The AM Forum

Now that 10 meters is coming around, if you don't already have something up  for that band, take a look at two articles on The AM Window. The first gives details on how to build the antenna, a nice 2-element Yagi.  The second is more general and covers several different types of antennas. The info in this article can be scaled to other bands.

Two Element Yagi For 10 Meters by Tom - K1JJ

http://www.amwindow.org/tech/htm/10m2el.htm


Simple Antennas for Ten Meters by K4HX

http://www.amwindow.org/tech/htm/tenmant/tenmant.htm

44 foot lazy H is a great antenna 40 through 10 meters if you are using wire

Steve i sright. The 2 element works great. I've built the 10 meter beam just as Tom descibes it. I also scaled it up for 15 meters and it works HI HI FB OM!

for me it's my 20 m. halfwave dipole center fed with ladder line and matchbox up 35 feet (the dipole is up there not the matchbox hi hi).  broadside to southwest and northeast.  probably get four leaf pattern on 10.  have not been on 10 in a few years.  lotsa fun when it is open and 30 watts is plenty.

I use an old shortened Maco V-Quad (delta loop) beam.  It's light, easy to mount and turn, works good at low height.  Mounted for horz. polarization it outperforms my wide spaced 3 el yagi when the band is marginal. 
Darrell KF4DX

I am planning to build two Bi-Squares for 10m and hang them off the side of the tower at 50 feet.I am also constructing a 2-element Delta Quad for 20m.

Good stuff. Always interesting to see what others are running or planning. Keep 'em coming!



What's the going price on these used?

Gee, I have a spider quad center mount. Maybe I'll bring it to Deerfield.

Some of the CB 1/2 wave and 5/8 wave verticals are fun to play with on 10 meters. I guess you can pick some up on epay for $50-$100.
The old Antenna Specialists M400 Starduster was real popular in Northern Ohio in the mid to late 70s for 10 meter ops.
I used an old Avanti Astro Plane and worked DX on a regular bases back then. I saw one on Craig's List for $40.

Some good ideas. I'd be curious how those pair of bi-squares work out on 10M.


The old 2el stacked 10M Yagis have morphed into this homebrew stack at 33', 66' and 99' :  (On swing gates that cover 300 degrees)


T  

 "  The old 2el stacked 10M Yagis have morphed into this homebrew stack at 33', 66' and 99' :  (On swing gates that cover 300 degrees)  "



T,

I hate you.

klc

tom needs to setup a rig that you can remote operate and charge 10 cents a minute or what ever hahaha. try a station at your qth a few times, if ya cant get him, log into the remote k1jj maul .com  site and talk all the dx you want.

OK, OK... if you guys MUST know, here's the secret to ham radio humility:

Tom I got to see a Gotham Vertical + B&W loading coil in person on Nantucket  in 1958 hooked to a DX-100.  It was stuck right in the Salt water and he could work the cape ground wave  5x5  to 5x8. Not many had a trailer 3 feet from high tide !

 What are your favorite swing gates ? John, K1DEU

John,

Yes, the Gotham vertical... as the old story goes, the Gotham was my first antenna as a new Novice. I called CQ for three days without an answer...  :D

The swing gates you see are homebrewed from scrap yard steel using an arc welder. I've made them for most of my Yagis.   But there is a vendor from Ohio, I think, who has ads out there somewhere. They look pretty strong, though are not reinforced as much as I did mine.

Here's some close ups of 20M Yagi gates if you wish to duplicate one. Notice the method I use to hang them on the tower using 2" steel pipe stubs welded to brackets. The gates sit on the bottom stub and the top stub holds it in place. Grease inside both housings and swings smoothly. Notice how the Yagi boom's overhead trussing anchors to the center swing gate mast. 

These Yagis will turn 300 degrees around the tower. I use a strong rope for each anchored to the ground. I hate rotators and wud go for a rotating tower first ;)

BTW, those 20M Yagis each weigh about 300 pounds each. Axe Gary, Steve and Johnny (and me) after we lugged them to the tower for staging.


** That new 190' tower of yours is just begging for a stack of 10-20M log periodics with a 40M Yagi to boot.... ;D

T

I have used several antennas on 10M. It is hard to beat the old fashioned ground plane for a simple low angle radiator. My last one was off the kids swing set! It was simply a steel conduit and 5 radials. 

