-between each one's construction.  The only way to check it now is to put 9V on the coax on the ground and climb the tower with a DC meter. I'd need to reach out with a pair of long aluminum poles connected to the meter to touch both sides of the driven elements to make sure the polarity is the same on all three.   I wud think the performance wud be pretty poor for low angles if one was reversed, according to modeling, but it still haunts me. Gotta get up there and see. [And, if one IS wrong, it means unbolting it and spinning the boom vertical on up the tower to get at the connections - yikes]

T

Tom,
I've been looking for the link Huz talked about but can't seem to find it yet. I think he uses 4 receivers. I would put a relay on each input to disconnect the RX when power is off. One of the guys I work with  was flying last week and the plane was hit by lightning.

I was listening tonight on 40M.  SAME pattern. 

At 5PM, the low dipole was 2 S-units louder than the stack into Europe. It was like the stack was broken! Then they were about equal at 8PM, after sunset.  Then about 9PM the stack started to improve very quickly until now (9:30 PM) the stack is between 15-20 db louder than the dipole when listening to Germany. The dipole is very PW at times.

The big improvement happened very suddenly after 9PM, within a few minutes. Same pattern for the BC stations.

I'm still on the fence of whether to switch the stack or put up a new wire Yagi for the higher angles. I just might convert the low dipole into a higher angle wire Yagi for Europe.  Switching the stack with relays is somewhat undependable at best.


The modeling of the two antennas shows why there is such a big difference. It's much to do with the lack of high angle lobes on the stack - and the lack of low angle lobes on the low dipole.  The difference at 30 degrees T.O angle between them is easily 20-25db.

(Heard the HuzMan holding court on 7138.)


T

Aren't new antennas fun?  ;D

And do I know that sinking feeling at first when something doesn't seem right.  

>We'll see how it plays over the next few days.  But I do need something to cover ~ 25-30 degrees TO like you have.  I don't >want to be making excuses all the time like the vertical guys do about their low angles, etc.... :-)

I had some fun last night reading the mail on 75 with the vertical and the high band dipole both fed into the out-of-phase phase nulling box for a sort of diversity reception thing (I was too lazy to go hook up the low band dipole).  

Yes, 40 will change dramatically in a minute.  I've been in early evening cloud burner QSOs and poof everyone's gone like a switch got thrown.  In winter it'll happen around 5 or 6 p.m. local.


Rob

http://k1lt.com/

Here you go

Yep. That's the guy. I was just going to post it. Seems like it could be the ultimate receiving set up.


The softrocks are in the shack IIRC.

So does huz have the same problem with his loops?

Which problem is that?

Interesting approach this guy has for receiving antennas. After reading it over, my feeling is it uses too much hardware to accomplish directivity. I'd much rather do what W8JI does and that is use multiple terminated beverages in a circle and select the proper one with relays - that's it.

The patterns on some of the "steered " directions are not that clean, though usable with the 8 verticals.  I think a pair of phased beverages looks much better in the favored direction.

It does take up some room on 160M for spacing the verts apart.

It wud be a cool technology project to play with, but I'll stick wid simple beverages here.


BTW, I made up my mind to switch the 2x2x2 stack for higher angles. The modeling shows that by simply feeding the lower alone OR the lower and middle OR all three gives a nice, gradual selection of vertical angles - clean too. I'll make up a heavy duty relay box that keeps the bottom one on all the time and clicks in the middle and top Yagis one at a time. The swr will be as much as 2:1 with the lower Yagi alone, but I can live wid that.

I might even use my StackMatch, but doubt that can handle the abuse of AM operation...  ;D


As Franked axed, Steve, have you compared your loops against some other reference antenna and see a big difference in angles at 5PM vs: 10PM?   Maybe your loops are pretty much in the middle of the vert range and don't move around much, I dunno.
Frank, there's no problem, just that the angles need to be low for the stack to do its job, if that's what you mean.

T

drastic changes in performance as the time changes after dark

Tom give some thought to impedance transformation switching so you end up 1:1 in all three positions. Or am I getting sleepy. Been playing with my Daughter's new computer all night.

No. I haven't noticed anything like Tom has. I wouldn't expect to either. His antenna has a take-off angle that is much lower and the vertical lobe is much more narrow (compressed) too. His antenna is more like a laser beam. Mine is like a flash light with pissweak batteries.

I can work Europe easily well before dark - several hours on most days. A few weeks ago I worked several German stations at 5PM local. Both were over S9. I had two EU stations come in at 15-20 over 9 at 7PM ET tonight. Also worked a VK6 on the long path. There is usually a good peak in signals from EU about an hour before local sunset and again close to EU sunrise. But good signals can be heard throughout the night. I'm guessing 40 might be open to EU almost around the clock in the winter.

Tom, that high angle killed us in DX contests until I put the 2nd 4 el 40 down at 50' and used lower/upper/both switching. We discussed that at Nearfest.

The same thing happens on 160/80 also.

Now what you really need to do is put one amp on each antenna and have a voting system for receive ;D Or the phased Beverages.

Carl
KM1H

Frank,

How would you go about doing this with the minimum hardware?  Relays and coax or relays and torroidal transformers?


1) It would be nice to do lower alone, lower and middle in phase - and all three in phase. (3 selections)


2) OR keep them all in phase and just put the lower out of phase with the rest - and the upper out of phase with the rest. (2 selections)

At this point it's hard to say which ones are most useful. Putting the bottom out of phase with the rest results in a strong 60 degree TO angle.  Making the top out gives a strong 30 degree angle. That's with all three working. If I do just the lower, etc, the gain is reduced.  All three in phase give a 13 degree T.O., very low.
 

I have a WX0B Stackmatch I plan to try, but it is fragile and does not have 180 out in it unless I buy an expensive add-on.  These boxes cost too much for what is in them.

T

let me think about it after a good night's sleep. I'll day dream while writing this stupid procedure I need to finish today.

Tom, if you have access to the NCJ or Scuttlebutt that should be covered in detail many times over the years.

Id suggest just relays as they are a miniscule part of the phasing path at that frequency. Coax will have no measurable effect on phasing or bandwidth if cut right. 

Do the combinations as elaborate as possible at first until you get a feel for what works best and then simplify.

Carl
KM1H

I just sent you a schematic with 3 relays to select 1, 2 or 3 antennas.
You will need a 1:2 splitter for 2 antenna operation. I assume bottom antenna for 1 , two top antennas for 2 and then all 3

Tnx for the drawing, Frank. I'll have to think out what I need to do.


Yep, I screwed up. As a phasing test, I put 9 volts on the coax and climbed the tower to see if the element halves have + voltage on the same side. (all in phase)  I figured it was a waste of time, but wanted to be absolutely sure. Wouldn't you know it - I spaced out and the middle Yagi had the inner conductor connected to the opposite side as the other two. The middle is 180 degrees out of phase compared to the others! Yikes.  The pattern models out to look rather poor. I cannot understand how it works so well for low angle.  It has a HUGE lobe at 60 degrees and a small one at 13 degrees.

Anyway, to fix it I can either spin the boom vertically on the tower and swap the leads - a rather risky operation for one guy - or, I can remove 45' of coax (1/2 wavelength) from the coiled hank going to the middle Yagi to get it back in phase wid the others.

Either way, the matches will change and I'll need to spend time dicking with that again up on the tower.  The other day I wondered why I had a different match reading than the model showed when I put the three feedlines together. When measured individually, they were about 55 ohms, but when put together, the out of phase Yagi has a huge effect on the others. Now I know why.


So, back to square one wid the testing tmw... cheez.  The bright side is that hopefully the system will work even better for the low angle stuff. Probably less fading than what I saw before cuz the lowest lobe will be MUCH fatter since the lobe at 60 degrees will be gone and pushed down into the 13 degree lobe - once they're all in phase..

T

Fun and games Tom eh, you certainly have my sympathy; this kind of thing makes you want to cry, it does me at least.  On a much smaller scale I about killed myself getting one of the masts up and had a pulley bind up on me raising the big dipole feedpoint; I had a second one up there with a rope through it (thank heavens) so I abandoned the binding one and put the feedpoint and one of the short dipole ends on one pulley.

But back to ur yagis--I wonder if the fast QSB you observed was due to phase cancellation from the same sig arriving at high and low angles and battling with itself.  Sort of like what you get on FM bc band when an airplane flies overhead.

Rob

Tom,
I always mark the hot side of the coax on any antenna I build. Try putting some tape on the hot side element so you can see it from the ground.

Yep, I shud have taken some precautions. I just figured I'd make all the north elements the hot side as I usually do.  It's just that I wasn't paying close attention on the second Yagi and it got by.  I had a 50-50 chance of getting it right, but gambled and lost... :-)  Tmw I'm determined to go up there and spin the boom and fix it.

Rob,
That's a good idea to have two pulleys set up when there are critical situations where you don't want to take it down. You lucked out having that extra feedpoint pulley... :-)

I think fading is two-fold in this situation. Yes, the cancelation of two arriving signal paths is one reason to fade. Another may be when there is a very narrow and compressed vertical lobe (like the stack) and the ionosphere keeps changing. It favors the low angle at times, then changes so that the low angle is not favored. It's like a boiling mass of mirror glass that randomly changes, but still has a major trend as the night progresses.  That's why a stack is used to fatten up the antenna's lowest lobe as it robs energy from the higher lobes. If you're gonna play the low lobe game, might as well have it all down there and make if as broad as possible to accomodate the changing low angles. Use another antenna for the higher angle stuff or switch the stack around.

T

Let's hope when you get the middle one flipped the fast QSB goes away along with the 60 degree signals and it's all nice smooth loooooooow stuff.

Spent 4 HOT hours up on the tower today and spun the boom vertically and reversed the coax connections on the middle Yagi. What a job at 125' high manhandling a 250 pounder!  Now they're all in-phase for sure.  The match is now much better - about 58 ohms +j0 at 7150 after the combiner.   I came in at 2:30PM  and listened to the band. I can now hear many Arabian BC stations above 7200. On the dipole they are barely copy-able at times. Maybe a 10-20db difference.  Before the fix, never heard any difference compared to the dipole in the day.

Before the coax fix I was listening to a 60 degree TO angle  with some 13 degree mixed in - no wonder the signals were PW before sunset.

Anyway, the band sounds much busier into Europe during the afternoon and the f-b on the stack to USA is as much as 25-30db++ on certain W4's.  Think it's working FB now - just gotta make up that 4-position splitter/combiner to select the higher angles.


It was worth fixing the Yagi right - now they all have the same coax lengths  - dead accurate and sure for future add-ons.


** Update at 4 PM:  I'm hearing EA4's from Spain coming thru. They are the same strength on the low dipole as the stack.  Looks like closer in western Europe  is still higher angle propagation maybe until local sunset..  The Arabian stations are still 10-20db louder on the stack, showing low angles from them.

T

as long as you can hear the black james bond, everything will be ok, Tom.  ::)

You will be off the side Derb and PW so you better  QRO OM.

Update 5:30PM:

I hear an ON4 from Belgium.  He is about 2 S-Units louder on the STACK compared to the low dipole.  This is much earlier for western Europe to be louder on the stack - compared to before.

Maybe the late sfternoon/early evening angles were low all along. Just that the stack was broken.  I'll listen again in a coupla hours.

Hopefully the low 13 degree angle is useful much of the time into Eu - we'll see.


** Update 5:40PM:   Taking an average of six Euro stations, they are all about 12+ db or more louder on the stack. It's a good 1 1/2 hours before sunset. This is a good sign!

I'm hearing lots of noise coming from the Northeast, like a storm in the Atlantic. It's at least 15db noisier NE than SW tonight.

Certain USA stations (W4's esp) are NOT copy-able off the back of the stack, while  S9+15 on the SW Yagi.  As the model predicted, the f-b has improved further. Stacked 2el Yagis exhibit a certain "curtain" effect which improves f-b markedly compared to a single 2el beam.

T

8:15 Update:

The sun has set 30 minutes ago and many Euros coming in. The noise is still louder to the NE by about 15db. Probably thunderstorms in the Atlantic.

I've heard the biggest difference to date tonight.  I am getting 20db advantage on the stack easily over the low dipole. It's not a fair comparison, but it IS a comparison since the beginning of testing.   The stack is VERY stable in comparison to the fading dipole. I think that single low, fat lobe is starting to pay off.

I heard an SV1 in Greece calling CQ. I dropped my power down to 10 watts and gave him a call on the stack. He came right back and gave a "59"... :-)  First contact.

The receive difference over the low dipole is so striking now, I am satisfied the stack is working FB. It's time to fire up the amplifier and try holding court over the next few days.

The next project is to add the splitter and relays on the tower at 125' to select the lower, lower & middle, or all three.  This will progressively lower the angle from beginning at 30 degrees down to 13 degrees. 


Does anyone know of a source for those open frame 24vdc  relays that are about 2" X 2" X2"?  I think they were used in furnaces. They make good RF relays - I need about five or so.

T

I like P&B DPDT 25 amp contacts used in machines.

JJ was WHIRL WIDE on 40 meters tonight. He kicked my a$$, not surprisingly. He was heard in Indonesia and easily worked Iraq when no other NA stations could hear the YI1RZ.

That stack is killer!

Yeah, Steve, what a blast we had last night! Even the Tron/HLR joined in with us for a while working the Euros.  The pileup was thick and deep for most of the night.

Nothing like trying out a new antenna for the first time.

We worked quite a few old friends and some rare ones. I’m still floored to have worked Iraq for the first time, ever. He was running 100w into a vertical with radials over sand. Said he was always losing power cuz of the 2 hour interruptions – rolling blackouts.  I could not hear him on the dipole at all, but he was clear and S9+20 on the stack.  A long trip like that is when the low angle really pays off. I held him on freq for 20 minutes looking for North Americans to work him, but cornditions did not permit it.. It would normally have been a riot if he was stronger.

Here’s a list of the stations we worked. Many we spent time chatting with. HUZ you were kicking ass wid those delta loops and bevs, caw mawn.


Worked:
G0SGX
GI4PDX
SH8IP
DL2VF
UT5DA
HB9EOU
ER4DX
EC8AIQ
Ei6S
EN8ARG
9K2CQ (Kuwait)
PI4AMF
PR7AE (Brazil)
CN8ZG
G4ZCG
RA3HCL (Russia)
IT9VPT
RN6FJ
SM0XBI
CN8WL
GW6LHF
M3YWH
403A
HB9JC
G6ZBC
LA1WHG
RW3GJ
YI1RZ (Iraq)
RZ6UY
M3TGC
UT4CDO
RA3PET
LZ1QI
RA3PET
SQ7HTK
EC8OJ
DA1AF
Spotted by YC1 in Indonesia on DX cluster
UA1JS (Hiram)

What a great time!

Tom, K1JJ

The low angles really seemed to dominate. You always seemed to hear the DX stations much better than I could. When stations were a solid 5/9 at my place, you were hearing them 15-20 dB over 9.

Amazing.

I'm sure tom is hearing very well but he does have a unique way of calibrating his S-meter.  ;D

old habits die hard Jay.

Yes, of course, glasshoppa...   Let me give us a "seat of the pants" S-meter calibration lesson...  ;)

To calibrate my S-meter, I pick a night when cornditions are excellent and the 40M BC stations are just crashing in. I then pick the strongest one I can find, like Radio Moscow, etc.  I then calibrate my S-meter so that the station is JUST pinning the meter at +60 over.   Might as well use a reference that is real whirl and uses the full range of the S-meter.

Anyway, when a ham station from Europe is 40 over that means they are within 20 db of the strongest megawatt/curtain array  BC station I can find, etc. Last night one or two DX ham stations hit 45-50 over. That's really doing something for an amateur station!  (ER4DX in Russia and EI6S in Ireland did)  The 50uv= S9 standard, or whatever it is, means nothing to me.   If I run across a newer station that pins the meter past 60 over, I will back down the meter again.

This also makes the DX stations feel good to get big reports. Since it's all relative anyway, they can listen to what others get and know where they stand, no matter how the meter is calibrated.

In contrast, I've heard guys with so called "Scotch" S-meters giving out the strongest stations S7, S8, etc. In this day and age of instant gratification and bling, the DX wonders what is wrong with the receiver or their own signal.

That's my take on it in a nutshell.

The bottom line  is how well can you hear the DX?  No one can hide using extreme QRO, the latest ricebox, etc if they can't hear - no matter what S-meter report they give out. That evens out the playing field and makes it fair, in a way... ;D

T

Didn't you say I was 60-over on your meter one time?  Just call me VOA. I would have said BBC but one of the EU stations used that description for your signal last night.

Yes, definately. You are constantly pushing 50-60 over here on 40M when the high angle cornditions peak. Last night you hit 50 over but later dropped down to S8 as the low angle took over.

What I don't understand is when I listen to other W4's from your area, they are usually nowhere near that loud here or in Europe. I think you have those delta loops at the perfect height for both New England and Europe, depending on cornditions.  If you ever put up that tower and Yagi, I wud keep that system as a reference and fill-in.

Frank is talking about putting up a similar one too. Were you gonna publish the details here at one time?

T

It's my secret weapon. I cannot let it out in the wild.    :D

It's pretty simple really. Just make two full-wave loops and space them 20 feet apart. Feed one and place a shorted coax stub on the other. Cut the stub for best F/B. Make it switchable with some relays. I'll post details this evening.

You may a been 60 over, but Tommy told me he used me to reset his S-meter as "the standard".  Remember, when I get on 40 the QRM clears out  ;D

I'll listen for youse gangstas this AM (about 11 PM ur time).

LOL!

Yes, as it was once said, "When W3JN came on, the QRM QSYed."

Geeesh you guys.  Now its even harder for us nines to get thru the east coast curtain.  Still hav'in lots o' fun work'in into Europe and the Middle East.

Steve, I only have one full wave loop, but it sure works better than a dipole!  I'm working on putting up a second loop.  Look out you guys....I may then only be 20 dB down.  :o ;D

73,  Jack, W9GT

I heard you in there one night working some DX. You were doing very well. I know you were loud at my place!

