Advice from Tom K1JJ and Steve WB3HUZ seems to be paying off

[K5UJ]

I've been pretty much QRT for over a month now, because I took down all my antennas (or in one case, tore it down by accident  sooner than I had planned but the scrap aluminum came in handy)  and started work rebuilding the K5UJ antenna farm. 

Down came most of the 4 MHz low hanging horizontal loop, inverted L for 160 and the premature dismantling of the Gap Titan vertical, which by this time was not doing much more than holding up part of the inverted L, and occasionally finding use as a noise pickup antenna for my phase canceling box.   Then the work began.  Good antennas are a lot of work--even dipoles.  There's a reason why those snake oil antennas sell--they're easy.

First up was a 50 foot 3 inch o.d. aluminum mast topped by a 15 foot stinger.  It's on a hinge so it can fold over and is guyed at 31 feet.  It holds up the 160 m. inverted L wire, a 33' wire for 40 m., and since it's insulated on a pressure treated 6 x 6 pine post, can be fed itself as a 1/4 w. vertical on 75.  It also holds up one end of the 80 and 40 m. center fed dipole.  I got as much mileage as possible off that mast.   I could not have done this alone.  At key points when I was overwhelmed or not physically strong enough two local hams stepped in with strength and mechanical know-how:  Jeff KB9YSJ and Charlie KC9DAO, the owner of Penninger Radio from whom I purchased the aluminum mast and hardware.  With Jeff's help I also put up two steel 40 and 44 foot  push up masts on a higher elevation of my property.  I had purchased these in 2005 and was only now getting around to using them.  Extending them was a royal PITA because the lubricant had long ago dried up and the sections and guy rings seized up and did not want to move.  These things are dangerous.  When they do move, they really fly and if you are not wearing thick gloves your palm will get grabbed between an inner and outer section and hamburgered up. I know  but the scabs are almost gone but boy did it ever hurt!  I covered them in axle grease and got them moving but of course you can't push them up if they're greasy so the grease had to be mostly removed.  even so, pushing up the last section with two or three above it was very hard for me.   I took a week off work to do all this first week of August.

Last weekend and yesterday, the dipoles and inverted L went up.  The 80 and 40 dipole is 130 feet long with the center held by one of the steel masts and the other end held up my my one and only tree.  The ends dangle down about 20 - 25 feet.  Then the small 10 - 20 m. dipole at a right angle to the big one.   This is 26 feet long and suspended between the feedpoint steel mast and the third steel mast which also holds up part of the Inverted L wire.  The layout looks like this:

L


_______
|         |         x <(holds inverted L wire and north end of small dipole)
x         |
           |
           


T

With L being the Aluminum mast, x the two guyed push up masts and T being the tree.  The lines indicate the path the feedlines take once they are at ground level on their path to the basement shack entrance.   The feedline on the ground is held up by pvc pipes and T sections.

The big dipole is up somewhere between 40 and 50 feet, probably 45 feet average.  The small dipole is 40 to 45 feet high.
Both are fed with 600 ohm ladder line and tuned with a pair of roller inductors and a vac. variable cap. 

While these are relatively simple wire antennas, the size of the lot (50 x 100 feet) and the lack of trees except one, made this project a pretty big challenge for me.  By the time I was trying to push up the greasy masts (thank goodness for paper towels) in 90 degree heat and humidity I was really wishing I had done this one antenna at a time instead of everything at once.  I don't plan on doing any more big antenna changes anytime soon    and told a few friends to slap me if I get any ideas.

Yesterday I checked into the K9ACT Noon-Time Forum on 3870 running the dipole.  It didn't take long to see the benefit of getting a wire higher up thereby reducing ground loss.  Running around 300 watts at noon some guys reported my signal at 30 to 35 dB over S9.  Last night a friend in Indianapolis told me I peaked at one point at 20 over S9 with a 75 watt LSB signal (he has a calibrated S meter).  I'd say these are roughly 10 to 15 dB over what I had before, but of course it takes time and an averaging of conditions and QSOs to know anything for sure.  But so far, I'm very pleased.

The small dipole hasn't gotten any RF yet but I listened around with it on 20 and it seemed to be hearing quite well.  Ditto for the 40 m. vertical.  All the verticals share the same ground system, 101 radials of varying lengths, 10 to 120 feet long, no. 14 solid wire.  Not surprisingly, there seems to be some interaction between the inverted L and the 130 foot dipole.  I see it in tuning the dipole when the inverted L is up in the air.  I'm going to have to play around with that and see if there's anything I can do to "detune" the L -- let it float perhaps.  As a last resort I can drop it to run the dipole (all the antennas are on marine  pulleys so they can all be hoisted and dropped when needed) because it is probably unbalancing the dipole.  I'll have to look at the RF currents in the feedline to the dipole to get an idea of what's going on..