My last 10M antenna was a rectangular full wave loop hung vertical and fed at the bottom for a good 50 Ohm match and a horizontal polarization.
http://kt4qw.com/acan1bu.htm

Another good antenna is the 5/8 ground plane with a coil match with several horizontal radials at the 10 ft level.

Finally an 80 degree Vee beam with 120 ft wires works good on 10M with a quarter wave matching stub and a 4:1 balun. If you use an open half wave stub, you can short the end and use the antenna on 20M too as a shorted stub. I was able to find a feedpoint that allowed a great match on both bands simply by opening and closing a small knife switch hanging off the end of the 17 ft stub just within reach.

When I was 15 or 16 on vacation at Giants Neck I met a guy who was staying down the street. He had a TR3 or TR4 connected to a gotham. We worked a pile of DX that week with it plugged into the ground just outside the house.

Tom, are those 10M a standard design or did you do it on the PC?.

Im thru with the 4 high stacks of 4 el and want to go with just one single yagi with under a 30' boom.

Worked the VU4 on 10 the other day with half a reflector and 2nd director.

To use the lazy-H on more that one band, you can't use the feedline scheme shown in the Amwindow article.    Use distributed feed that is not frequency dependent and make the elements for the lowest frequency band.    Check out this website for more info:

http://www.w8ji.com/curtain sterba USIA array.htm

This may work better, can't seem to copy the website address right:

http://www.w8ji.com/curtain%20sterba%20USIA%20array.htm

Hi Carl,

All the Yagis here were designed using Yagi Optimizer (electrical) and Yagi Stress (mechanical) software. Notice the 20M Yagi elements sit on fiberglass boom to ele mountings to keep boom currents out of the equation.

I kinda agree about the single Yagis at times. The most fun I ever had on 10M was with a simple 2el Yagi, stacked three, fixed on USA for 10M AM. Very broad horizontal and simple design.

I rmember Arnold always ran single Yagis and commented that stacks are a waste. Really, all they do is fatten the lowest lobe by eliminating the higher lobes, producing less fading at the lowest DX  angle. The added gain is not much.

When the stack works, it realy works. The difference to the reference dipole is enormous. But when angles get higher, the stack has holes.

The older we get, the simpler we like out antennas for maintenance - and single yagis are a good compromise.

T

With a voice like one ;D

Tom, I have YO here also. Is it in the library or would you send me the file?

The good thing about stacks is that each antenna has a null angle somewhere and when you can switch enough combinations you fill in those holes. They are great for contests where you have to be able to hold a run frequency or follow the propagation to the next skip zone or be able to bust a pileup real quick.

Maintenance here was always a PITA with the 4el top KLM 40 but the other bands survived for over 20 years....all HB....which is more than I can say for many of the credit card contesters in the area...... and I didnt waste time on Leesons book

I ran a 2 element quad for 19 years. It really worked well on 10 meters. I had a feedline for each band.
WARC pushed me to a LPDA.

Was at a local ham store today, and just happened to pick up the latest copy of QST that was laying on the counter.  What got my attention (since I'm not a member of -any- "organization" related to operating ham radio) was an article about 'Nesting Delta Loops'.  My immediate thought was 'why?' 

Basically, if you've got room for a full length inverted Vee on 75m, you've got room for a Delta Loop.  Feed it with open-wire-line and an impedance matching device, and you've got -one- antenna that works all bands the impedance matching device can handle, 75m and up in frequency.

I know of a guy (Jon/AD5HR) who lashed up a hair-pin tuner to match 144.200 SSB to a 75m square loop.  First crack outta the box, worked an XE2 somewhere south of the Arizona/New Mexico border.  Pretty respectable distance from South Central Texas!

Yet another reason I don't read QST.

The title of the article is: "Nested Full Wave Delta Loops for 20 and 10 Meters". Nothing to do with 75 meters. Further, within the first paragraph, the author indicates that his present location is situated on a very narrow lot so he probably doesn't have room for much.

I've never had any luck with a 75 meter loop close to the ground, simulation agrees. I bet an inverted Vee works better.