That second loop will improve your hearing markedly once the atmospheric noise if gone from a whole hemisphere. Really worth the effort!

Yep, you should join us when we all hold court, Jack!  It wud be fun to have a midwestern station with us to give us some more DX come-hither. The Euros do it all the time - why not us?   We had some real good times in the past on 75M with an "American group" working DX.  Like a gang bang, we'd all work over any new call-ins...  ;D

As you know, the DX stations can usually hear most anyone in the USA, especially the big gun foreign DXers. But hearing the weaker DX takes a good beverage, K9AY or excellent transmitting antenna. Nothin's more embarassing than getting an S9+20 report and not being able to copy it.... :o   According to some UK hams I talk with, they claim the USA has a reputation for having no ears.  We gotta fix that... ;D

Johhny/JN - I hope to get on 40M tonight. We'll make a special good guy radio "dedication " to you.   

T

;D :D :P roflcopter

Yea, we pass them around like a cheap date -- just like G4AMN and the UK crew do when we call them on 3799.

I double down DARE you to call " CQ DX gangbang, calling CQ CQ CQ for a DX gangbang " tonight.

toss em around like a chef salad.  :P ;D

Yep, and the "radio climax" is getting your signal report.... squeeee... ;D  There are some parallels.


It reminds me of the movie scene in Star Trek where "Voyja" was looking for it's maker, its code. Spock entered in the code and all hell broke loose.  Likewise, hams look for a hot romp when they call over and over until they finally get that report fix. After that, it's time for a cigarette.

Occassionally we call our beaks out but go home with nothing
T

but what is 60 over in real volts. Like adding zeros to dollar bills and trying to pass them

No not quite. It's more like locating the baddest MoFo on the playground and daring anyone to try to kick his ass.... ;D

[Next chance I get I'll run a sig gen into the FT-1000D and let ya know, Frank. It's probably not far off from your own receiver.]

T

Volts are ambiguous. The amount will vary with the antenna connected. Field strength would be much more useful. But best of all is SNR. Of course that will vary with the antenna used too.

Well, I just ran an S-meter test using my RF signal generator into both the FT-102 and the FT-1000D. I used a scope to measure the signal levels while under load into the receiver.

Both radio S-meters were previously set using the JJ Radio Moscow full scale method.   I will need a hi hi FB better generator and measuring gear to get better accuracy, but this is OK for now. [Frank, bring your HP with you next time you stop by)

At 50mv, (supposedly +60db over 9) on the FT-102, I found the S-meter was reading +55db over. About 5 db low.

But on the FT-1000D, I found the S-meter was a little high at about 66 db over S9. Not bad at all, really.

At 50 uv, testing S9, I didn't like the scope accuracy, so let that measurement go for now...

I understand that some of the ricebox manufacturers make their S-meter circuits generous, to give out better reports. I dunno. Has anyone run tests to check linearity and absolute S-meter levels?


Posted below are the S-meter levels you shud see at various voltage levels. All in all, I still prefer to set my meter at full scale to Radio Moscow and let the mud ducks fight to hit that standard, caw mawn.  If I want a "true" S-meter reading, it's simple enuff to add in 6db of attenuation from the rig's front panel . No big deal.

T

S-points for frequencies below 30 MHz:
Signal
strength   Relative
intensity   Received
voltage   Received power
(Zc = 50 Ohm)
S1   -48 dB   0.20 uV   -14 dBuV   790 aW   -121 dBm
S2   -42 dB   0.40 uV   -8 dBuV   3.2 fW   -115 dBm
S3   -36 dB   0.79 uV   -2 dBuV   13 fW   -109 dBm
S4   -30 dB   1.6 uV   4 dBuV   50 fW   -103 dBm
S5   -24 dB   3.2 uV   10 dBuV   200 fW   -97 dBm
S6   -18 dB   6.3 uV   16 dBuV   790 fW   -91 dBm
S7   -12 dB   13 uV   22 dBuV   3.2 pW   -85 dBm
S8   -6 dB   25 uV   28 dBuV   13 pW   -79 dBm
S9   0 dB   50 uV   34 dBuV   50 pW   -73 dBm
S9+10   10 dB   160 uV   44 dBuV   500 pW   -63 dBm
S9+20   20 dB   500 uV   54 dBuV   5.0 nW   -53 dBm
S9+30   30 dB   1.6 mV   64 dBuV   50 nW   -43 dBm
S9+40   40 dB   5.0 mV   74 dBuV   500 nW   -33 dBm
S9+50   50 dB   16 mV   84 dBuV   5.0 uW   -23 dBm
S9+60   60 dB   50 mV   94 dBuV   50 uW   -13 dBm

The only accurate S meters in my shack are the TCI / BR 8174 and HPSDR both track the  signal generator within a dB. Holding that kind of tracking in an analog AGC would be tuff. The R390A tracks quite well but the settings drift around a bit.
HUZ is right it is all about signal to noise ratio.

Heard the HUZman on 7160 a few minutes ago, but Tom was either not on or too weak to copy  ???

We were on 7156 until a little after 11 PM ET - 6 AM your time. You must have heard me working the ZS on 7160. I shut down after that. I didn't have to, I just did.

I wouldn't be surprised if the US-no ears rap is true and due to the importation of all manner of unshielded unfiltered RFI producing cheap junk here.  I may be mistaken but I would not be at all surprised if I learned the EU has much more stringent spectral purity requirements for unintentional radiators, such as no unintentional RF emission.

I'll be the first to admit I have no ears on 160 and 75.   I don't even call CQ on 160 because I know I get out a lot better than I can hear through my S9 noise level.   I badly need to put up some kind of rx loop antenna.

>I understand that some of the ricebox manufacturers make their S-meter circuits generous, to give out better reports. I >dunno.  Has anyone run tests to check linearity and absolute S-meter levels?

That sure doesn't seem to be the case with my 1000MP Mk V.   It seems to have the most stingy S meter I have seen.  It's a bit embarrassing because I almost always get better sig. reports than I can honestly give. 

I have considered using the Wolfman Jack wx conditions approach to sig reports:  Ur 260 dB over 9 here OM!

73
Rob K5UJ

BTW, I like the idea of scrapping S units entirely and simply having meters graduated in dB from 0 to some upper limit.  Why not simply have that and a standard manufacturers can all meet and do away with the S unit nonsense?

R.

Aw, too bad - you must have just missed me, Johnny.

I made TWO radio dedications to you and told the DXers we were waiting for you to get your local govt's permission to get on. Talked to a guy on Crete and Huz mentioned you in Athens, etc.  The SV9 was hitting +35 at times, so I KNOW you can make it thru to us, even with a modest wire hanging out.

We both worked a good 35 stations again including lots of Russians and some S. America for a change. It was fun to rule the court session with an iron fist. We would say, "OK, stand by Europe... we're switching antennas to S. America now - click."  And sure enuff, a few S.A. stations had been patiently waiting and came back to us. Then back to Euro and they came at us again.  The HUZman and I are having a ball!

T

Glad you guys are having fun... I'm stuck with the exact antithesis of your ant, Tom, a 30' length of wire tossed into a tree, about 6' from the wall of the apt building.

I'll listen again tomorrow AM ifn I get my raggedy ass outta bed in time.

I guess in some parts of the USA we deal with BPL. It's still around???? But Rob, in other countries THEY deal with horrendous line noise from their electrical system. Beverages and loops and ewes are a mainstay for their ears.

And I thought a standard for setting the S-meter was 50 micro-volts for S-9

Fred

If there's not too much static tonight, I'll probably be on. My ears took a beating the last two night with JJ picking out the pissweakers. Lots of static from some storms in the Atlantic and last night additional storms in FL and other parts of SE USA.

I'd like to get on too, stadick or no stadick.

We should think up some new routines as we hold court. I think it's time to listen for "Russian stations named Vlad who drive yellow Yugos with wives named Svetlana or Olga.... only please!"

Also try to get some more PW 10W UK stations. The one we worked last night almost blew a cork with joy - man, he was excited.  Another one I use is to listen for any station who has NOT worked North America on 40M yet. That call actually pulls out quite a few pissweakers who have about given up after being body-slammed too many times by the I's and EA's for way too long.... ;D

I notice the real action starts after 10PM into 11PM est as the Russians and Europe wakes up. Earlier, we are talking to the insomniacs.

T

There are two peaks in activity. One is early 6-8 PM ET (maybe even earlier now as the days grow shorter). These are the late nighters in Europe. There is also a propagation peak due to our sunet. Also, early on your will get some VK and ZL action on the long path. Other OC stuff may be available too.

Then there is a little lull as most of Europe goes to bed and the early risers aren't up yet. But around 11 PM ET, the Russians start to show up (it's something like 0500 their time). A little later the EU early risers show up. Another peak in propagation occurs with the EU sunrise. Right around that time, 1AM ET or so, ZLs start coming through. An hour or so later, the VKs (mostly VK7s) start to come through. Closer to our sine rise, more VKs (1,2,3) start to show up.

Of course, Central and South America is available all throughout these times, but I hear much more out of Europe.

So, you can work DX on 40 meters right now from about 4-5 PM ET to about 7-8 AM ET. With a better antenna you can add an hour or two on each end of these time. I would imagine this winter it will be around the clock or nearly so.

Is this cool or what?  First Iraqi contact - ever - the other day - and confirmed on 40M. Love that eQSL.   I'm sqeeeeeing all over the stack.... ;D

T

I hope you don't work him more than once!     ;)

Listening to you guys holding court now.

Tommy:  S9 to s9+10
HUZ  S6-S7
W1TR S3

No QSB to speak of and no lightning static here OMs

I listened in for a while around 9:30 PM last night. I even heard that 10 watt Russian good enuf to work. You were S8 backwards most of the time, Tom.

Yo Johnny -

Glad you tuned us in. Yeah, we can probably work you once you get something running. That oughta be cool, like working a spy outpost.... :-)

Chuck / K1KW joined us too. He attracts lots of old friends, both local and DX break-ins. It became quite a party when Nick, LZ1JY broke in with about five of us stateside.

Buddly: You're hearing pretty well out there to hear that 10W Russian. What were you using? 

Huzman gets the award for hearing the weak ones last night. There were times when he was picking out stuff that us NE guys were struggling with. I think it's partly his good location, but mostly the receiving skills he's developed over the last few years. He can pull stuff outa the heavy staic crashes like nobody's business.... :-)

T

I was using the 160M inverted L (125' wire) tuned to 40 meters.

I tried giving a call, but 20 watts or so into that crappy ant wasn't going anywhere.  Who knows what the SWRs are; the final was folding back and that's all I could squeeze out of the ToughShit-50.

That HUZ was only a few S-units behind you is quite a message!   I'm sure if I had something better you'd be pinning the guess meter, Tom.

I've been following the thread and I listened last night from Naknek, Alaska....No static and clear freqs, but problems with the BFO on the old HQ 129x kept me from hearing the SSB....Antenna is a 50 ft sloper.  I will hook up the FT 101 and try again tonight...Great stuff...Steve

O yeah, the Huzman is getting dangerous. There is talk up here in New England of forming a posse to take his ants out. He's embarrasing too many Northeast big guns... ;D

To work you, we will need to take a special listen with no others calling. When the loud I's, EA's and other Euros call, it's bedlam.  In fact, I listened many times for Russia-only and western Europe kept on calling anyway.  I was told by a friend in Israel via email that there were as many as 20 Russians calling, many from Asiatic Russia.  Even the closer Russians can cover up the very PW Asiatic ones.  

The only alternative is to give out fast 59-chow - 59 chow reports, but I don't want to resort to that BS.

Get your antenna / tuner set up so it takes power and we'll give it a try. Pick a specific time and we'll call for you, OM. 

T

Give us a call Steve. I've worked a few Alaskan stations on 40 but it would be fun to work you.

I'm still waiting for my sea freight (and my car, incidentally) which has the tooner, ant stuff, parts, amp, etc.  All I have is the Kennywood TS-50 I sent to myself in the APO mail.

I five fingered 10' of RG-59 out of the trash at work, and the ground is tied to the balcony raling with a twist-tie.  Not sure I can polish that turd, Tom, but I get up about 6AM anyway so I'll take a listen again tomorrow AM.

As long as the turd takes power and doesn't flush down the toilet, we'll hear you.... ;D

Send me your Greecian formula email adr to:  [my call]@comcast.net.

T

Good observations Steve.  I usually get in there for the first round, but unfortunately the second wave comes after my bedtime.  Have to get up early in the morning for work.  Anyway....seems like 40 M has become the prime DX band.  Sure lots of fun hearing all those Europeans and such goodies as 9K2CQ, 7Z4CQ, and 5N0OCH as well as many VKs coming through quite nicely.  Almost sounds like 20 M sometimes.

I'm working on a scheme to get a second full wave loop up utilizing some PVC pipe supported by some guy ropes and hoisted up to the 75' or so level on the tower.  I plan to do the same thing that you are doing...that is switching in a stub to add to the length for the reflector or switching out to look like a director.  Essentially will look like a two element 40 M quad.  Should work out well, since the single loop really works FB.

73,  Jack, W9GT

Very nice on the antenna! Can't wait to hear it. Look out Tom. Us guys with the loops are gonna take over!

I hadn't heard the 5N. Musta been on Charlie Whiskey.

BTW Jack, the first wave will keep getting earlier as the days grow shorter. And you can always work the VKs in the morning our time, if you have a few minutes before you have to launch out for work. JJ is always QRT that time of day, so we can have the band to ourselves!  ;D

Jack,

From modeling experience I've found that a director works very poorly compared to a reflector for front to back. (for 2el loops)  It is better to switch the feedline to the opposite loop and make the other a reflector only.

I did this same configuration on my 75M delta loops and they work FB.   Since f-b is vitally important, I would give it some consideration.  

I'd be curious if anyone has the same results when modeling a 2el loop with a director only.  I've found the f-b to be down around 12db? as a director vs: up to 25db when used as a reflector. (While maintaining reasonable input impedances > 30 ohms)

T

DE / Director has lower FB ratio I found on my old Quad. I did this on 20 meters and DE / Reflector on higher bands.

I agree with Tom. G6XN sez the same thing.

The switching is no more difficult if you do what I'm doing - two identical loops, both have with equal lengths of coax connected. One coax is fed (this is the driven loop), the other is shorted, thus placing an inductive reactance at the feedpoint of the second loop turning it into a reflector. To switch directions, just  unshort (is that a word) and feed the coax that was previously shorted and short the one that was previously fed. You could also use open coax stubs if cut to the proper length.

I'll run some models tonight for fun.

Yeah, he was on CW last night......one call & received 599, of course everyone was getting 599.  ;D

Yes, Tom...I will try it both ways....can experiment with configuration and see what works best.  It would also be interesting to see if you could feed both elements....vary the phase relationship...and perhaps steer the pattern to some degree.  Food for thought anyway.  It's not too convenient to physically rotate such a beast.  That might be an interesting approach for you to use on your 75 M loops.

73,  Jack, W9GT

Feeding both as a phased array will likely give you a slightly better pattern, mostly better F/B, but no more gain. It would also be more complicated to feed and adjust. No steering would be possible, other than moving around the null on the back side. This might help on receive if you had a noise source from a constant direction. But there are easier ways to do this with receiving antennas.

Yep, agreed!  The stub switching is the best way to go.



Check out this U-tube video of Huzman working Turkey on 40M, (To get it archived on this thread too)

http://www.youtube.com/watch?v=TvrMV6q5Lhs

Huz you are strapping tonight on the 75 meter dipole.
I5 station was weak though

Yea, that was I5REA. He was probably 10-15 dB down from his normal signal. Things were good for USA though. Jack/GT and I spoke for a while. At times he was 40-over! A 1-lander broke running 7 Watts and an 8 foot loop on the ground was 10 over. Mike, KA0ARA from KC also stopped by. He was 10-15 over.

An hour or so earlier, signals were booming in from EU. ON4BW was 20-over. Things change on 40!

I have been following this thread with interest and envy at you folks making big signals on 40M. I do wonder though if you folks with the big 40m signals into Europe have experimented with running AM, and calling CQ AM?  ;D

Last spring when I got on 7160 a few times running AM, I got quite a bit of talk over from angry SSB operators. I recall the day when 7160 was owned by AM operators (W5PYT, W5MEU just to name two).

Jim
WD5JKO

OE5MSM/Mike and I had a great chat last nite around 7160Khz. He was +10 for most of the 45 minute qso. Aruba P41USA, Bob was pounding in on 7149Khz and we chatted for a moment.

This darn summer cold got the best of me and I turned in early.

Fun days on 40!

Steve...you were also 40 over here! Very good conditions... earlier worked a few Europeans and signals seemed quite good.  Seemed like no effort required to get through to anyone I called.   Had to QRT to attend to a plumbing problem in the kitchen.  WA1UIL was doing quite well for using that magnetic loop antenna.  I thought he was running a hundred watts though.  Anyway,  sure enjoyed the visit and nice QSO.   I will be hanging out on 40 M more in the future to enjoy the great conditions.  Hopefully, will get a chance to work on the second loop this weekend.
While you guys are able to "hold court" would be fun to crank up the AM rig and see how we do into Europe as well.

73,  Jack, W9GT

We've had tons of AM QSOs on 7160 or so since March.

I've called CQ AM for Europe numerous times but no responses. I did work 9H1ES - Fortunato in Malta when he called CQ a few months ago. He was running his BC-610. He's one of the regulars on 3705 kHz along with F6AQK - Jean. I suspect we will hear more of the EU AM crowd this winter.

Very JS 2 dipoles 20 feet apart hanging off a rope. Force fed on 40 tonight first QSO's lots of fun. Next step build a boom for the tower and increase the height another 15 feet.. Solid 2 s units flipping the pattern at ON7TQ RX and TX.

Awesome. So ultimately, you'll have them at 65 feet?