A high center ladder line fed dipole seems to be a great AM antenna hi hi.

73

Rob K5UJ

[Steve - WB3HUZ]

You should always listen to me.     Actually, listen to JJ, he's the antenna guru, he can levitate and he eats Sushi.

All kidding aside, glad to see things are working out well. Congratulations on taking the bull by the horns and getting it done. In my experience, all the hard work on antennas is worth it when you get good signal reports and can hear stuff you couldn't hear before.

Enjoy your new lease on RF life. Hope to hear you on the air soon.

[flintstone mop]

Rob,
You will have to quit hooking the guy wires to the bumper of your car. 

Fred

[K5UJ]

thanks guys, maybe I can get to 3 land on the vertical or the 20 m. dipole.  Yeah Fred, the Gap was no loss but now, I have to be careful!   Don't want to accidently pull down the steel mast!  I forgot to mention that the L wire bends around and over the house to get it to fit on the property.  The verticals are all fed with LDF450.  The northerly mast is bracketed to the front of the Antenna Maint. Shed which began life as a garage but a car has not been in there in years.  Now it is home to things like R20 tower sections, tools and mast sections, and other hardware.  Speaking of hardware, I probably went through 1200 feet of dacron.  Antenna hardware is expensive now!  One galv. steel earth screw is $20 - $30!  I'm out well over $1000 for this project which isn't much if we're talking about a tower, but wire antennas....jeez.

Rob

[K5UJ]

Going to try to upload some photos of the antennas since I rx a request ...

[K5UJ]

Here's some more....

[K5UJ]

and a few more

[Steve - WB3HUZ]

Very nice. Where did you get those steel masts?

[K1JJ]

Looks like a well thought out installation, Bob!

Yes, simple dipoles that are straight, flat and well matched (open wire and tuner) are hard to beat. In fact what you've put together there should receive an award for the best utilized "small" lot of the year...


I'll be very curious how that 26' dipole, openwire center fed for 10-20M works out. It models very well and we've been talking it up for years now as a good candidate for the higher bands.  At well over 1/2 wavelengh high on 20M and higher on 10-15M shud work like a bomb for both stateside and Eu.

I'm glad to see you took down that large loop that was hogging the precious antenna field and have now  "surgically" erected optimized antennas. You will smile every time you use those systems.  It's heartening to see someone take the advice of this forum, think it over and put it to good use like you have.

Yes, the fine tuning aspect now is to see what is interacting  with each other and it looks like you've already made some good progress and solutions there.

Your estimate of 10-15db improvement over the old antennas is what I would have expected. Again, it's amazing how well a straight, high, flat, simple dipole works.

Keep posting your on-air results  - especially on the higher bands.

Good luck, OM -

Tom, K1JJ

[K1JJ]

Bob,

BTW, to accurately test your inverted L for interaction with the 75M dipole....  put a termination (dummy load) at the end of the feedline coax for the "L" with a wattmeter (or swr meter) in line. Put the wattmeter on the most sensitive reading.  Then dump 100 watts into your 75M dipole.  If you are seeing 1 watt or less coupling into the "L", then that's OK. This is about 20db of isolation. If more, then you need to detune the dipole when the "L" is being used  - or detune the "L" when the dipole is being used.  Otherwise they are ONE antenna and will give you a pattern that is not what you designed. Control of your pattern by isolation of antennas is important, especially after the great effort you've been through to accomplish this already.


The same tests shud be perfromed on the other antennas too, especially the verticals, to see if they are coupling RF into the dipole feedline vertical runs. Ya never know until you test every combination of antennas for interaction.

I won't get into more details until you make that measurement first.

T

[K5UJ]

Okay Tom Thanks very much for the encouragement and everyone's kind comments-- I'll try the small dipole the first chance I get--I've tried tuning it with the balanced transmatch and it seems to tune okay.  I operate 20 m. so infrequently that I'll have to take a look at a bandplan first    also great idea about putting a wattmeter and dummy load out there I'll bet I see more than a watt on it.  I have everything to do that with sitting around so it should be an easy measurement.  Wx has been a problem this p.m. though.

Yes, nothing beats having at acre or more under ur control.   Tree in the way?  No problem, down it comes.  But on a small city lot these things are usually someone else's and you have to work around them and keep any guying anchors on your property.  This limits heights and so on.  If I want to do any more than what I've done I'll probably have to move.

Steve, the steel masts came from Majestic Communications in Memphis.  I bought them in 2005 when I was down there taking care of my mom when she had a case of flu.  After she got better I found that they had them on the internet.  They had two left that they wanted to get rid of so they sold them to me for $90 ea. a $30 discount.  They were made by Tesso in Canada as I recall.  From my experience with them I'd say steel push up masts are okay up to 30 feet but above that you're better off with a tilt-over aluminum mast or light-weight Al lattice tower for holding up wires. 

I have some ceramic feedline spacers and I toyed with the idea of making my own ladder line but I'm glad I didn't.  There's enough weight up there already with the ceramic dogbones, and no. 12 wire.  Reducing the sag puts a surprising amount of tension on the ropes and structures--I should have known that by now.

Well we had our first baptism by fire when a big storm blew through here this evening; everything seemed to make it.

The real tests come in November and toward the end of winter.  Those are the two times of the year when we get deep low pressure centers that drift through the upper midwest usually across Wisconsin.  They take about 24 to 36 hours to move in and out and during that time we get very narrow pressure gradients which result in sustained winds of 30-40 mph gusting to 50 or 60 mph.  It's one thing to make it through a 15 minute storm but there are not a few summer antennas that come down during one of those 24 hour battering sessions because they went up on a nice still day and the owner wasn't thinking about the gales of November.

[w4bfs]

.... because they went up on a nice still day and the owner wasn't thinking about the gales of November.

with apologies to Gordon Lightfoot, I hope there is no other similiarity in your antenna system to the Edmund Fitzgerald

nice work ...I must do the same soon ...73 ...John

[K1JJ]

FB on all, Bob.

Yep, that 10M-20M  26' long dipole is by far the best performing antenna you have up, relatively speaking.  It even covers two of the WARC bands.  It will give you lots of smiles.


I once had a pair of 50' steel telescoping masts. They worked really well and were very strong when guyed every 10'. I could put a ladder against it, no problem.  I once used them to support a 36 element wire curtain array for 20M using bridles at the top. The mast bases were 20' long pieces of 2"X12" studs in concrete that tilted over - about 70' total height.  It never went through an ice strom and I doubt it wuda survived anyway.



BTW, you can also use your scope to measure power accurately with the probe across the dummy load.   P = E squared / R.    If I remember  correctly, use p-p voltage / 50 ohms. (Someone please correct me if it's not p-p voltage on the scope and something else.


This power wheel chart is a good formula reminder for other combinations of P, I, E and R:
http://www.sengpielaudio.com/calculator-ohm.htm
T

[K5UJ]

.... because they went up on a nice still day and the owner wasn't thinking about the gales of November.

with apologies to Gordon Lightfoot, I hope there is no other similiarity in your antenna system to the Edmund Fitzgerald

nice work ...I must do the same soon ...73 ...John

thanks john, I hope so too hi hi.  I'll be keeping an eye on the aluminum mast; the steel ones should be okay.

[K5UJ]

FB on all, Bob.

Yep, that 10M-20M  26' long dipole is by far the best performing antenna you have up, relatively speaking.  It even covers two of the WARC bands.  It will give you lots of smiles.

I once had a pair of 50' steel telescoping masts. They worked really well and were very strong when guyed every 10'. I could put a ladder against it, no problem.  I once used them to support a 36 element wire curtain array for 20M using bridles at the top. The mast base were 20' long pieces of 2"X12" studs in concrete that tilted over - about 70' total height.  It never went through an ice strom and I doubt it wuda survived anyway.

BTW, you can also use your scope to measure power accurately with the probe across the dummy load.   P = E squared / R.    If I remember  correctly, use p-p voltage / 50 ohms. (Someone please correct me if it's not p-p voltage on the scope and something else.

This power wheel chart is a good formula reminder for other combinations of P, I, E and R:
http://www.sengpielaudio.com/calculator-ohm.htm
T

Thanks Tom; if we get a threatening amount of ice I can drop all the wires to the ground, one reason for the pulleys.  Every ham dreams of having a dipole curtain; you are one of the few who did it.   wow.  I think you should have gotten around 20 dB gain over a dipole with 36 of them maybe a bit more.  okay on the scope and chart too.  will let you know what I find.

Rob

[flintstone mop]

Hey Rob
You bring back great memories of being able to plunk down some dineros and get major projects up and running. Congrats. Good design for the tilt-over, but looks like a 2 man operation.

I hope I can glom onto a 50 military mast that can be deployed by one person. (you have to keep your wits about you, though) It's an AB-77?? They're around a grand now. Price was $400 in 2000. My former employer might "give me" their 50 footer.
I hope we can connect via radio soon

Fred

[Steve - WB3HUZ]

I talked to Jack,W9GT on 40 meters last night. He was 40-over-9 at times. I'm sure I would be able to hear you on 40 meters.

[K5UJ]

FB re 40 m. Steve I will check 7160 when I can evenings; hey fred that's great re the mast hpe that works out -- yes, the 50 foot aluminum mast was cranked up the first (and so far the only) time by me and a friend because we didn't know what was gg to happen so I was under it with a ladder for it to be lowered on to if it looked like it wasn't gg to make it.   However, it cranked up so fast by the time I was under it and holding the ladder, Jeff said it's going up, and a few seconds later bingo there it was.  The first time you put up something that's higher than anything you ever put up before, it looks like the Sears Tower, then after a week or two it settles down to size.