Within a foot or so. Tom thinks I should put a guy wire above it supporting the ends. This will take up a foot or two above the boom. I'm using 2 inch thick wall 6061 T6 tubing 20 feet long and have some nice commecical grade clamps 1/4 inch thick steel. Last weekend bought all the SS hardware so just need to find a hunk of guy cable. I think I have a little left from the last toweer rebuild. I hope to build the boom Saturday AM. I hope to get it in the air sometime this weekend between the 9 other things that need doing. The boom will point 30 degrees north of East bolted to one face. Looks like the trees in the yard line up so ends will be around 50 feet.

Have you considered using one of those vaulting poles?

TIGHT !!  :o


Frank,

2" is not really that big of a diameter. Without trussing, it will probably sag 1-2' once you pull down on and tighten up the inv vees anyway.  Plus you have coax coming from each dipole to the tower with a balun and ferrite sleeves at the feedpoints. Plus ice... yikes.

When the next ice storm comes, you will be happy you have overhead trussing. Also, remember what I said about the mechanical advantage produced by overhead trussing vs: just bolted to the tower at the middle of the boom.  Picture a hurricane and the boom is bolted to the tower in the middle. Then add guy cables to each end pulled up and attached on the tower. Which one has more up and down rocking control and puts less force on the tower?
The extra 1-2' lost in height will not be seen on any S-meter. In fact, it will help your dipoles become flatter.  50' on the ends makes a good dipole apex angle. Shud work really FB.


BTW, a 40 degree heading is just fine. It will better favor the Russians in Moscow, Asiatic Russia, etc. Also India is farther north, about 30 degrees.  I have my Yagi stack beaming about 40 degrees too and am happy with the coverage. I even find the Swedish and Finns to be within the main lobe.  However, the Moroccan stations (N. Africa) at 75 degrees are way down, about equal to the low dipole.

T

Yea, I know but it is only 10 feet radius. I'll have room for the cable since the log is only about 2 feet above the top of the tower. I'll check home cheapo if I need some cable but I think there is some in the basement.
Pole is a good idea and we can dream about working the vaulter
 

She don't look Polish :o

Tom, the pipe is at least 1/8 inch. Anyway I found a bunch of guy cable 3/16 & 1/4
inch. Plenty of clamps some dead ends. I thought I had some of those thinble things to protect the ends but have not located any yet. I guess I could use SS tubing and bend it. Brake line might work. I only need 3 or 4 of them so I'll work something out. no fun being PW but nice to see the RX S meter change when the pattern is flipped. I'm running out of excuses.
HUZ you really strap.

When you get that thing to full height, I'm gonna be in trouble.  {Come on trees, grow faster!}

This  pole design is cut a little fuller.

store a little energy in that pole

Looking for suggestions....

I'm finally getting around to switching the 40M Yagis.   But I'm confused what to make of the impedances when I switch the top Yagi  (of three)  180 out.  180 out of phase on the top Yagi gives a single lobe at 30 degrees.

However, the impedances almost halve on the top two. So, the swr will be high on them and cause an unwanted phase shift, no?


Here's the impedances when all in phase according to modeling - in the real world I see about the same on the MFJ-259B:

44.4 + j5.7  bottom
56 + j1.6  middle
40.8 +j6.9  top
OK-fine



But modeling shows when the top is 180 degrees out:

50.5 +j4  bott
33 + j10.6  mid
24 +j 14.9 top

Since I can't match these at the feedpoint for each Yagi on the fly, I am stuck with this swr on the upper two when 180 out.   Should I just feed them as-is with the extra 180 degree coax attached to the top Yagi or will I have intolerable phase shift that will cause pattern problems?

I could add or subtract coax to each Yagi to compensate, but that wud make the switching way to complex. I already need 7 relays to do the complete job.



I'm also having my second thoughts about the value of the lower two in phase alone - and the lower one alone.  They seem to overlap in pattern a lot with the other two patterns. (Four patterns total)  It seems all in phase   or the top one 180 out makes the best and simplest pair of patterns.... 13 degrees and 30 degrees.  But the 180 out as described above has potential matching problems.  The stack works so well as-is all in phase, I'm tempted to leave it alone and let the low angles do the work most of the time.  It's no small job to build up the switching relays and phasing lines and climb up there to install and test.  Just like combing a $2,000 hairpiece.

Any ideas?

T

Looks like you'll be making some L-networks.

Might be easier to build a high angle antenna for NE. You don't want a bunch of switching up on the tower. I would bring all the switching to to the ground if you want to play science project.
I'd tend to leave it as is. Since it works so well.

Frank,
Yep, I modeled a high angle system and it looked FB for a long boomed Yagi or collinear elements at 65'..   Though it adds more interaction to the antenna field.  I'll bet in the end, the stack is still the best performer, even at higher angles like 20-25 degrees. Above that, then the ionosphere is disturbed.


Steve,

I can just imagine switching in and out additional L networks. I'll be up to 12 relays in no time...

Even though I bought the relays and cut the phasing lines already, maybe I'll try modeling an ass kicking NE wire array at 65' to fill things in.  How about 2-half waves in phase with end-to-end reflectors and a bunch of directors?  Or a 7 el delta loop?  Problem is, the only open area is to the side of the stack and modeling shows the stack interacts poorly with stuff to the sides.

When you three guys come over for HossTraders, maybe I'll put the Huzman Delta Loop Company to work... ;D

T

Why not just run the bottom or center beam alone for high angle and screw all the phasing stuff. Then you don't have to add any more antennas. You didn't get into trouble until you messed with phasing. How about duplicating the first configuration that was high angle and matched. I think you are trying to get too fancy making life complicated.  I still think your best bet it to bring the feed lines to the ground and play there.

LOL

Heard on 40 just now from a 4X4 - "What are you doing there, is it MAGIC?"

Yea, that was funny. 4X4BL was incredulous. He couldn't believe Tom's signal.

So you were listening in from Greece, Johnny?  Does it feel like you could make the TX path back based on some of the stations we worked - using your short wire?

Yes, last night was the BEST low angle night on 40M to date. I had one middle east station see about 30db between the reference dipole at 45' and the stack later on. I was on until about 1:30AM... four hours last night.  It appears that the 13 degree take off angle is gonna be perfect for all around use. I was really worried that it wud be too low for Western Europe, but with the performance for long haul, it's a good compromise.


I was amazed last night with Huz's hearing ability. He added a second beverage the other day (two phased) and could hear about anything thrown at him.  I just KNOW there had to be people scratching their heads down in 4-land about what he had running there... ;D

That was a great time last night with lots of laughs.  Hope you join us, Frank, after raising that new boom today and getting your new array fired up.

Frank,

Unless I run ALL three Yagis in SOME kind of high angle config, the reduced gain results in a lobe that is not much different than the all-in-phase config. ie, At 25 degrees, the lower Yagi is about 11dbi. The in-phase stack is also about 11dbi at 25 degrees. (Down from 15dbi at 13 degrees)

So the only config that makes sense is the 180 degrees out, using all three Yagis for a single lobe at 30 degrees.  But there are matching and phase issues.

To bring the feedlines down to the ground would add additional losses and expense for more feedline. If it doesn't work out I'm stuck. So I may just leave it all alone and have a more reliable system with no switching at all - all hardwired using no connectors - bulletproof.  The low angle in-phase config seems to work well 95% of the time - and may turn out to be best 100% of the time if the experiment fails...  Maybe next year I'll get antsy.

The bottom line is I never expected the optimum angles to be so low into mid-Europe and Russia/ Middle east, but they appear to be so at this time.

T

 I have come to the conclusion following all of this for weeks that HUZ and JJ are having too much fun.  :P

I am attempting to get my antenna back up in the air. if I can stumble around a bit more today without crapping out.

The band went really long. I couldn't hear you after a while. There were some Russian stations calling but I don't think you heard them since they just kept calling.

I moved up to 80 meters for a while. The place was hopping. Lots of nice signals from EU-land. I bagged it at around 2:30 AM. EU stuff was still coming through even though they were in daylight.

Yep, I was listening.  I trimmed the wire a bit so now I get +/- full power out of the TS-50.  I'll listen and give you a call when I hear ya again.

I'm in pretty tough shape here.  All I have for radio stuff is the TS-50, the power supply, a 10' length of RG-59 scarfed outta the trash at work, some wire, and a few clipleads.  My sea freight's on a truck somewhere between here and Holland, which should have an ample supply of radio goodeez, including the FT-1000, a 1KW solid state leenyar, a Junkston 1KW flashbox, the Agilent service monitor, a network analyzer, parts, pieces, etc . 

My little Caddy is sitting in a container in Pireaus, awaiting customs clearance.  Taking the frigging bus is getting REALLY old, 'specially going food shopping.  'Sides, first on the agenda is take a pic of me in front of the Cadillac wearing my bigassed furry Uncle Sam hat that HUZ so generously gave me as a going away present  ;D

You were hearing exceptionally well on 40M last night.

Last night those mid-European stations kept calling us and many times covered up the Russians for me - even when we repeat over and over "Russians and mideast only." I don't know if they just don't understand or they want to slip through the net... ;D    I don't have the heart to tell them to shut up while we work the weak ones, but maybe next time.  They seem to eventually catch on when they get no response.  Heck, western Europe can work us any time, but when the band is long, it's a rare opportunity for the weak ones to get through.

Yeah, after I left 40M I listened to 75 and heard some UK stations holding court. I think I'll try 75M tonight. Haven't even tested out the new 75M delta loops yet, so might as well.  We'll let Frank have 40M all to himself.  If 75M is dead, we'll try 40M again for some action.


Johnny,  yes give a a call. We'll make a special effort to pause for you at times, in your caddy and fat cat US hat.

T

It got so bad an HB9 station used a fake RU3 call just so you would come back to him! Everyone wanted to work Tom Vu! It must be magic.
 

Looks like the 75 meter array is working FB too.  :o

M1WDK           3793.0 K1JJ         5.9 plus 50 db tom cq cq EU        0129 20 Sep

Boom is built ropes are strung. Hopefully Sunday I'll suck in the gut, strap on the belt and haul it up. Got stuck in a parade during 1 trip to the hardware store. Then I run into a high school pal I have not seen in 15 years. Just got home from football. My turn to help load stuff and put it away. I had to be very careful not to stress the back.

I agree Tom, don't mess with success. You can fill in western EU with mr ugly.

The delta loops are working FB, Tom.  It's almost 8AM here in SV and yer still S-9.  Before sunrise you were stronger than the Italians - and that's quite a message!  Now I can't hear most of the EURs at all.

Tom ran everyone off the band. Even his old DX homies couldn't keep up with him and gave up. WHIRL WIDE!

Hey, that's cool, Johnny!  Not bad for you to hear that well on 75M with the short wire. Yep, figured we'd give 75M a try for the first time in many months. That was the first trial of the new pair of delta loops at 190'.  It has switching NE or SW and the front to back reports came in at 20-30db. So I'm happy.

I thought maybe 75M was dying out cuz of 40M activity, but later in the night (11:30 PM local)  the Euro pileup grew so thick and deep I had trouble pulling out a letter sometimes. I'm still recovering after holding court continuosly for about 4 hours last night. Gawd, it was fun! There was latent demand built up like a sewer pipe I guess. I took out my screwdriver and unplugged that little hole in the bowl and all hell broke loose... ;D

I'm still amazed at the HUZman's hearing ability - this time on 75M.  He was hearing better than two big guns up here in the Northeast. They took off after passing on a few stations, while the Huzman hung in there and continued to give out reports. I'm cornvinced it's his FB VA location with the lake and swamp to the northeast  towards Europe. His bevs help and he expects to get up a phased array on 75M of some kind. The locals are gonna be in for trouble up here... :o

I took a look at my Beverages today as I was making some final connections and sealing up the coax fittings. One of the bevs was unterminated! It wasn't the other day when I checked. I probably could have heard much better. I was wondering why there wasn't much difference between the dipole and the bevs last night.  :(

Here's Tom strapping in Saudi Arabia on 40 meters.

http://www.amwindow.org/misc/av/K1JJ-Saudia%20Arabia%202009-09-20%20031355.mp3

Heheh... thanks for uploading it, Steve.

Yep, Abdul/7Z1CQ  sent that along last night. It's interesting to hear what it sounded like in Saudi Arabia.  Abdul appears to have a good recording system.  I notice the signal to noise was MUCH better on this recording than the other two videos from Turkey.  There's virtually no static in the background. Yesterday, when this recording was made on 40M, it was a very low angle night - and it shows in s/n.


T

Here's some pics of Frank / WA1GFZ's new boom for his 40M wire array.  Notice the nice job he did on overhead trussing, pulleys and the boom to tower brackets.

This will keep a pair of inverted vee dipoles or delta loops high in the air, off the ends of the boom. This is a clean way to get a strong support for all kinds of experiments. Notice he can raise and lower the elements from the ground, once installed.

This is today's work, so we expect some antennas up next week.

T

I'll be back on 40 in a couple days after I retune the feeder system. The bees got very unhappy with me at 55 feet and started landing on me so I bolted the boom at 55 feet. It isn't 3 duces but will get me on. New configuration let me remove 80 feet of coax from 1 run so everything needs to be adjusted. Also carefully measured the feed line lengths so I don't have to guess. I didn't put baluns on the feed lines yet. All my rigging stuff is at GFZ south so had to carry the boom up the tower what a work out.
Huz how far apart are your  RX antennas

Notice my size 12 sh1t kickers wedged into the tower around the Log drive shaft.
Rohn 25 is the biggest tower mistake I made 30 years ago to save  about $200

More WA1GFZ Boom Pics:

Notice the competition is getting nervous....

They are spaced 20 feet and staggered 25 feet.

Wow 20 feet is close. I wonder what happens at even closer spacing?
Thinking parallel plate type antenna.

Not for beverages. No coupling at all. They are lossy and non-resonant. Some people space them only 10 feet.

Do you use 1 feed line and a load at each far end?

Frank,

Nice boom installation on the tower!  I need to do something similar to support two diamond shaped full wave loops, but wanted to hoist the whole thing up the tower with a pulley and rope.  My initial attempt to use a lighter structure using PVC pipe was just too flimsy (even with support ropes).  Guess I will use some 3" aluminum tube and try to get some help to get it up on the tower at the 72' level.  I just don't like to climb much any more.  My tower is 38" across the face and I climb up the inside of it, so at least that helps.  Even my single loop works great on 40, so two should work really well.  I plan to try some different feed arrangements and see which works best.

73,  Jack, W9GT

Jack 2 inch 1/8 wall will be fine if you use the guy cable truss. I'm glad Tom talked me into it. I used 1/4 inch guy wire. I was surprised how easily I could bend the tubing once it was bolted to the tower. I think you could stand on it now. I would have pulled it up with a rope and pulley if rigging wasn't 60 miles away and I just belw my wad on SS hardware. I sure got a work out lugging it one step at a time.
I double nutted everything and the clamps are not cheap. Also used lock nuts as the second nut at the boom ends. 38 inches on a side, I don't feel sorry for you unless you wear bozo the clown shoes.  I have a number of different configurations to simulate but will start with dipoles. I saw some nice FB with it hanging from ropes.

The back beverage is fed through a 180 degree phasing transformer and a 34 degree phasing line. This connects to a combiner with forward beverage. From the combiner, there is one coax back to the shack. The cool thing is that the phasing tracks over multiple bands.

This phasing arrangement is an old technique, although newly discovered in the amateur radio ranks. I used directive arrays by a commercial manufacturer back in the 1980s using this phasing arrangement. They were based on a patent from the 1960s. I built a system using this arrangement using short dipoles in the early 90's.

Very nice job, OM. Yep, you could probably walk out on that boom now.  A great breadboard for experiments now.

I use overhead trussing on EVERY boom that will bear weight... especially for those surprise ice storms that happen overnight.  The only thing to worry about now is the 45 degree side bend under ice load, but the dipoles will help guy the booms sideways. Though, a big ice load will still pull the boom sideways to down.

Here's a picture of my own boom installation. It's new, just put up two months ago. It uses a 3.5" diameter center with 3" extensions to 2.5" ends, 1/8" wall. It's 40' long and sits at about 188' using 1/4" cable overhead trussing. It uses TWO overhead trusses - one out 7' and the other out 19' from center. The shot is a little fuzzy cuz of the telephoto shot needed. (no tripod)  I tried to squeeze as much height as I could outa it....  Pulled it up using the car and a group of well placed pulleys /ropes.

Notice the sidearm and the safety rope. The boom hangs on a steel "swivel" and puts no twisting torque on the tower. It is guyed by the delta loops. In the wind there is a slight back and forth swing to it. Torque can take down a tower so I go to great pains to minimize it when I can.

The delta loops for 75M are switchable NE/SW using the HUZman's coax stub technique.  On the tower at the end of the coax stubs I add a coil to make the loop a reflector and drive the second loop directly with a balun. Switching directions simply switches the connections to each loop coax - with the relay.  20-30db front to back reports are common using this system.

T

Steve cool on the phasing like a delay between two directional couplers speed of light related not frequency. I wonder if I could use your reverse pattern switching at the end of a long coax by switching an open or shorted stub. My feed lines are 100 feet long and would like to switching in the house.

Nice looking setup, Frank. Looks a lot better in the daylight. It'll be great having you on 40 as a regular soon.

After calling CQ on AM with no replies over the weekend, I decided to haul the KWM-380 you fixed for me up off the floor for some DX work. Managed to snag Belgium, Ireland, Germany, and Romania with a pissweak 100 watts into a paltry half wave dipole up about 15'. Heard a 9K2 in there really light copy, Johnny sez it was Kuwait(!). Fun stuff, takes me back to my DX days of the mid-80s.

Heard the HUZman holding court down around 7133 talking with Ian GI3DZE and a few others, tag-teaming with a K2 station. Those phased loops really do the trick for the DX Cannon.  ;D

That was Steve, K2 Fuzzy Wuzzy. You'll find him running AM on 75 meters on weekend mornings. He has a nice 2-el Yagi at 90 feet on 40 meters.