I got back into town this afternoon and did a little experimenting with the dipole.  First, I put a 20 w. watt meter on the inverted L between it and a dummy load and put 75 w. on the dipole on 3880.  Nothing on the watt meter.  so far so good.   I noticed that the vswr on the 80/40 dipole with one of those mfj analyzers with the matching network tuned to 50 j3 is 1.0 : 1, but when I tx 20 w. and look at the forward/reflected power on a meter at the input to the matching network, I'm seeing around 2:1 vswr.  Tune the transmatch to zero power reflected and go back to the swr analyzer and the vswr on it is around 1.6 : 1.  Well obviously, the antennas not in use are passively reradiating power back into the swr analyzer and screwing it up, but there isn't enough pickup on the inverted L when the dipole is getting 75 w. to register on the watt meter.  so I go outside and drop the 160 m. inverted L to the ground.  Problem still there.  so, that's where I am now; the investigation continues.   Could be the masts, or high band dipole.  Doesn't really bother me in that the low band dipole seems to work well anyway, so it's just a fun thing to experiment with.

On the way back from Omaha today I stopped off in Mitchelville Iowa and looked at the WHO 1040 tower.  Very interesting and one surprise is that it appeared to be a sectionalized tower.  I'll have to look into that and see what they're doing with it.  They have an old batwing tv antenna on top of it which I imagine is no longer in use.

In Omaha, I took time to hunt down Surplus Sales.  Very disappointed to report that Surplus Sales in-person customer service is very unsatisfactory which is a nice way of saying I was politely told to get lost.  They're in a huge brick warehouse building in an industrial section of Omaha (they even put a photo of it on their website) but when I got there yesterday, I found a windowless locked steel door with a sqwauk box and call button next to it.  A faceless voice told me they only sell over the internet and do not allow walk in business and that there was nothing to see here.  Well, if the website is anything to go by, I think there was probably a lot to see.  They used to have a showroom but got rid of it.  I suppose in-person encounters were too much trouble--all those pesky customers demanding service.  You'd think they would put some message on their website telling people to stay away and only order from afar.  Well, after that I decided to take my business elsewhere whenever possible. 

Rob

[K1JJ]

Rob said:

" First, I put a 20 w. watt meter on the inverted L between it and a dummy load and put 75 w. on the dipole on 3880.  Nothing on the watt meter.  so far so good.   I noticed that the vswr on the 80/40 dipole with one of those mfj analyzers with the matching network tuned to 50 j3 is 1.0 : 1, but when I tx 20 w. and look at the forward/reflected power on a meter at the input to the matching network, I'm seeing around 2:1 vswr.  Tune the transmatch to zero power reflected and go back to the swr analyzer and the vswr on it is around 1.6 : 1. "





Rob,

Is the MFJ-259 analyzer in the same exact spot (in the coax line) as the wattmeter when the tests are made?  If not, then the impedance will be different if the match at the antenna tuner input is not a true 1:1 50 ohms, regardless of what the MFJ says right now.   This also assumes the wattmeter and MFJ are both 50 ohm devices.


Sometimes my MFJ acts funky and gives strange readings. I'll have to think more about it.

Otherwise, I wouldn't worry about it. Just tune up your transmitter's pi-network properly while adjusting the antenna tuner for min swr at the tuner input and you will be FB.


Good to hear the antenna interactions are minimal. That's great news.


T

[K5UJ]

Hi Tom thanks-the transmatch swr (forward reflected watt) meter (It's one of those Daiwa cross needle jobs, not great but could be worse) is at the end of a 3 foot RG213 HB bead balun pigtail coming out of the tuner.  The analyzer is at the end of another 3 foot 213 jumper coming out of the Daiwa.  so not exactly the same place but on 75 meters pretty close.

Rob

[K5UJ]

Well about an hour ago W0HRO in St. Louis told me I was 40 dB over 9 (I'll take 10 or 20 hi hi) on his sx28 on 3885.  I was running a 30 w. carrier.

[W1VD]

You're currently 59+10-20 in CT on 3885. Looks like it's working...

[K5UJ]

You're currently 59+10-20 in CT on 3885. Looks like it's working...

WoW TNX the Check IS IN The MAIL!!!    (I think 75 was in really good shape tonight too)

Rob

[K5UJ]

Another pleasant surprise is that the noise level seems to be about 2 S units lower on the higher dipole than it was on the loop.  And even better, I'm not hearing any appliance noise (knock on wood).   I guess the dipole is more isolated and/or the loop passed nearer the house that was putting out the noise.

Rob K5UJ