We we get your antenners up proper, you'll be WHIRL WIDE.

BTW, I heard some moron slopbucket on 3740 kHz the other day bragging about his 20 meter beam and how he worked Spain. BFD, you just did better that on 40 meters. Working DX on 20 is like shooting fish in a barrel.

Well just got off 40 and worked an IK.. VSWR sucked and FB only 2 S Units so kept it at 50 watts. Then did a sweep. resonates nicely at 7.4 MHz. I should have not chopped the ends last week when it was closer to the ground. 

Keep playing wid the configs until you zero in on big results. I wud stick up a ref dipole, even if it is low and at right angles... just to have a baseline.  There IS a perfect situation for you QTH - you just have to find it. It took me years to finally figure it out here.

My own breakthrough was discovering phased beverages, stacking for low angles, canceling high angle lobes, fine tuning for maximum f-b and dual diversity receiving.   Receiving is what matters. Transmitting takes care of itself.

T

If you are going the phasing route, make the two dipoles the same. Then determine the feedpoint impedance and cut your phasing lines appropriately.

If you go the parasitic route, cut each dipole to the desired freq independently (you don't want any interaction). I would cut them high in frequency since it's likely once you add the second element the resonant frequency will drop. Then connect your stubs and check the freq. Trim the length of both dipoles as needed to get the resonant freq where you want it.

the VSWR is flat at 7.4 MHz. so it should work fine once I reinstall the wire I lopped off. My simulation says force fed better FB and loops even better.
I let the program loose on top fed loops and it configured it self as folded dipoles with the bottom a foot below the feed point. I need to play with that one since it gives loop FB performance with higher average height. VSWR wasn't great though

Regardless of what the computer and swr says, in the end, expect to spend time up on the tower tuning for best front to back. Put a beacon out in the woods a few wavelengths away or use a receiver tuned into some W4's to null it out. Pull that sweet spot f-b into the 7150 area.

I used my cell phone up on the tower to tune the 75M delta loops. I listened to my inside house telephone that sat by the receiver speaker tuned to a beacon I placed out in the woods 1/4 mile away to the SW.  My stubs were off and I quickly pruned them to get the beacon into the noise. Since the beacon is at  zero degrees on the horizon, (actually negative elevation)  it wasn't a perfect representation of the real whirl at 10-30 degrees on the air. But still, my actual f-b reports came in at 20-30db and I could tell by tuning the receiver around and switching on the W4's where the sweet spot was.   Fine tuning needs to be done for max performance unless the system is very broadbanded.  Parasitic elements are usually tuned sharply for a narrow range and need this extra effort.  Mud ducks need not apply... ;D

T

Don't get too wound up about F/B numbers at any one elevation angle. You can play with things to make a big null at one angle and have crap elsewhere. Look at the entire back side of the pattern "optimize" it. Also look at the high angle respone on both the front side and the back side of the pattern. Minimizing the response in these areas will pay far more dividends in receive improvement than a big null at some single lower elevation angle. In other words, unless you have a lot of local noise, trade off lower angle F/B for better higher angle F/B.

F/B at a zero elevation angle is worthless, unless you are trying to remove local groundwave propagated noise or doing BC band DXing. Select an angle like 30 degree to work with. You can still do this on the ground. Just set your signal source 30 degrees off the back of the array (e.g instead at 180 degrees, put the source at 210 or 150 degrees azimuth). Tuning for a null this way will also give you a null at 30 degrees elevation.


I think you may have a modeling problem there. Folded dipoles will act no differently than a single wire dipole in an array when considering F/B or gain (other than maybe some loss reduction in a low-Z situation). Real loops will have greater coupling than dipoles, thus the currents are more nearly equal. This is what yields the higher F/B.

The beacon in the woods antenna is limited to about 50' high in the trees. So, it will always be at zero degrees or less cuz the main antenna is much higher on the tower.  I COULD float a balloon up to 1000' to simulate a higher incoming angle... ;)

I've found tuning the reflector at zero degrees elv to be a FAIRLY good representation of the real whirl angles at 30 degrees elv, etc.  I use zero degrees elv beacon for getting in the ballpark cuz a long, stable tone is needed without fading - to fiddle around. The fine tuning is listening to the W4's off the back on the receiver  as the array is switched.


BTW, I don't follow how when a source (beacon)  is at zero degrees elevation, how moving it to one side or the other will represent a higher elevation angle to the antenna.  A source at zero degrees is still a source at zero degrees elevation, just off to the side, right?  Please explain the geometry, OM... ;D

T

I won't go into all the trig here but the short answer is that with most simple arrays, if there is a null at a particular elevation angle, there is a corresponding one at zero degrees elevation and azimuthally (is that a word) at 180 degrees + the null elevation angle. Don't believe me?

Fire up your modeling program. Take a look at a two-element array. Play with the phasing. You'll see the elevation null angle change. You'll also see two nulls move around on the azimith pattern when looking at zero degrees elevation.

Interesting.  I've seen the nulls move around, but didn't realize there's a direct numerical correlation between  az and alt that would be useful for beacon tuning.

Thanks for the hot tip, OM!

T

I was out hiking today with Yaz and spotted the 190' towers from one mile away. This is a telephoto shot. (2nd picture)  Look closely to the right side and you will actually see the 40M Yagi elements.  The bottom Yagi at 62' is below the treeline - the other two are clearly above. We are standing Northeast of the towers - the Yagis are beaming towards us, towards Europe.    Also, to the left, see the boom of the 75M delta loops.

The first picture is from the top of the same 40M Yagi tower looking towards Europe from 190'. Today's picture was taken somewhere in the middle of the 1st picture frame in the woods at 500' elevation. The tower bases sit at 805' elv on top of a hilltop. The ground stays flat for about 600' then rolls off into the valley in our direction - clear shot towards Europe.  There's an airplane in the first picture... ;D

Expand the 2nd pic for a better view, if your software allows it. You will see the two elements on both Yagis.

T

   That's an airplane?  What's that to the left of it, a fly spec on my screen?

Yeah, I see the spec too - there's actually FOUR of them buzzing the airplane. After the picture, the airplane disappeared into thin air. This is solid scientific proof that UFOs exist and we have been harrassed by ET's for thousands of years.

(There's also one hovering above the right tower... taking an RF batt charge, I  assume.)

T

Great shots OM. Gives a good perspective on why you strap into EU.

They say a pix is worth a thousand word, so I made some pix.

As discussed earlier, when adjusting your array for best F/B, you have to pick an elevation angle for that best F/B. Then you measure the F/B not off the geometrical back of the array (180 degrees), but offset in degrees equal to the desired optimum F/B elevation angle.

Take a look at the two plots below. These are of two 40 meter dipoles at 60 feet about average ground, spaced one-quarter wavelength and fed 125 degrees out of phase. As you can see in the elevation plot, there is a null at 55 degrees elevation on the back side of the pattern. Now look at the azimuth pattern taken at 1 degree elevation (essentially ground level). Notice the two nulls in the pattern at 55 degrees either side of 180 (125 and 235 degrees). This is where you would want to measure if you were optimizing the phasing to have the best F/B at an elevation angle of 55 degrees. Also notice how poor the F/B is at 180 degrees or directly off the back of the array - only 10 dB. What would happen if you took a measurement there and "optimized" the F/B? See the next post of the answer......

If we optimized the F/B directly off the back of the array, we would get an awesome F/B, more the 30 dB. (Look at the first plot). But take a look at the elevation pattern! (Second plot). It's kinda lazy looking and lots of high angle response on the back side. These patterns happen to coincide with 90 degree phasing.

If we change the phasing just a little bit, to 110 degrees, look how much better the pattern looks on the back side. (Look at the third plot. Here I compared the 90 degree phased system - dashed line - to the 110 degree phased system - solid red line).

The worst case lobe still produces a F/B of 20 dB, and you have a nice null at about 30 degrees elevation. And notice that the response at the higher angles on the back side is also down. Finally, there's a bit more gain.

There you go. This is why you usually don't want to measure your F/B directly off the back of your array.

Vely vely good info, OM!  You get AMfone 2009 Nobel Prize for Antennas.


I assume these phase changes on a driven array are the equivalent to changing the lengths of the reflector and/or director on a [parasitic] Yagi?


A real-whirl way to simulate this excercise would be to tune in some W4's and null them out on the fly.  It wud require climbing the tower to be up where the stubs or adjustments were.

There was a time when I brought the openwire stubs for a 3el 75M wire Yagi into the shack for remote tuning. About 250' of openwire for each element. I had roller inductors across both the dir and ref. I could null out stations off the back like you wudn't believe. With a set of switches I wud null a station,  then null the other direction - and the array was all set for that freq. 

BUT, even though I used #5 copper wire for the openwire stubs into the shack, I was always down about 5db compared to a conventional wire Yagi with fixed wires.   I later removed them.  I figgered there was loss from using 30 ohm dipole els into 800 ohm openwire... more than you wud normally expect. I couldn't think of any other reason since the gain came back when I eliminated the stubs.  I was using Chuck's 3el rotary Yagi as a baseline into Eu.  It was quite clear.

T

It all a matter of current distribution between the two elements, both ampluitude and phase. You can move the lobes and nulls around by tuning the reflector/director. The tuning can be actual length changes or by changing the amount of inductive or capacitive reactance at the center of the element.

I'm seeing the same type responses in a force fed system when you play with feed line lengths.

That's what I modeled below - a phased system. Of course I modeled it with perfect phasing and zero loss feedlines. The pattern won't be quite as pretty in the real world.

I did a pair of top fed loops and let the program go with bottom height and end lengths as variables. It ended with the bottom of the loops a foot below the feed point. HMMM folded dipoles at 135 degrees.
Reading further landed the real name of that antenna "ZL special"

Or HB9CV, depending on the variation.

Well just finished some testing in RX. FB is really good tonight around 20 db on the stingy TR7A. Checked in the West direction and it is also good. Then did a sweep and have good VSWR 7.250 to over 7.450. I think I'm pretty close just have to add wire back on the elements I lopped off last week when it was closer to the ground.
Maybe the simulation looked better with a flat  loop only a foot tall because the average height was 20 feet higher?? FB was 30.

20db is vely acceptable. Hopefully you will see 25-30db f-b on certain nights on certain stations.

Just to axe the obvious: Where are you measuring the swr on the line?  You're using a 1/2 wavelength coax multiple, right?   Otherwise, as you know, the readings will be something different than what is really at the feedpoints.

T

I'm only looking at the SWR at the rig. I'm sure it is different at different places along the feed line. Feed line lengths not balanced. actually 135 degrees off to favor west. I just series a bunch of coax jumpers to get the right delay to flip it East. No football Thursday so I will work on it some more. More luck than science at this point.

Just to be sure...

Your swr may NOT be good from 7.250 - 7.450 at the dipole feedpoint, where it matters.

Add whatever jumpers are needed to give you a multiple of 1/2 wavelength to get an accurate swr reading of the dipole feedpoint. (with velocity factor)  THEN adjust your dipole lengths.  Otherwise, if you really have an swr problem with either or both dipoles (and don't know it) your 135 degree phasing line may be something far removed from 135 degrees due to the swr.   IE, your total coax length should be 45.4'  or 90.8', etc to see a real feedpoint reading for each dipole. Once they are tuned independently and the swr is really 1:1, then play with phasing lengths.

I usually tune my delta loops up on the tower with the feedpoint temporarily pulled to the tower.

[Maybe I'm preaching to the choir, if so, then maybe this will help some others...]

T

The SWR is never going to be good at the feedpoints with a phased array. And the feedpoint impedances will be quite different with the 135 degree phase feed. You can only be concerned with matching/proper SWR AFTER the two feedlines have been joined.

Yep, understood.  I'm talking about getting the dipoles set up equally before playing with the phasing lines - and to get the two dipoles resonant on 7150 to begin with. What if one is way off due to an error in cutting?  I'm not sure if Frank did that using 1/2 wavelength feedlines first. This error would show up when switching directions.  But they're probably close enuff, knowing Frank's attention to detail.

I can understand the 135 degree phasing creating a reactive condition at the feedpoints.    Though not all phased "arrays" have swr problems at the feedpoints. For instance, my 40M stack has a theoretical 50 ohms  J0 at each feedpoint (when joined into three components) and measure out pretty close in practice. (They are all fed in phase, however, not 135 degrees out - and are complete units, not individual elements within an antenna requiring specific phase treatments)

As discussed in the past, I've never liked the complexity and potential matching problems of driven arrays vs: the simplicity of parasitc arrays. They both can be gotten to work, however, and a driven array is even a better choice for a low antenna below 3/8 wave above ground.

T

Tom,
The VSWR measured at the TX reflects the fact that I lopped off a foot of wire at each insulator when I was closer to the ground. I'll dial the rest of the system in when the coax lengths when I get the antenna right. I agree with HUZ the antennas will not be perfect 50 ohms in a force fed system. Read the article i sent you. fc

What do you figure the swr (input impedance) will be for each dipole feedpoint and what is the expected total length of RG-213 coax for each dipole?

Remember that even 1/2 db of additional loss due to swr = ~12% of your forward gain.  In contrast, the  parasitic array competition has none of this additonal loss... ;)

T

Good point 10 MHz. RG213 loss is .66 dB/100 feet plus VSWR loss. I guess this is the price I pay for force feed with the option to flip the pattern.
I wonder what loss you would see in a Stub switching system like Steve has? I wonder what loss you see in a 1/12 wave transition or a wilkensen.
A single antenna in a single direction is best for sure.

Tom the article I sent you said the two dipoles look like 122 -J41 and 34 J39.
I dumped the values into the transmission line calculator to see what 100 feet of RG213 did with the load. Matches loss at 7.15 MHz .53 dB. Total loss of each is .76 dB and .74 dB. So we are talking less than 1/2 dB  additional loss for both lines.
I wonder how that compares to restive loss of two feedlines at QRO.   

There was a thread back a few months ago where I axed W2DU what the return loss was on a 1/12 wave balun.  I believe the db loss was down around 1/10th db, but I'd have to check.  Though, my stub switched delta loops don't use a 1/12 balun.

The loop's input impedance is something like 100 ohms, depending on how tighly tuned it is with the other element.  So using 75 ohms coax = about 1.3:1 swr on the stubs?

What does your model say for the two dipole input impedances when 135 degrees out and working well?

T

That's a moderate swr, but the resultant losses don't sound too bad.

But it sure hurts to give up 18% of our forward gain in coax losses though... :o  Heck, I have 420' of underground hardline going to the stack from the shack... plus the phasing harnesses -  don't feel bad, OM.

T

I bet a PL259 loss is interesting. They are around 35 ohm Z and that is if you solder them correctly.
Tom, you could always move the shack out to the field if it ever gets to you.

I calculated the stub loss at a few tenths of a dB. They are quite short and the SWR is low, well less than 2:1.

PL-259's?

I've had poor luck with them out in the field. They eventually go intermittent on me from moisture, even though they are well sealed to the WX elements.

All of my antenna phasing lines are hardwired together. I do my best to simulate a 50 ohm situation by keeping the inner conductor covered to the last 1/2".  I mean, after all, how much of an impedance bump is an open frame relay out there compared to a hardwired coax connection?  

When measuring I rarely see 1.1:1 difference using hardwired connections.  I do it all the way to 50 mhz. That old 16 bay 6M stack used the technique and the swr was FB.

Darn, my Milwakee drill just crapped out. I'm dead in the water and need to hit Home Depot.   Gotta have a drill.

T

Tom it might just need brushes...Check Sears they might be cheaper for the same item.

So sounds like Huz configuration and mine are a wash for loss.

I've been a type N guy forever. I like the tall connectors with the bug rubber gasket. Then cover them with a good layer of tape. HN even nicer. They go well with Bird switches

I modeled two dipoles spaced at 20 feet, phased at 135 degrees and at a height of 55 feet above average ground on 7.160 MHz. I first set the length of each dipole by itself to be exactly resonant at 7.160 MHz.

The feedpoint impedances turn out to be as follows.

Leading element (zero phase dipole): 18.2 - j35.6
Lagging element (135 phase dipole):  48.0 + j61.9

To get the proper phasing with RG-213 cable, the leading (zero phase dipole) will be fed with 16.333 feet of cable. This will result in a loss of 0.32 dB. The lagging element (the -135 degree phased dipole) will be fed with 72.85 feet of cable. This will result in a loss of 0.6 dB.

The impedance at the point where the two cables above are joined will be 14.57 + j0.86. That makes for an SWR of 3.44 and loss of 0.97 dB in 100 feet of cable back the shack. All told, there is about 1.5 dB total loss. Placing a matching network where the two phasing cables join and the loss is reduced by about 1 dB (minus whatever loss the matching network may have).

Wow. That's quite a message!

Looks like Frank should make up a transformation out on the tower.   14 ohms is VERY low at the junction.

I have the same problem here.  When I join my three 50 ohm 40M Yagis, I'm down to 16.6 ohms. I use a 1/12 wave balun to bring it back up to 50 ohms for the hardline fed at 125' high on the tower. Works great. Maybe Frank already plans on some kind of coaxial transformation there - or is he running both dipole coaxes into the shack? - dunno.

T

What if you cut the dipoles a little short?

I modeled two dipoles spaced at 20 feet, phased at 135 degrees and at a height of 55 feet above average ground on 7.160 MHz. I first set the length of each dipole by itself to be exactly resonant at 7.260 MHz.

The feedpoint impedances (at 7.16 MHz) turn out to be as follows.

Leading element (zero phase dipole): 17.235 - j56.138
Lagging element (135 phase dipole):  46.478 + j37.478

To get the proper phasing with RG-213 cable, the leading (zero phase dipole) will be fed with 18.998 feet of cable. This will result in a loss of 0.54 dB. The lagging element (the -135 degree phased dipole) will be fed with 74.858 feet of cable. This will result in a loss of 0.6 dB.

The impedance at the point where the two cables above are joined will be 15.15 + j7.43. That makes for an SWR of 3.4 and loss of 0.94 dB in 100 feet of cable back the shack. Looks like the loss is a little worse here.

Steve,
I simulate 41.6 -j3.4  and 16 -J93  the the feed point so we are pretty close. My feed lines are 65 and 100 feet to get into the shack. I just added 15 feet to the 100 footer and 50 to the 65 footer. Just to make them even  Signals to the west great FB but not great to the east. I used this ULA 400 cable for the 50 footer that turns out to be foam dielectric with a VF of .85. I guess it is a version of LMR400.  So East cable somewhat longer (electric length) than I thought.  I'll swap it out with something that matches. Also tonight I added the foot of wire on each 4 wires back on. I really need to invest in an antenna analyzer. I was thinking of hooking up a Z bridge. I have a couple kicking around. I could js an analyzer to find a Z null at 50 ohms but wanted to fix the FB problem. I was seeing a solid 20 dB on the HPSDR to the west. Back to the pit

Well I need to look at that and what happens with an odd quarter wave length of coax which should raise it up. I'm looking at around 5 quarter wavelengths for feed line. I could get by with 3 if I did switching at the base of the tower.

This is an off-the-wall solution, but what if you made a compact variable (un to bal) L/C matching network for each dipole that hung out on the end of each boom mast at each feedpoint?  Using a 1/2 wave multiple feedline you could zero in on the proper match from the ground. Knowing the approx modeled impedance you could pre-set the network in the shack and be close.   This way you could run the coaxes to the shack with no matching and a good swr...   ;D

There was a time when I did that with remote controlled tuning on a rotary 75M Yagi. Worked FB.

But all in all, the parasitic stub technique wud be far simpler.

T

What if you cut the dipoles a little long?

I modeled two dipoles spaced at 20 feet, phased at 135 degrees and at a height of 55 feet above average ground on 7.160 MHz. I first set the length of each dipole by itself to be exactly resonant at 7.060 MHz.

The feedpoint impedances (at 7.160 MHz) turn out to be as follows.

Leading element (zero phase dipole): 19.147 - j15.496
Lagging element (-135 phase dipole):  49.805 + j86.012

To get the proper phasing with RG-213 cable, the leading (zero phase dipole) will be fed with 12.644 feet of cable. This will result in a loss of 0.18 dB. The lagging element (the -135 degree phased dipole) will be fed with 71.356 feet of cable. This will result in a loss of 0.79 dB.

The impedance at the point where the two cables above are joined will be 12.63 - j4.09. That makes for an SWR of 3.97 and loss of 1.09 dB in 100 feet of cable back the shack.

Steve PM me your email address and I'll send you an article a found in the morning.
The guy who wrote it also set the Resonant length off frequency. I'm at 34 feet 5 inches each half right now which is about 7.15
I don't have it here at home but interesting reading. I need to run about 100 feet or so of feed line to get inside or do 3 quarter waves to the ground. I was just loooking at the transmission line calculator and the low z is pretty lossy getting it to the ground.  So it boilds down to 3 quarter waves, 4 quarter waves or 5 quarter wavelengths of coax.
Tom the problem with lumped values is the Z changes a lot when you swap the pattern

Plus the phase changes when the L/C is used, so it becomes even more complex to tune. 

Yes, the two feedlines are different lengths when swapped... I see the problem there.

O'well, bag that idea...

T

Using your Z numbers you have two phasing cable options. The first would be to feed the leading element with a 9.592 foot long cable. This will give you 0.37 dB loss in this cable. The lagging element would be fed with a 40.059 foot cable and you would get 0.21 dB loss.

The impedance at the point where the two cables above are joined will be 9.54 - j15.25. That makes for an SWR of 5.66 and loss of 1.47 dB in 100 feet of cable back the shack.

The other option would be to feed the leading element with a 22.182 foot long cable. This will give you 1.12 dB loss in this cable. The lagging element would be fed with a 80.076 foot cable and you would get 0.43 dB loss.

The impedance at the point where the two cables above are joined will be 12.94 - j18.05. That makes for an SWR of 4.34 and loss of 1.19 dB in 100 feet of cable back the shack.

Lumped values where? And why would anything change when switching the pattern if everything is symmetrical?

Frank's referring to an earlier post where I suggested the possibility of using L/C matching at each dipole feedpoint.

Another thing to consider - we're swinging around big swr mismatches here.  When running QRO, this is a consideration for cable damage, caw mawn.


BTW, Frank - I'm drilling and tapping the second 600w SS FET module.  Remember the trouble I had breaking taps?  Someone suggested to use larger than recommended drills.  They recommend #43 for 4-40 screw. I tried a #41 drill today and the taps goes thru much easier - and the screw is still tight.  Shuda thought of this long ago instead of struggling with those tight holes... :o

T

OK. Got it.

BTW, the loss in the stubs on my loops is about 0.14 dB. The entire system, including the cable back to the shack has less than 0.5 dB loss at the lowest SWR frequency and never gets worse than about 0.61 across the entire span of 7.1 to 7.3. These are modeled numbers, so I'm sure it's not quite that good in reality but if you start out low, you are more likely to end up low. Tight? That's another story.

Well, Just swapped out the foam coax and had a 50 foot hunk of RG 8 then I found a couple short jumpers to extend the delay line out past 90 degrees. SWR looks real good at 7.09. Conditions look crappy tonight so figured I'll quit here.
Well Steve maybe it is worth looking at setting the elements inductive but sure looks like you have a better configuration. I suppose I could hang a box off the center pulley for switching so I could lower if if it needs repair in the middle of the winter.
Maybe I'll simulate all the losses in the article and see if it makes sense. Since you have done this about a million times by now what do you think I will need to do to duplicate your feed method using dipoles as elements with the ends at about 45 feet?
I also want to give folded dipoles another look since they have a higher z or look at a 1:2 transformer up in the air with force fed switching in the air
Tom Cool on the tapping. Whenever I start a new project like that I buy a new name brand tap and sometimes it comes with a drill. I go very slowly and use plenty of oil. I  usually go 1/4 turn in 1/2 turn out and if it feels tight I go back and forth a few times before I go any deeper. Jay found a source of strapping heat sinks if you need any.

Frank said:

"Another option is build a 2 element for North East and hang a second driven element from ropes behind it to do South West sharing the reflector."


But then your f-b is only 12-15db at most with a 2el Yagi. You need more. 

Another idea is to try modeling a parasitic pair of delta loops (apex up)  but with extended bases. (and corresponding shorter sides)  Make the bases much longer than the sides and then avg height goes up.  You can get 20-30db f-b easily and I'll bet the TO angle isn't degraded that much from dipoles.  Plus, use the parasitic stub method and you're back to a clean NE or SW switchable pattern. You can pull the loops out with less space too.

I ran a pair of these "extended base" deltas on 75M for years and they worked out really FB.

Model them and see how far you can push the base length. You will be surprised at the pattern results and f-b of a close spaced parasitic pair.  Even 15' spacing is good. Now, with a 30' boom, you COULD do a back to back common reflector array that kicked ass and NO relays... just two coaxes into the shack. Use a 2:1  1/12 wave balun at each loop feedpoint and you're golden.  Feed them at the top or bottom, whatever is best for you.

T

My simulation shows best performance as a folded dipole with a foot spacing between base and apex. I have not tried to drive it yet. This gets the average height way up

Tommy, for what it's worth, this morning when you switched to Cal you were S3 vs S9 to S9+10.  The F/B is FB.

Hi Johnny!

Was this on 75M?   (Steve and I held court on both 40M and 75 tonight)

If the S-Meter is accurate, that's about 46db f-b...  ;D   That's the 2el delta loops at 190', caw mawn.

Are you ready to try a test? We can possibly try it tmw night local time on 40M.

T

Yeah, 75, 3800 KC.

My laptop running my Skype server has crapped out.  Hopefully I'll fix it today (the boot record got corrupted).  I can still get calls on Skype using this computer but it's not convenient to get to the radio room with the phone til I get the other laptop fixed.  I'll let ya know and PM my phone # (it's a 301 area code).

The guess meter on that TS-50 is *fairly* accurate, as I recall, and integrates the peaks pretty well.

anybody look at loops spaced 5 feet apart. I'm seeing a nice VSWR darn close to 50 ohms with a reflector / driven element. FB not super but ok but gain 10 dB. Thinking of a second driven loop behind the reflector for the other direction....then tune it as a second reflector. The thought is kick out the bottoms of the loops to get more spacing if required

Tom, I saw 20-30 dB F/B last night on the loops. That's quite high considering the distance. The EU's were seeing in the mid-20 to 30 dB on a couple. That muddy water slapper is talking!

Well, dialed in the driven dipoles and nice VSWR but FB not great. Worked a few stations but doesn't look all that great. Maybe it is time to move on to something different. Yes a driven array can demonstrate nice FB but I'm starting to think that is about it

OK Frank,

You will probably end up with the parasitic tuned switchable stub method that both Huz and I use.  Take a look also at the extended base delta loops I posted a few posts back. If ya want big f-b, you either need a 3el Yagi or the 2el delta loops. A 2el Yagi won't make it F-B wise.

 Going sailing wid Yaz today. Last good day of year for getting wet and windy, I think.  Great night on 75M and 40M last night. Worked over 150 stations in pileup on both bands. Lots of Russians and some middle east on 75M too. The angles are very LOW lately on both bands.  Hope  you get something going soon, OM.

T

Tom, I have a nice simulation of a 10 foot tall delta at 10 foot spacing that looks great into 50 ohm coax with a stub on the reflector. Third element is funky. I might just do two element fixed direction. I have not been able to simulate HUZ bandwidth yet, I'm tigher. I have the simulation set up to tune the stub length and it ended up within 6 inches of HUZ loops. The 2 element dipoles give me a bit better perfromance so far. 20 foot spacing short deltas with points up are not as good as dipoles so far. 

You're on the right track now, Frank.

Do whatever it takes to get a f-b of 25db+.  Again, a 2el simple dipole Yagi won't do it.   I think delta loops at the top of your tower (68'?) is the answer.

BTW, paper wasps like to fly around and circle towers for some reason. They do it to my towers all the time. It doens't necessarily mean they have a nest up there, so don't be afraid to climb to the top. If they do, they are usually pretty docile creatures anyway. (not including hornets)


Check out Yaz's excellent adventure here:

http://amfone.net/Amforum/index.php?topic=21375.msg152014;topicseen#msg152014

T

Tom, Best FB on the dipoles was about 16 dB. Right now I have a 3 element delta loop running simulation for the past hour. FB 25 to 30 db with 10 dB of gain. Tuned stubs on the front and back with center driven. All on a 20 foot boom. Waiting for it to stop so I can change to 70 ohm feed line 50 a bit low. Input Z running around 90 ohms. Still searching for the right variables. It is tuning both stubs front and back loops then tuning the center  so plenty of stuff to tune.
If it works I'll be able to swap the pattern by swapping the two stub lengths.

Tom, HUZ, Frank....

Have you guys looked at the "triangle" or pyramid variation of the two full-wave loop antenna?  I have an old Ed Noll antenna book: 73 Vertical, Beam, and Triangle Antennas.  In it are several versions of the loop and multi-element loops and also a triangle or pyramid version.  Basically it is nothing more than two delta loops with the apex of both very close to each other at the top (opposite sides of a tower or mast)....then the bottom legs and base of the loops are pulled out 1/8 wavelength from each other on the bottom.  The effective spacing then varies from a couple of feet or so at the top to 1/8 wave at the bottom.  Seems like this might produce a higher angle of radiation off the front, but it is mechanically much easier to accomplish since the boom would not be required and a common top support could be used.  I wonder if you could model it and see how it looks?

Tom, another interesting thought for an experiment with the 40 M yagis would be to extend a 1/2 wave length of wire from the tip of each element...let it hang down and connect to the tip of the corresponding element of another yagi below it.....resulting in a two element two wavelength around bisquare.  Looking like a really big (double sized) quad.

I thought about doing something like that with 20M yagi elements and making a full-sized 40 M quad.  The advantage of this over the diamond loops would be a higher center line of radiation.

Anyway...lots of fun.  I hope to get the second diamond-shaped loop up here shortly....we'll see how it works.  I now get really great reports from Europe and manage to break thru the east coast curtain fairly well with the single loop.   ;D

73,  Jack, W9GT

Hi Jack,

OK on all the loop info. Interesting ideas.  Yes, the "no boom" deltas oughta work. I have even seen Yagis model out well where the elements are not square. They worked on their average distance to produce the pattern.  Though with Frank already putting up a boom, I doubt he'd bother to try it now.  But others without a boom may. I've also seen a variation- on 160M, a four square that had the wires start at the tower and pulled way out. It modeled out pretty well.

BTW, I heard you on ssb a week ago working a Euro on 40M.  You sounded excellent!  You had punchy, well tailored audio and sounded like a cross between a relaxed contester and sophisticated DXer.  Very nice ssb presence, OM.  Hope you get the second loop working.

After I came back sailing yesterday, it appears the high winds rotated my top 40M Yagi from perfectly horizontal to slightly vertical. I obviously didn't have enuff clamping on the boom to keep it from twisting. I figgered the overhead trussing wud stop any longitudinal rotation, but NG.   Now gotta fabricate up three new brackets to clamp another part of the booms to the tower- on all three Yagis. This will also keep the beam from rotating in the horizontal plane.  It's good it happened now, cuz the winter 50mph+  winds wuda messed things up for sure and I'd be stuck all winter looking at it...  >:(   So gotta get some new SS 3.5" U-bolts and go to work on it. I thought I was done climbing for the season too.

T

Jack,
I ran out of steam last night and didn't get a chance to set the bottom of the outer loops spacing as variables so the program would find the right distance to move them away. When I stopped the the gain was around 10 dBi with over 25 dB of FB. Also the input Z was high enough that a quarter wave of 70 ohm coax or 70 ohm feed would produce a nice match. The bandwidth of the antenna is fairly tight though, unlike the HUZ design. I'm thinking real world coax and stub losses give a wider bandwidth. It looks like adding a third element improves the FB but not by a lot. Bottom down loops do not seem as good as flat side up. Nothing like simulation and a pulley system to make life easier.
Tom Vu needs to build a Joe Hunt magneto clamp so the beam doesn't turn.   

Sounds like a good model, Frank.  2el shud be enuff for a good F-B on the deltas.

Here's a picture of the top Yagi with the spun boom.  I be on the way to vertical polarization like the good buddies.   I found some steel angle and gonna make up the additional side arms with THREE 3.5" u-bolts to grab the boom for each Yagi. That oughta do it.

A good eye will see the top Yagi is off by about 15 degrees or so.  It will probably get worse if I do nothing.

T

Thanks very much for the kind words Tom.  In a former life, I was a very active DXer and, to a lesser degree, an avid contester.  My former call sign: N9GT was fairly well known in those circles, although I never quite reached the honor roll.  After realizing that, for a number of reasons, I could not continue to be as commited or as competitive as I wanted to be, I became much less involved in those endeavors.  I still really enjoy working DX and occasional contests, but my main interest for the past several years has been AM and vintage gear.  I also really enjoy building amplifiers and playing with antennas.  I have certainly enjoyed following your exploits in those areas.

I wish I could physically meet the challenge of running up and down my tower like I used to, but I don't do much climbing anymore.  That is one reason I was searching for a way to easily hoist loops and/or other stuff up and down, without having to climb.  I really enjoy playing with the loop antennas on 40.  It is much easier to be competitive on that band if you can get anything bigger than a plain old dipole working.  Hopefully, will get the second loop working soon.....we will see how much difference it makes.

73,  Jack, W9GT

Tom I wonder if you should put some rubber between the clamps and boom. Say rubber from an inner tube?? Something to add friction???

Hmmm.. I'm not sure if adding a wafer of rubber will make it slip more or hold it. It will at least have some flex to it.

I climbed up there today and took measurements so I can make up the sidearms tonight. As the wind blew the booms around I could see that it definately needed some additional bracing. The horizontal side to side motion was held only by a few inches of the center bracket - no leverage. The overhead trussing did nothing in this plane.  The addditional side arms will make it real solid by adding leverage and ALSO prevent boom twisting from the long elements.   I think the three additional boom u-bolts shud do it.

You shud not have the same problem cuz the loops will guy it for side to side motion - plus you have no element twisting motion to worry about.

BTW, what is the antenna dajour ?   ;D   Have you finalized a model to put up yet?




Jack - FB on the contesting and DXing in your prior lives.  I truly enjoy getting on when there is bad static and nobody on cuz they think cornditions are bad. Then with a few CQ's, Europe comes alive creating a pileup for the next few hours. That is such a thrill to me, especially doing it on 75M! Then the Euros start saying conditions must be great... ;D  Maybe we can work in tandem in the future.

T

Tom,

If you could drill a hole thru the boom without weakening it too much you could effectively pin the support arm to the boom preventing any twisting.  I think the rubber under a clamp might deteriorate, especially with New England wx condx.  Stainless muffler-type clamps are pretty strong and with a pin/bolt thru the boom fastened to a piece of angle material also fastened under the clamp nuts...it would be really strong.  I did something like that on the center support of my big (60' boom) 20/10M yagi.  I used really heavy thick-wall tubing for the center portion of the boom.  It had overhead truss-guys on the boom, but had problems with it twisting...that was my solution.  Worked great until a tornado passed over and wrapped the boom around the tower.

73,  Jack, W9GT

Jack,

Yes, pinning is always a good idea. I've done it to all my elements, including the 40M Yagis.  I didn't do it to the boom cuz I wanted the flexibility for exact adjustments.  What I'll do then is drill the new steel sidearm bracket for a future pin, but not add it unless I have to.  If needed later, then I can simply drill thru the aluminum boom while up on the tower at some future date..  The boom is only 17' long and the center section is 3.5" 1/8" wall, followed by 3"  extensions. Pretty much overkill.

T

Tom,
No Antenna simulation the past two days. Peter broke his arm in 2 places taking a block as he was about to sack the QB. We thought it was just a strain until we saw the Xrays. He will be ok but out for a while. I will be doing something different if the WX isn't too wet this weekend..

Tom,
Are you using good saddles on your U-clamps?  In the past most of my troubles with slipping booms or slipping mast clamps have been attributable to saddles that allow the tubular boom or mast to slip due to lack of 'grip'.  No amount of tightness or number of clamps can make up for bad saddles.
73, Karl

Hi Karl,

You're right about the saddle to form-fit the tubing. I don't use a saddle, but more of a "cradle" with less surface area - I either pin the tube or tighten the u-bolts until the tube starts to flatten slightly. The flattening makes it hard to turn. Heavy wall aluminum doesn't seem to mind it. A saddle would surely help and I will add some if this solution doesn't work out.  

I think the problem I am having is due to the wind swinging the boom. This twist causes other things to move in other directions. By adding the second strut, the beam won't sway horizontaly nor twist longitudinally. I finished the three sidearms tonight and will give them a try tmw. I added a hole to put in a boom pin if needed later. I'll post some pics tmw of the new arms and hopefully the installation - if it's not too windy up there tmw.


Frank - Hope the JN recovers OK. At least it was in the line of duty... ;)

T

Well, built the three sidearms last night and installed the bottom one today.  I made a few mistakes and had to climb up and down three times... :-[

Anyway,  after installing the first one I found the Yagi is rock solid now. It is anchored into the tower on all three legs and does not move at all like before.  I think this will do it.  Tmw I'll go for the gusto and do the middle and top Yagis.

Shuda done it this way from the beginning... ;)


In the pics below notice the sidearm that anchors to the two tower legs. It supports the weight -  along with the overhead trussing.  The new sidearm that goes from one leg to the boom helps control side-to-side rotation and boom twist.  The sidearms pictured are made from 4" X 3" angle steel, 3/16" thick.  The big u-bolts are 3.5" using 1/2" threads.  The smaller ones are 2" using 3/8" threads. All stainless, of course.

The 36" sidearm, already installed, was a heavy one to haul up. Tied it to my belt and climbed....

I feel much better already...

T

Well at least it wasn't 20 feet long looks much better now.

Tom, Just got 2 elements flat side down 20 foot spaced to work in simulation. All it needed was a 1:2 turns ratio transformer at the feed point. This gives me a nice VSWR across the band. A tad less gain than HUZ around 9.8 dBi and similar FB but it plays across the whole band. Now to figure out how to swap the pattern. I'm thinking a pair of 200 ohm feed lines to a relay. This might also work with your 80 meter loops. Imagine pulling the bottom up flat the increase in average height if it works. I was getting about 175 ohms at the feed point.

Yep, two loops on a 20' boom is FB.  As I posted earlier, do the "extended base" on both loops for higher avg height and switch the stubs with a relay. It's a proven system and simple.

What kind of feedline do you plan for 200 ohms?

Just got off 75M DX window. (10:30PM)  The static crashes were 35-40db over. Called CQ and worked about 7 Euros - but decided I couldn't take any more ear abuse and went QRT.... ;D

T

Tom,
just got it. two loops about 12 feet tall with 28 feet of 200 ohm feed line. Switch between drive and a short to reverse the pattern. Drive a 1:2 turns ratio transformer. This would put the relay box about 20 feet up the tower.  Feeder could be 200 ohm open wire line. 50 ohm cable to the box with a QRO 1:2 transmission line transformer. I think I will start with a single direction to see how it plays. Under 2:1 across the band

That should do it Tom!  Heavy duty rules!

73,  Jack, W9GT

Yep, now you're talking.  

200 ohm openwire will be spaced pretty closely, but shud work FB.    

Sounds like a cross between a broad banded folded dipole and a loop.   You shud get 20db+ f-b no problem.

T

Agree but simulation does not show that kind of FB performance at any angle of radiation unless I go to 3 elements. 200 ohm stubs and feeders should be low loss.

Using 2 el deltas on 40M, Huz is seeing 20db++ into Eu and my 2el deltas are seeing 20-30db f-b on 75M.   A 2el delta loop is roughly equiv to a 3el dipole Yagi in f-b and gain.

That makes sense.  Seems like I recall that the rule of thumb regarding quads vs yagis used to be that a 2 element quad was roughly the same in performance as a 3 element yagi.

73,  Jack, W9GT

The loops can equal the front-to-back (F/B)ratio of a three element Yagi, but will have a db or two less forward gain.

The modeling on my loops shows a little better than 30 dB F/B at 30 degrees elevation.

What's the Spacing between the driven an reflective elements.

73
Jack.

Huz, I think you have a better FB because flat side is up so higher overall height. My simulation shows best FB at around 45 degrees. I'm a little concerned that stuffing 3 loops on a 20 foot boom may end up a bit weird.
Two elements with a 10 to 15 foot tall loop fed at 200 ohms may be a better way to go. Need to work on the FB simulation to see if I can dial it in. VSWR is great and that is when I hit the sack last night.

You see that much difference in modeling?

I usually saw about 11.5-12 dbi gain for a 3el Yagi 1/2 wavelength above ground  -  and about the same for a 2el delta loop with its avg height = 1/2 wave above ground. (Same boom length)   I wonder why you are seeing 1-2db less?

Maybe Frank, you aren't seeing the high f-b you wish cuz the average height of the loops is < 1/2 wavelength high. As we all know, the pattern tends to get lazy looking when < 1/2 wave high and the f-b goes to hell.


Just got down from a 190' climb. Got the other two sidearms installed. The Yagis are the equivalent of being WELDED to the tower. I'm loaded for bear and ready to kick ass tonight on 40M. Hear that Huz?? You getting on so we can hold court in the static?...;D   Frank, will you have something to use tonight?


Jack/GT - How's that 2nd loop working out for you?

T

Tom and HUZ

Been working....no time to work on antennas this week.  Its supposed to rain tonight and tomorrow...we will see.  I hope to get something done, perhaps Sunday.  Might even try just supporting both from single top support and spacing out 20 ft at bottom.  I will listen for you guys tonight if I can.  Still on one loop (1.4 dBd gain or something like that).

73,  Jack, W9GT

The plots I posted below show a little over 10 dBi. You were seeing 11.5-12 dBi for a three element Yagi.

Quads do not have any "extra" gain when used as an array. The stacking gain obtained by a single quad loop over a dipole does not carry through in an array. With a single delta-loop, there is almost no gain compared to a dipole, so there would be even less of a reason for them to have "extra" gain in an array.

I'll be on early.

I'll have to look at my model again.  I always thought the 2el delta was a good trade-off using one tower vs: a 3el Yagi, etc.

Anyway, I'm going grocery shopping now, so won't be back until at least 8PM. See ya on after that, OM.

T

Just dialed in the antenna. dipole driven, loop reflector. VSWR flat at 7.150 with less than 2:1 at band edges.  US stations weak but just got a 59+10 from an IK6 and 58 from RN3ZDD running 100 watts. I should be able to get on tonight but a bit after 8:00.
I want to simulate the antenna I have. . The loop reflector is about 35 feet tall and about 150 feet of wire. I'll change it to a driven loop if I can get a good match.

Running 100 watts on a low angle night with Tom Vu is like putting a 30 dB pad on the radio, but it was a good test.

It was a fun night with Jack / W9GT  joining us earlier.   Much later after you signed out Chuck/ K1KW stopped by for a coupla hours.   The highlight of the evening was working a MOBILE in Iraq who was delivering the mail to the US military bases. He was on the road in an 18 wheeler in a military convoy... ;D   59+20.    The band was in the best shape I've heard in a long while.   

Keep up the antenna experiments, Frank.


What happened to the Huzman?



T

THat mobile from Iraq was a kick  ;D

Some guess meter readings - when you were testing the low dipole, S9+10 on the yagi, about S-5 on the low dipole.  Chuck was about S8-S9.  So tonite u win over Chuck.

I gave a call when you paused for QRP but some 10 watter in G-land strapped me  ;D

Those beams are really working for you Tom!  You were copying stations S-9 that I could barely hear.  Had lousy high noise level here as well with the rain in the area.  Frank, you were 20 over here, then you just disappeared.

73,  Jack, W9GT

Jack you also faded way down. Most US starions are pretty weak. I'm going to add a second loop as a driven element today to see if I can reduce the noise. (if it doesn't rain) Many of the weak stations Tom worked were buried in static but in there. So as HUZ says, it is all about signal to noise ratio. The high angle attenuation only looks good with corner fed loops but I can't seem to get any good FB in simulation.
Last night I could see me getting in the way so decided to do some simulations.
TNX  for the help testing. I was good until the band went way long.
 

Hi Johnny -

Aw, too bad we missed you again. I must remember to pause specifically for YOU next time. I'll bet you wuda made the trip last night.  What callsign will you be using, something like "SV1/W3JN?"  That American Iraqi-mobile had a small whip and simple 100 w transceiver in his truck. He used the call YI9SLI - his home call is KB2SLI, so they obviously let them use their own suffix. I found a picture of him and posted below.  What a thrill.  (I was tempted to axe him about road landmines, but decided not to...   :o)

Frank, you shuda hung around later on - the angles started to go higher and Chuck's single Yagi at 50' was par with my stack into western Europe after about 10PM or so.  The farther middle east still showed a difference at times but it was less as the night went on.  I think the angles appear to be very low early on and slowly move higher throughout the night. That's the way it used to work on 75M in the past too.

Last night's results showed me the value of maybe putting in that 180 phase switching to get some energy up at 30 degrees for these special times.

Frank, now you have a baseline to improve on. I intentionally picked out some weaker stations to see you stretch - as well as some louder ones to get you some reports.   If you work on the system there, you will slowly get that S/N ratio improved. I saw the Huzman get to the point where he can hear about anything I can hear now, so it's just a matter of trying many things.  Get that beverage up as soon as you can too. I think Steve relies on his bev most of the time. Many times a TX antenna is not a good RX antenna. Though, I find my stack is at about par with the phased bevs on 40M, so I use both in diversity. However, last night for a while, the stack was MUCH better than the bevs, so I switched off the bevs for an hour or so.

Jack, OK on the cold there - hope you feel better. I think you will see a massive difference when you get up the second loop and generate a good f-b. That is the fastest way to improve your s/n ratio. After that, a bev will help.  I understand you had storm static over there - it was not bad here at all last night - one of the better nights in a long time, static-wise.

Hope to get on tonight. Might also try 75M for a while too.

It really was a lot of fun last night with many personalities dropping by throughout the night. I even heard someone going , "yallo, yallo" in the background a few times... ;D

Later -

T

Tom,
I found a set up with two loops that will match 50 ohms. I will be heading out with a spool of wire soon. I think the Hot Rod Racal will end up on an RX antenna. It is a quiet radio and would work nice on a beverage. I'm hoping a loop driven element is quieter on RX. TR7 is not the quietest radio. It has a jumper set up that would allow using a different RX or a splitter would allow two receivers.
I know you were reaching out for the weak ones to make it a good test. I was working Russians earlier and a couple italian stations when the band was higher angle. Then I took a break and listened to Chuck.
I will be taking Peter to his game tonight. He can't play but he will help out. I might get on early.

SV0/W3JN

That was probably me doing the "HAY-lo"  ;D

John,
You can get a nice low angle of radiation with a corner fed Delta loop flat side down if you can find a single high support. Time to build another loop, it is raining. 

Yeah, I think it WAS you!  It was more of a "Hay-lo" rather than "Yallo" said maybe 3-4 times and that's it. If so, you were about 5X8 and an easy copy. With that signal it wuda been easy last night, but difficult on a noisy static night.  If we're on that late tonight on 40M, (11PM local)  I'll give a few pauses for (SV0/W3JN).  Make a tape of it if you can.


Frank, you might as well go for the gusto - use two Racals and go dual diversity RX right off the bat, once you get the bev going.

T

Rain just letting up so ready to pull up the driven element. Sure I could do diversity. It would be cool to find the interface between receivers to make diversity control the two AGC loops. Cubics have stereo outputs so could use the tiny brain....ah rain stoped

Gosh Steve.....we wuz havin' a good time until.........................I guess we landed on "their" frequency.    Great fun workin' the Europeans tonite anyway!

73,  Jack, W9GT

Jack You were pretty strong here tonight. A  line of thunder riding over us tonight so no radio for now.
The loops seem quiet compared to last night and a dipole driven element. need to trim about a foot off the driven element. It resonates at 7050 but works on 7.15.
I'll run it like this for now and maybe put up a reference dipole Sunday. I have a tall tree about 60 feet behind the reflector. Humble 100 watts will get old fast.

You were really getting around tonight, Jack!  Heard ya holding court and then calling DX stations. Not bad.

I just got on 40 and had a good pileup going, but then the T-storms came. The rain static (from the pouring rain) wiped out the Yagis with +50 over noise. I could still hear on the bevs, but even they were impaired. Now I hear thunder.  If it stops, I'll be back on. Corndix were great tonight with reasonable static and good prop. Not sure why the static crashes aren't worse, but won't complain..

Was hoping to give Johnny / SV0/W3JN a call tonight. He will definately be heard. Maybe after 11PM.


Frank, better model that reference dipole. At 60' behind the reflector it will produce a small f-b into Eur, unless you put it at right angles. But then it will have a big null off the side instead. See what it looks like first.

T

I'm running a simulation of a 3 element loop with the reflector behind the tower 60 feet away. Impressive FB numbers coming up. Never got back down to the shack. Steady stream of storms here.

Didnt hear you on tonite, Tom, but I did hear the HUZman holding court on 3770 working the pileup in your honor.

I had T-storms come thru until about 12 midnight. Got on 40M afterwards for an hour and paused for you a few times. No JN.... ;)


40M dropped out like a rock - down 30 db in minutes.  I moved to 75M from about 1AM to 3:30 AM local. Worked a pileup calling for QRP <10w for the duration. Lots of fun to give the PW guys a thrill.  No JN on 75M either... ;)   We'll try again.  It wud be nice to do it with your spy special b4 the package arrives wid the big guns.

T

You must have had your EU ears on. I called you several times on 40 and 80.

Yeah...HUZ and I were having a lot of fun, but encountered a "reserved" frequency situation and it kinda disrupted the flow.  Noise level was still high here, so it was a challenge to hear the weak ones.  Ian, GI3DZE had a truly outstanding signal.  up to 30-35 over 9 here.  Lots of good sigs last night.   Also South Americans were rolling in.

73,  Jack, W9GT

Interesting on the "reserved" freq.  Actually, as crowded as 40M can be, I'm surprised we don't have more scuffles over moving in too close. I notice Steve is able to pick a freq and start working 40M without complaints 95% of the time. Over maybe 20 tries to occupy a frequency, I've had only one guy say there was a net on freq where locals were too PW to hear. So all in all, it's been pretty good.   I even axed if the freq was in use last night and a very faint local W1 came back and said he was using it for a contest but I could have it now.  Good relations.   BTW, I usually axe at least three times and switch antenna directions each time.

Yeah, Steve,  as the winter comes on it will be more difficult to hear each other. I can barely hear GFZ most of the time now. So we will need a signaling system as I mentioned in email to alert when we want to break in. The f-b, Euros and skip conspire to hear dick off the back.

I'm stilll recovering after holding court til 3:30AM last night on 75M. That's the latest I've been on in years and heard the sunrise peaks through most of Europe. The Germans were on there a good hour into their sunrise and still very strong.  

Also worked Jordan, Quatar, Israel and Saudi Arabia - no Iraq.  It was almost a middle east clean sweep.  Haven't spoken with anyone in Iran yet.


T

Forty meters was good all along yesterday. I heard eastern European signals as early as 3PM local. The VKs were booming about an hour later with VK3EW peaking out at about 20-over in the late afternoon. Static was worse earlier in the evening and then quieted down. By European sunrise, the band was almost dead quiet. Cyprus came through quite loud as you can hear in the attached file. The guy was running a home-brew DSP based rig.

Eighty meters was pretty hot too. You can hear how loud the EU AM stations were in my other post. A few loud static crashes in there but not enough to cause any problems. I even worked a German mobile station later and a station in Crete running low power was 59+10! I also had a nice half hour chat with a German station that also runs 10 meter AM.

I primed the EU AM stations to get on 40 meters too. It should be even easier to work them on that band. I spoke with a GI station a few days ago and he's working on an AM rig to put on 40 meters too.

This winter is going to be fun.

Loops almost dialed in. Ends up at least 25 feet up from about 15. Just need to trim a little off the reflector. I trimmed both elements and had the most effect shifting frequency changing the reflector. I'm at 7.05 right now and antenna takes power well up to about 7.2. Still a good match at 6.9 MHz. I suspect the tower and guy wires may be effecting the resonant frequency a bit. Once I have it where I want I will try stub switching.
I heard VKs around 4:00 but they were weak. EA7 was working them.  hope to get on after 8:00 and see what happens.
What a beautiful day in CT.

Frank,

Now use some reference antenna to A/B test the f-b up and down the band. You want to see max f-b around 7150. Use the W4's in NC/TN, etc. Trim that reflector for max f-b regardless of swr. THEN adjust swr by adjusting the driven el and the matching scheme. 


Jack/GT - I just did a quick sweep of the 40M band and heard you working an Italian with your NEW 2el loops. You were the loudest I've ever heard you at 59 +60. That's Radio Moscow level set on a good night using the stack!   Nobody hits +60 except maybe Huz and and a few others on a STRONG high angle night. Time will tell, but sounds like it's really working.

How high are the loops, config and boom length again?


Hope to get on later tonight, maybe after 8PM too, and work some. Look me up, guys.

T

Yup Jack, I would like to know what you did.
Tom,
I didn't put up a reference I thought it better to concentrate on getting the ends higher so shot some lines over trees to hold up the ends. I figure I can use the 80 meter dipole in the woods as a reference for now. Simulation showed it screwing the pattern as you thought.

Well, that was fun. I found the TR7A works better in pass band tuning mode. seems like I hear a bit better than TX as I look at the QRO chassis and imagine how easy it would be to reassemble it. I figure about 20 hours would get it back on. It needs to get a little cooler out to run that again. Loops seem more quiet compared to the Dipoles and making them 10 feet higher must have helped.
I need to fire up the HPSDR rig next..

Good stateside group in there tonight.

Yep, you did surprisingly well tonight on 100w compared to the first time a few days ago.   You worked a few Russians with us and even called CQ and picked a station out for the group.  I think that delta loop driven/ref combo is going to be the best one for you.  Next get up that beverage while you can. You will find it hears better than the deltas. Then add the linear and you're smokin'.

I think we stunned that UK station - after he gave my signal report I axed him if he was using an analog S-meter or one of those homo-type LED S-meters. There was a long pause and then said in British accent, "Ahhhh, could you repeat that please?"   ;D

It was QRP Night for us. We called for and worked maybe 85% of Euro/Russian stations that were 10 watts or less. There were plenty of them too - enuff for many hours.  

Working Bahrain for the first time on the new 40M was one highlight of the night for me. Still looking for a middle east clean sweep.

Jack/GT was in earlier and has definately improved his TX and RX with the new diamond loops.

The HUZ was hearing better than ever tonight. It's gonna be a real challenge for you to catch up to him, Francis.

T

Lots of fun tonight and many funny moments. One guy asked if he could have my call. I said yes, but only if he gave it back. I heard someone laughing in the distance when a belch was let loose on the frequency later. Then we yukked it up about the QRP and QRPp stations, disconnecting antennas, QRT stations, etc. The DX crowd probably thought we were drinking.

The band was VERY quiet tonight. I'd say it was the least QRN I've heard since March. There was some early on when Jack and I were working the VKs on the long path, but later there was none! The only station I struggled to hear was A92GR. His signal got stronger as we spoke and by the end he was a nice Q5. We must have worked 10-15 QRP stations (10 watts or less). The one guy was only running 6 Watts. Several had homebrew rigs. Cool. Other than working Bahrain, working 9K2MU on 10 watts was the highlight of the night.

This winter is going to be very interesting.

Tom, Steve, Frank....

Yes, great fun last night.  I agree that the loops are working, but I think they will be much better when I get them adjusted and optimally aligned with each other.  I was under the wx with a cold this weekend and the rainy cool wx wasn't conducive to doing much ant work Sat.  I got outside Sun afternoon and hurridly hoisted up a second loop that is approx. 5% smaller than the driven element. It is presently working as a director, although I can change things around and move the driven element to the other side, so the second element will be a reflector.  The top of the loops are at about 75-80 feet.  They are diamond-shaped and I am feeding the lower corner of the driven element thru a matching section of RG-11U.  The top corners are presently only about 6 ft. apart and the bottom corners are stretched out to about 25 ft. apart.  The orientation is such that they are pointing (at right angles to)approx. 60 deg. E of N.  My tower is 86 ft in total hgt including a 4" mast at the top and the tower itself is quite large in cross section (38").  I'm sure the tower has some effect on the loops, but maybe not in a negative way.  There are lots of old radials in the ground radiating out from the tower base in all directions.

I don't have a modeling program...so if it would be possible, maybe one of you guys could put it into your program and see what it looks like.  I plan to eventually install a 20 ft. boom at the top and uniformly space the loops from top to bottom.  I will change directivity by switching an additional stub in and out to change from director to reflector.  Perhaps, varying stub length and/or feeding at different phase would allow moving directional pattern around the azimuth to some measure??

Anyway guys...sure enjoyed the party.  I hope to throw about 300 ft or so of wire out through the woods for a beverage...should help things on the receive side.  I may need to build an additional outboard preamp.The noise level is very high and it is a challenge to hear those QRP stations.  I did hear the DL that was running 10 watts and also 9K2MU when he was at the 10 watt level.

Thanks Tom...for the Radio Moscow report!! HI Hi FB OM.  I'm not running excessive power...just legal limit with a pair of 3-500Zs in one of my home brew amps.  I call it an SB-220 on steroids.  It has a very husky power supply with 3-4 KV using an old BC xmtr plate iron.  The trusty IC-765 has always been good on the rcv side and has pretty good audio on xmit with compression cranked in in the 'DX mode".  

It is fun to watch the totals on QRZ while I'm on 40 and watch the total views go up by the minute.  Obviously, I'm being heard.  

73,  Jack, W9GT

Jack,
I'm finding the element lengths need to be shorter than simulation. I found the same thing when I had a quad up years ago. I suspect due to the tower. Director seems similar results as a reflector in simulation. I'm considering swapping pattern by tuning the reflector to a director. I would think you would get higher average height if you changed to a triangle. I hung a vertical rope off the apex to support the coax to keep it from drooping.
At 80 feet that must really play. I noticed performance shift raising the bottoms yesterday. My triangle loops are about 30 feet tall so bottom is 25 to 30 feet above ground. I didn't need RG11 to get a good match at 20 feet spacing. Right now I'm under 2:1 VSWR 6.9 to 7.2 MHz. Elements are 147.5 for reflector and about 135 for driven element. I know the reflector is long because I cut two feet off the driven and CF didn't shift much. I got a good shift cutting 2 1/2 feet off the reflector and need to do it again to dial it in. May need to put a couple feet back on the driven. Once I dial it in I will replace the JS wire with some fresh #10. 
Yes, I also need help in the RX department but loops are quieter than dipoles.

Frank,

I wud stick with reflectors for loops. The director does not work as well by a long shot when modeled. It's OK on Yagis, but not for loops.  Use HUZ's relative stub dimensions and you will be in the ballpark.

Here, I use an 11uh large coil across the coaxial stub that I can precisely tap. Once I set the f-b in one direction, it was the same f-b in the other direction using relays to transfer the loops the other way.  I see 20-30db f-b in either direction. (These are the 75M loops, of course)

I don't think the tower has much effect on the loops. At least from modeling memory it was a essentially invisible unless you have guy wires that are close to resonace. The tower itself shud have no effect.  Just tune that ref for max f-b, no matter what it requires, and you'll be fine.  The acid test is switching it on W4's (or Euros) off the back and seeing 20db+ f-b. Everything else is guesswork.  Remember that the swr tuning comes last - after the f-b has been set. The matching will have little to no effect on f-b.

Jack, you were doing well to hear Kuwait when Murtada was running 10w. I think the band has been starting out low angle, later moving up to higher angles by 8pm, and then dropping down very low again later in the night. It seems to be going thru a transistion now - maybe wintertime corndix are coming in, I dunno.  It constantly changes character, which keeps things interesting... ;D

T

So you have both loops tuned as driven elements and then add coax plus some L to make them reflectors. Question. Why did you need to use the inductor. Was it just easier to dial in than snippling coax?

I don't know of any guy lengths that are close to ham bands. Tower is long for 40 7 sections with the mast + antenna.   

My tower guys are broken into non-resonant lengths, however one of the middle guys actually passes thru the plane of one loop.  Frank, the problem for me in going to triangles is real estate.  I can't tie the ends far enough out for the angles.

73,  Jack, W9GT

Jack, I know the problem. The corner of one of my loops is in the leaves of one tree and just fits. I also ran two ropes between loop corners to hold the spacing constant. I'm close to a guy wire at the bottom. I could see how your configuration would put a guy through the loop.

Even if a guy wire is 40' away, if it is near to the length of a reflector, director or driven element, (in length) it will cause a "divet" or worse in the pattern.
It's more a matter of length, not proximity  on 40M in the real tower whirl. Its effect will change as it is put square or at right angles, of course.


One thing to be aware of is the length of a guy wire is actually effectively slightly LONGER due to the insulator end capacitance. (Johnny ball insulators) Chuck once measured this capacitance and adjusted the lengths as shown on the ARRL table. I did the same here and found it required a foot or two shortening, depending on freq,  IIRC.

Anyway... Jack, I use two identical loops spaced 40' apart. (for 75M) Each has a coaxial balun at the feedpoint and a 70' RG-11/U coax run to the tower. I feed one and the other gets an inductor across it to tune as a reflector. The relay then swaps/switches the connections to make it change directions.  I cuda used an open or shorted coax stub instead of the coil, but  wanted to be able to use a test beacon and climb up there to adjust the f-b manually with precision.

T

Couple of questions Tom....do you use 1:1 or 4:1 baluns (or something else)?  is the coil at the end of the RG-11 section?  Do you cut the RG-11 for 1/4 wave at operating freq (considering vel factor)?  I would guess, as a matter of scale, then my proposed 20' spacing would be fine for 40M.  

My tower guys were cut with vel factor of galv. guy line and addtl cap on ends considered, however, there are some series effects due to the cap across the insulators and between the sections.  Phillystran would be the best solution, but it is expensive for the size I need (equiv of 5/16" EHS) 11,000lbs.

73,  Jack, W9GT

Wow Tom, That is a long coax run. I could get into the shack with about 50 feet of cable on each loop. All I would need to do is replace a basement window with a lexan panel. Then I could dial it in from the operating position.
So the balun plus 70 feet should be close to 1/2 wavelength electrical of about 80 feet of RG11. My old quad was very close to 50 ohms at 12 feet spacing on 20M so didn't need the quarter wave stub. I did need it on 15 and 10M though. I'm getting a good match directly to 50 ohm coax at 20 feet spacing.
Jack I think Tom is using 70 ohm cable to the shack.
Jack are you feeding the top or bottom?

I'm feeding the bottom corner of the driven element and shorting or stubbing an addtl length across the bottom corner of the parasitic element.

73,  Jack, W9GT

Jack,

This is for 75M:

I use a simple 16 turns of RG-11/U  (1:1 balun) wound on a 4" ABS plasdick pipe.  (Same technique for the 40M Yagis) The "stub" coil is a real coil, 4" diameter using silver plated edge wound stock - low loss.  The stubs were cut to 142 degrees including vel factor. I had originally wanted to use a remote vac variable, but the tests showed I needed inductance instead. After winding the balun, I was short coax to the tower so just used a coil - all the same in the end as long as you can tune that reflector for max f-b.

Frank, 70' of coax is not that long on 75M, just like 35' or so on 40M.  This includes the balun turns. It's only about + - 20' to the tower from the eles on 75M. Yes, I use 75 ohm hardline buried underground to the shack. The run from the tower alone to the shack on the 2x2x2 stack is about 440'. This doesn't include the hardline run up the tower and the phasing distribution lengths. I don't sweat loss of hardline at 7mhz. The TO angle is the most important thing  - even forward gain is no big deal.  Running a long feeder to get away from the house noise is another good trade-off.

Jack, I know some guys use and like Phillystran, but I wud never use it here for a tall tower. I stick with steel all the way. I sometimes use Philly for critical VHF boom trussing and and wire array supports. It's good to have an invisible support for other antennas in the area.

Hope to get on 75M tonight - as well as maybe a short 40M session. Maybe we'll see ya all there.

T

Yup, this weekend I changed the 30 dB pad in front of my station to 20 dB.
If I use HUZ stub length I could do switching at about 15 feet on the tower.
I suppose I could mount a water proof box for relays. I want to keep my losses as low as possible. I'm thinking of a twisted pair for the stub. maybe Teflon wire rather than coax. I bet that #12 teflon we bought is under 100 ohms Z.
 

Yes, a NEMA box on the tower will be FB.

JJ killed me on 80 tonight. I could hear FB but was PW on TX most of the time. Some pretty interesting stuff was worked. I'll let Tom tell you about it.

Yes, fun session tonight on 75M. Very low angle as shown by the reference dipole comparisons. A number of celebrities stopped by.

Don't sweat the TX part, Steve. Guru Trogladite says it very honorable thing to hear much better than transmit.  Just like rat dog with large ears and tiny mouth.... ;D  TX easy to improve - RX vely hard to make better.


Here's the highlight of the week. Sri Lanka called in on 75M. It took me a couple minutes to get his call and info, but it was worth it. I didn't realize at the time Sri Lanka is a large island SE of India, about 8600 miles away!  The heading is about 33 degrees, right thru Europe, so the delta loops were on the right path:

4S7NE
Nelson Ranasinghe  18 Katana Housing Scheme  Demanhandiya 11270, SRI LANKA


Steve, after you  left I got a call from an older Russian near Moscow. He said that my FT-1000D was a museum piece. He had one too and was just joking  - cool guy.  He talked and mentioned "kilocycles" a few times I told him HE's a museum piece since he still says "kilocycles. That was one of the first times I heard a Russian crack up and laugh out of control on the air... ;D  I told him they haven't made FT-1000D's since the Berlin Wall fell down.  It went on like this for 10 minutes. That was the funniest QSO I ever had with a Russian station. They are usually very serious with westerners.  I'm gonna work over a few more and see what happens... ;)

T

I drove the simulator after football last night. I have a working switched stub with good results but the stub is shorter than Steve's. Maybe due to my simulator skills in loading coax but anyway it seems to play. Only about 9 feet in length so swinging it to the tower could be a problem.  Sounds like you had a ball.

Your suggestion to add a 1/2 wavelength extension to the 9' stub coax to bring it to the ground for tuning will work FB. I wouldn't worry about stub lengths at all. Ya gotta eventually get it to the shack somehow anyway - might as well be partly stubs and feeders.  Just remember that Tom Vu has over 600' of total feeder to the stack but can still hear a pin drop in Eu...  ;D

Yep, we did have a ball last night.  You never know who's gonna call in just like Forrest Gump's box of chocolates.   Last night Steve said it's like fishing - sometimes you hook a marlin, but most of the time it's blue gills... :)

I'm still happy about that Sri Lanka marlin last night.  That was the first one ever on 75M for me after over 25 years of DXing on that band. The path wasn't the homo-easy type like working the VK's at sunset.   It was at 10PM going through Norway,  Russia, a tip of western China, around and down over the Himalayas, through India to Sri Lanka. Cool stuff! Lots of northern attenuation and if he was only 3db weaker I wouldn't have heard him at all. Right on the threshold of my hearing here and I love those types of contacts.  So, I'll just turn the notebook page, bury the entry in my notebook and lose it - don't need no stinkin QSL - I know I worked him and that's good enuff... ;)

We'll see what the next few nights bring.

T

Where are you feeding the loops Frank?

I'm feeding them in the center of the bottom. I don't see any advantage in running coax up to the apex by simulation. Any suggestions? As I said my loop size is very close to yours. I don't have the numbers here at work but the bottom is slightly longer than the sides.

OK. So you are going with horizontal polarization.

Yes, the top or bottom feed doesn't seem to make much difference.

I wonder if the varying length of sides vs bottom of a delta loop, or making all sides equal in a square or diamond makes much difference?  I recall seeing an article about a rectangular loop with long top and bottom lengths vs much shorter sides. (sort-of looking like a big fat folded dipole).  I have seen all sorts of loop configurations, even circular elements, but I'm not clear on how the shape affects the pattern.  I believe that the polarization is determined by whether you feed a vertical element or a horizontal element, however, if you feed a corner of a rectangular loop, is it still horizontally polarized?  In my case the elements are square, but tipped to become a diamond shape.  I feed it at the lower corner of the diamond.  Loops are really pretty effective antennas and seem to be quieter than dipoles.  Many guys are using horizontal loop "cloud warmers" on 75 and 160 with decent results, at least out to several hundred miles.

I know my loops need to be optimized, but they sure do seem to work well on 40!  I wish I had the room to put up a couple for 75 or even 160.

Here's some more food for thought.  What about multi-turn loops?

73,  Jack, W9GT

Jack,

For 2el or more, I've found the most important thing with loops is to configure them to take advantage of the highest average height possible based on your supports. If you can put the flat side up, then do it. If you can make the base longer than the sides, then do it... both will increase avg height.

For array use, I don't think there's anything magical in any particular shape. I've used both quads and deltas on 75M and both kick ass cuz they're up high and have a great TO angle.... and they're tuned for max f-b precisely.

Sounds like your exisiting loops are vertically fed. I wud feed them in the bottom middle and go horiz fed- at least try it and see. If you see no diff, I wud stay horiz.  Use a reference ant and carefully compare them, of course, or you'll never see the diff just by getting reports day to day..

(Yes, the corner fed loop is vert polarized)

T

Used as a single element, the quad has the most gain of any loop shape, except for a perfect circle. The difference between it and a delta loop is supposedly on the order of a dB or so.

Multi-turn loops are a good design for small transmitting or receiving loops, but I don't see any advantage if you have a full wavelength sized loop. You may get some impedance transformation that could be useful in some cases, and if you were feeding the thing with open wire on multiple bands, it may be easier to match/tune.

I lost a good loop article when I moved to Ca. it was a study done by the Army right after nam where they tested a number of loop configurations and feed methods. One cool designs I heard about was the loop antenna in the tail of an F16. A GD guy told me it worked pretty well down to 6 MHz.

Jack, looking at simulation the input Z shifts around as the height of the loop changes and agree with HUZ there is only about 1 dB loss moving away from a circle. My loops are about 25 to 30 feet tall so the top is at 55 feet and bottom at 25 to 30 feet. This accepts 50 ohm coax feed with two spaced 20 feet. my 2:1 VSWR points are 6.9 to 7.2 MHz. Reflector is a bit long.  So I get my average height taller by making the loops shorter. I have a 3 element design that is only 15 feet tall and since it is closer to a folded dipole the input Z isn't bad. 10 foot spacing sounds weird but it sure has some FBOM front to back.
I can't make vertically polarized loops work. They have a low radiation angle but FB and gain stink. My old quad was configured as a diamond fed at the bottom it worked very well for 19 years.

The vert pol loops do produce a nice low take off angle. But usually, the gain is down so much that the horiz pol still beat it, except at the very lowest angles.

I couldn't figure out how to phase 2 vertical polarized loops and get it to radiate in one direction. maybe end fire?? It does have an interesting take off angle but around 6 dBi gain.
Weird WX here today, Rain, thunder and wind. I bet it notches things colder.

Good wind test for the 40M stack today.  Gusts 45-50mph - probably higher up at 190'.  The new sidearms did their job. No twisting or turning detected. The boom and el alignments still look perfecto.  

Amazing what a little steel placed in the right spots can do.  [caw mawn]


T

Phasing for the vertical feed would be no different than horizontal feed - about 135 degrees, plus or minus your exact installation. It's end-fire in either case.

Gee, you are right I just got the sim to run and it has a good FB. Only about 6 dBi gain but a nice lobe at 15 degrees. Everything above 30 degrees is attennuated.

If you want only low angles, it's the way to go. Probably makes a good RX antenna. All that high angle stateside stuff would be gone.

Hmmmm....

In a closely packed residential neighborhood, I think a vertically polarized lobe (15 degrees TO) will do more to warm the neighbor's houses and BA's than anything else...  ;D  Stick wid horizontal.

T

I agree. Other than possibly being better on receive, the loops up at about one-half wave and fed for horizontal polarization will beat the vertical polarized version.

It would be cool to dial the shape charge with delay lines....
I think my simulation shows a bit more gain at 15 degrees.








HUZ, Congress, with their cradle to grave benefit package

That was my thought Frank.  Seems like you could change the phase by adjusting the feed line lengths to each loop to adjust the pattern around the azimuth.  Don't know how much variation you could achieve, but would be an interesting concept anyway.

73,  Jack, W9GT

Jack it all seems possible till you consider that pesky ground under the antenna. I have tried by putting the delay line length as a variable in the simulation. I think I will start with 2 1/2 wave feed lines to get me to the ground and then play from there.

In the end-fire configuration, changing the phase will only change the gain (some), the F/B (potentially a lot) and the exact location of the null on the back side of the pattern. That's it. You cannot change the azimuthal angle at all. You can possible change the width of the azimuthal lobe slightly but not much.

I see no value in changing the phasing in the shack. The longer the phasing lines, the more reactive they are, the less the bandwidth and the greater the loss. If you want to null stuff out on receive, use a second antenna and a phasing box.

Just worked Mohammed / A71EL in Qatar at 3:30 PM local. He was about 5X7.  THREE hours before our local sunset.  Looks like 40M is opening early today.


Interesting thang is western Europe  appears to be medium-high angle at this time. There is only about 5-10db between the stack and low dipole on most western Euro - it's usually 20-25db at optimum times.

However, Mohammed was not copy-able on the low dipole, so mideast was probably low angle at 3:30PM.

T

Steve I need to play with the simulator some more to make sure the stub is 9 feet which would put my switching 30 feet up the tower. I was just dreaming about variable phase doing anything constructive.

I'm thinking 40 might be open for DX 24 hours a day in the winter months.

Ah brain feels good. Got a stub switching system like the HUZ machine to work with my configuration. RG11 off each loop 19.05 feet down to switch. Add 8.25 feet with end shorted for stub and drive the other. This gets me down close to the ground by flipping the long section with the short. Flat side down doesn't show quite the FB but that is life.

We all KNEW you'd finally settle on this config... :-)  It will work the best for you.


Yeah, Steve, 40M may never close to Eu, just like the all night roach motel.  I'll bet come Dec 25th you could hold a QSO with the G's right thru OUR local  sunrise into the afternoon.  It will be interesting to catch the Euro sunset for the first time. (At least for me)     Maybe 11AM local or so wud be the time to do it about that time.  I know that VE1ZZ claims to have done it on 75M from the VE1 Atlantic coast.

T

Kewl beanz Frank. I love it when a plan comes together.

Things started to jell when I got home yesterday and lopped another 2.5 feet off the reflector. Resonant frequency came up another 50 KHz but the VSWR minimum came off 1:1. So this was telling me I needed a different feed Z away from 50 ohms. I started with the two loop sizes and tried 50 ohm stubs which didn't give me a good match. As soon as I changed to 70 ohm the sim would tune flat. Loops want to be about 27 feet tall and slightly smaller than HUZ design. Actually ended up close to my present driven element size.

Just for grins, I decided to feed the second loop last night in a phased config.  Used a 33 ft sect. of RG8 to a tee.  The band was really hopping, so hard to really tell if much, if any difference.  Almost seemed like antenna was bi-directional.  Worked some Carribean stations, and several Europeans with good sigs, then 9K2YM called me and about scared me to death with a 20 over signal!  He was really booming in and he has a video link set up on his QRZ page to see his rig while working you. Great fun.

73,  Jack, W9GT

How did you come up with 33 feet for the phasing section?

34 feet close to 135 degrees. I also heard that guy last night around 6:00 Local and he was peaking 20 over. I have not tried to force feed the loops but had a crappy match with dipoles. I think if you have a long coax run the losses suck up the gain. I found my phased inverted Vee on 80 demonstrated good FB when the pattern was swapped but the reference dipole was stronger.

I heard you in there holding court, Jack.  I tuned in when the 8P? Caribbean station called in and then the KB4's looking for signal reports.... ;D  Afterwards you were working Euro quite well.

Strange thing is when listening on the beverage, I cud hear the Euros you worked FB. But when I switched to the stack, there was a Mideast BC station covering up the Euros on 7145?   All I cud hear was you, barely.  It seems the stack has much more low angle than the bev AND the mideast was obviously coming in low angle.

I thought maybe the RX had an image problem, but found the same results on two other RX's.  Steve said he wants to work tandem wid me when this happens... HA!


BTW, I'm working on my second quad MRF-150 FET linear amp module. Gonna combine the two for 1200W out, all solid state. If it doesn't fry, I hope to have it running maybe today or tmw. Instant band switching with 1KW is cool.  I'll post some pics of it later.
T

Tom, It might be a good idea to mount some large beer can caps near the amp if there is some distance back to the power supply. That switcher is rated for 35 amps so it should handle the extra load.

135 degrees per previous discussion/suggestions, 66% prop velocity.  I made it a little short to make up for connections.  Very crude and not anything all that precise, by any means.  Just fooling around with some concepts.  Certainly didn't see any earth-shattering results, but SWR went up, as expected.

73,  Jack, W9GT

Bear in mind, 34 feet will only be near 135 degrees when the SWR on the line is 1:1. I doubt you are getting anywhere near a 135 degree shift on the loops since their feedpoint impedance is far from 50 Ohms.

Unless you placed the phasing line after your impedance matching stub, then you should be in the ball park.

Jack you need to add a transfer relay so you can flip the pattern and see what it really does.

FYI, I was looking at an RG11 spec that said the VF was .75. I'll check again in case there is a foam version. Hope to do some antenna work today after the lawn dries a bit more.

Frank,

Are you combining the phasing section and the feed matching section in one piece of RG-11 or what?  I was using the matching section on the driven element and a phasing section of RG-8 from the tee to the director.   I know it is a mismatch, but works.  If you use two matching sections of RG-11 from each element to convert the ~100 ohms to 50 ohms, you end up with 25 ohms at the tee??  I think it stopped raining for awhile, maybe I can get out there and play with the antenna today.  Yes, I will use a relay on it eventually...perhaps the original arrangement of just using the second element as a parasitic element and switching from reflector to director is the best (easiest) solution for my situation.  I just like to try different things and experiment, hardly could be considered optimized at this point anyway...but I continue to get good reports.  Still need to improve the receive side...they hear me well, but it is a challenge hearing those 100 Watt or even 10 watt stations on vertical antennas that come back to my CQs.  8)

73,  Jack, W9GT

There's two versions on RG-11/U.  The polyethelene? version  is .66 VF. That's the stuff I got and believe it's called 11/U.

The other is the foam, .78 VF  and is simply RG-11 or something like that. Stay away from the foam cuz of the power handling and the extra coax needed due to the VF. (assuming you don't need the extra length)   The foam is actually a tenth of a db better in loss IIRC.

I used two RG-11/U runs from the delta loops to the tower for the stubs.

You have to look carefully at the dealer's specs to be sure. I bought my poly RG-11/U from the Cableman.  His stuff was FB and the best price out there.

T

That is what I thought, TNX. I avoid foam coax myself if possible. Today I plan to hang two new loops 136 feet long and 27 feet high. Also hang a quarter wave section of RG11 to the feed points at the bottom. Lots of simulation shows me this is a great match to 50 ohm source. So I willl drive one coax and hang a stub off the other.
The stubs at the end of a quarter wave section cost me a bit of FB but the antenna covers the whole band.
Jack I could also force feed it but all my simulation shows a weird Z so I need to look at some more simulations to see if it is worth doung. Guys running 4 squares make it play so still have not given up yet. At least both feed lines will be close to the ground so I can try different things.
My elements are about 5 feet shorter than the HUZ design with flat side down but I think my Z is back to around 100 ohms with the loops shorter height.  My present driven element is pretty close to 135 feet.

Yes the foam stuff is good for VHF, but not really much advantage at HF.  I'm using the regular poly stuff, although the lines out to the tower (over 200' )are hardline which has foam dielectric.

73,  Jack, W9GT

Well, I spent the morning doing a bit more simulation and found my stub hanging off the loops is very close to the HUZ design. So spent the afternoon doing 2 loops with #12 wire with stubs hanging down. The only difference was I ended up with a shorted stub on the reflector coax and feed directly to the driven loop coax.
Hope to continue Sunday and maybe JS something by evening.

I use the RG-11 from ComScope. IIRC the VF is about 0.8. Ontario Surplus was selling 100 foot length for cheap at the Timonium fest this past spring, so I got some.

Steve,
Your write up is confusing you say you have 18.8 and 13.86 foot hunks of RG 11 but that would be longer then 1/4 wavelength electrical since 32.64 is a quarter wave at 7.16 MHz. I ended up with the first hunk at 18.6 feet of RG11 at .66 VF. Should I read your lengths as 18.82 X VF and 13.86 X VF? This would explain why I come up with a shorter total measured coax length.

Those lengths were chosen for two reasons. The first length provides the proper inductive reactance for the reflector element when shorted. The second length was to added to the first length when connected to the driven element to produce a 50 Ohm impedance at the end. I didn't worry about whether it was a quarter-wave or not. The match was the important part.

But don't get too wrapped around the axle on those numbers anyway. They were based on models. I did not even need the extra matching section when I built the loops. The impedance was close enough to 50 Ohms. Adding any more 75 Ohm coax to the mix would have only made the impedance lower than 50 Ohm. Since your installation is different, you will need to find the correct lengths for your site.

Steve,
Just got it working again. I have 2- 20 foot lengths of RG11 hanging off the loops. I had to extend the driven element and now both are about 135 feet. I have a 9 foot stub hanging off the reflector hunk of RG11. Hope to add the transfer relay next and dial in the stub. I'm flat at 7.1 so close. Seems to play worked and listened to a few stations. proof will be when I flip it.
My VSWR came up the other day when I made the driven element shorter which was a mistake. So I agree you may not need the RG 11 at 20 foot spacing.
The 20 foot feed lines make it possible to work on the the switching close to the ground.

Steve,
I went back and looked at the simulation and find when you reduce the size of the reflector to the same size as the driven the input z of the driven goes up and wants the 70 ohm section. This makes me want to revisit the 3 element after I get this thing working. I'm not surprised that you didn't need the second section of RG 11 in series, since I got a good match with 18.6 feet of RG 11. I just need to dial in the reflector shunt since my simulation showerd it needed another 8 feet and you got away with just shorting the 18.8 foot line.

JS transfer relay set up at the tower and it looks pretty good. I'll dial in the stub when the band gets a bit longer. Loops are about 5 feet shorter than HUZ design and need to switch in a 8 or 9 foot stub on the reflector. RG-11 ohm sections are about 20 feet long. Covers the band at 2:1 VSWR. West a tad wider.

Here is one to think about. I get on tonight and get a few good reports with a little help from HUZ. But there is just one issue. The switching is backwards. I carefully rang out the transfer relay so power off points East but I have to power the relay to get a stronger signal to EU. So either I was brain dead this morning or I have a driven element director. Looking at the stub side I have 20 feet of RG11 with about 9 feet of RG8 as a shorted stub. This adds up to less than a half wave electrical which may be tuning in in the wrong direction. Last night  before I installed the relay I couldn't raise anyone in EU running 100W
But do I mess with 3 s units FB. Or take this as a stepping stone to 3 elements.
More simulation dumbo maybe the stub needs to be over 1/2 wave to be a reflector. It has me dreaming of a driven center element and 2 stubs flipped +/- 1/2 wave..  One othe clue when I shorted the 20 foot RG11 the VSWR was way off. It wanted at least 4 feet of additional coax to play.

Did you get the direction thing straightened out Frank? You got one report tonight of a 3 s-unit difference when you switched. That's pretty good!

Jack and Tom stopped by later. You should have come back after dinner.

We had a great time again tonight. 

Yep, we all worked a new one on 40M -  Billy, YC6NE in Indonesia.  I didn't think it was possible this early in the year. He was about a 5X6, not real loud but not PW. Billy is a big DXer as shown by his webpage.  That's a rare one.  (As I bury it in my notebook and forget about it by tomorrow... ;D)

T

I must have missed you guys. I got back to the shack about 8:15. Sounds like you had a good time. No I didn't climb up the tower and check the relay.
It was dark and I didn't feel like going out.

Yes, the band was better earlier in the evening. I listened later on and most of the signals were down about 10-15 dB. Same for 80 meters. Still worked a mobile in the UK though.  :D

Well I had a bit of light when I got home and checked the transfer relay. Yup it is a director. Element lengths are quite close to 140 feet and flipping  the pattern shifts the CF by about 20 KHz. the RG11 stubs are close to 20.5 feet and the switched stub adds about 9 more feet so just over a quarter wave electrical. Maybe the slightly longer stub then Steve has if flipping the thing when I go past 90 degrees. I need to dump some numbers in my 3 element simulation and let it loose and see what it wants. I have the center element fed so the reflector and director can have stub lengths as variables.
Tom remember old W1JF. Dick always thought that if spacing was under a quarter wave use a director rather than reflector. It works so not sure I want to change it just yet. I'm thinking I'll need to add more coax to the stub to make it a reflector....or make it a lot shorter. I like working from the ground, getting too cold to climb. 

You'll want a reflector.

I want to figure out what is going on. I may have to add another 45 degrees of length to flip it back to a reflector. I don't want to cut the RG11 much shorter but hope to find some quality N connectors Friday. If that is a director and I can make it a reflector than it will be 3 elements shortly after that. You are about 11 feet shorter than me for the reflector stub which is darn close to 45 degrees. Our loops are within a foot of each other total length. My loops not quite as tall about 30 feet and you are around 40 feet so I would think I have a slightly higher input z, but I'm closer to the ground so that may pull it back down.

Steve your 18 feet is a good number even in simulation. I'm playing with a 3 element that wants 32 X VF for director and 22 X VF for reflector. I started at about 20.5 feet so adding more length flipped it. I have a 3 element simulated so it will take 50 ohm feed with a 1.3:1 VSWR on a 20 foot boom.

I've been on the receiving end of Tom's 2x2x2 and can hear nothing else coming out of the States even close, it's head and shoulders above the rest. ;)

Nice to work you the other night on 40M, Gerry!

You were ceratinly the Euro-ChannelMaster in here from the Land of Ire.  It's always good to see our big efforts pay off.  Thanks for the report, OM. Hope to get on sometime this weekend on 40M.  Be sure to give me a call if you tune in.


73,

Tom, K1JJ

A picture of Gerry's multi-band quad:

Tom,

Your story about the low 40 array opening the band into Europe is fortunately a common one.  Once, in a galaxy far, far away I was the 40 meter op at W2PV in Schnectady NY and I do so vividly remember the low (60') forty meter yagi grossly outperforming the stacks on forty until the sun was set.  The low 40 outdid a stack at 60 and 120 on one rotating pole and the single low 40 made a fool of the stack at 220' and 110'.  All of Jim's 40 meter antennas were Telrex three element beams on very strong booms.

Jim, W2PV, explained to me the wave theory that caused the low antenna doing so well and it all had to do with the high angle antenna (the low one) getting through a specific layer quickly, while the low angle signal dawdled in this region and lost its amplitude on it's way through.  It all made sense!

Get the driven elements set up correctly and you will have a ball with the big array.  Just be sure you can switch your lowest 40 meter yagi so it's all by itself until well after sunset.

73

Natan W6XR
Freeville, NY 

Interesting info, Nathan.

Good going -  you associated with the master, W2PV. Many still refer to his famous writings on Yagis.

Since posting the results using a lower reference Yagi against the stack, I now use a simple isolated dipole at 45' as a reference against the stack.  I  see at least  12db in favor of the stack until an hour before sunset. Then as time gets closer, the stack really starts to perform and can be as loud as 20db (or more) better than the dipole an hour before and after sunset.   I'm sure a lot depands on the time of year and band condix, of course.

Last week I wanted to see how early in the day I could generate a pileup into Europe on 7133 khz. At 12:30 local (afternoon) the sun was high and I could easily hear Euros talking, however most were beaming VK and east. I got on and called a few. Some thought I was a Euro playing games and others had their antennas facing the other direction. It was not the norm for USA, I found. I then called CQ and slowly drew in a good pileup. I found I could barely hear them on the dipole and contacts would have been few. But on the 2x2x2 stack it was cake and quite a thrill. The best part was hearing Euros say they never worked USA that early in the day on 40M.  Next I want to try it at 9AM local when it's still full daylight in Europe to see what happens.. :D.  I think the lowest angle possible will be best then, but will have to find out.

The take off angle is down around 13 degrees, a single focused lobe on the horizon - so it is always interesting to see what a lobe that low will do with the ionosphere.

I hope to put in a homebrew in-phase / out of phase switcher next  summer to try some higher angles. As the sunspots come back, I will wish for higher angle lobes, I am told.

73,

T