Point being, Pete, if he has room for a 20m full wave loop, why waste the wire for a 10m full wave loop inside the 20m loop, when he can feed the 20m loop with open wire line and use it on 17, 15, 12 AND 10m as well?

all I did to make my delta loop is close up the bottom of a 75m inverted vee.  Kept the feed point at the apex, changed from coax to open wire line and the changes were phenomenal!

Now that you have open wire  feed, try going back to an inverted vee????
This will increase the average height of the antenna. A loop may work better if the ends of the inverted vee are too close to each other.
I tried and failed to make a 75m loop work close to the ground.
Then I learned to use antenna simulations so I didn't waste my time.
The bottom of a loop really wants to be a quarter wave above ground or you make an inefficient cloud burner.
As you go higher in frequency interesting things can happen.

Tom quite the Gates   Rotation time is never boring

Swinging Gate Side mounts  There are several pre-made One from Max Gain I.E.  IDC  not available until July  nearly $500
    
 http://www.mgs4u.com/IDC-Technology-sidewinder.htm


Custom Metalworks  $230 for Rohn 45g

http://www.arraysolutions.com/Products/cmwantsidemount.htm

With detailed pictures   http://www.arraysolutions.com/Products/sidemountusersguide1.htm

Yea love to have a pair of Log Perodics

I get pretty good reports from the East and West coast.  Bottom of the loop is probably 20'.  Apex is closer to 60+feet.

Interesting pics / links on the commercial gates, John.

I would say that if you "Armstrong" rotate, the less expensive Array Solutions units look good. Otherwise for rotators, the $500 MaxGain looks FB.

BTW, the log periodic is your best bet. I know you mentioned getting one of those complex, interlaced, Force 12 multiband beams, but think twice. The log periodic is the best choice for many reasons.  If you could possibly stack two, you will have it all, OM.  The 24' boom Tennedyne, once reinforced, is FB. Axe Chuck about having the manufacturer modify it for a little more $. Well worth it.

T

Don't know. Maybe he doesn't like the unsightly look of open wire line dangling down; didn't read the entire article. Many amateurs prefer the use of coax feeds over open wire line feeds. In 50 years of hamming, I've never had the urge to use open wire line feeds.

 

Many, myself included, have no use for open wire line, or any balanced line plus the aggravation of an antenna tuner.

At one point at another QTH here in town I had 3 80M slopers off a 100' tower that were somewhat effective but not pileup or contest competitive. They got replaced with a Delta Loop that I could switch polarization and it was better than the slopers for DX and stateside; took 2nd place a few times in single band CW. Then I installed a pair of full size cage verticals hanging from pine tree branches and with an extensive radial field. That was often the best as I could show lower angle gain in 2 cardiod patterns as well as a figure 8 broadside where the loop was in a null. It also was configured as a pair of 40M with 2 figure 8 patterns but it wasnt very effective.

With the 2 antennas for 80, a 4el KLM for 40, the 100' tower shunt fed on 160, and the existing 4el W2PV Christmas tree the station won the USA in the next ARRL CW DX contest. Not bad for a 40K Sq ft lot in the lowest part of town ;D

Carl

This topic was supposed to be about 10 meters antennas. If you wanna talk about other bands or other subjects, start another thread. Thanks.

I'll throw my two cents worth in here...  Don't know much about 24-30 mhz though...  :)

The absolute best antenna for 10 meter OMNI I've found, for quality of materials, customer service, support, etc. is http://www.a1antennas.com and the Interceptor 10K.  It AIN'T cheap, but you DO get what you pay for.  Mine failed (it's my 2nd one.  My 1st was stolen while I was relocating 3 states away.  Came back, 2 RF decks, a power supply, antenna and support where GONE), and I notified the mfg.  They designed a new lower section to handle the wind and ice loads I get.  It's NOT uncommon for me to have > 100 mile an hour gusts, 80+ sustained, and 2-3 inches of radial ice load.


The mfg also gives instructions on how to tune the matching network if you want to use it on another band.  It's a 5/8, and performs just like a 5/8 should. 

The matching network is VERY robust, and will handle at LEAST 25kw. 

Performance on both of them that I've owned is <<about>> on par with a 3 element gamma fed yagi from the CB mfg Maco (it's what I had to test it with, installed per instructions years ago)...  The I10K performed just about as well...  Even taking into account pattern skew from the gamma feed on the beam.

The I10k is DC grounded as well.  It uses marine grade stainless for all connections.  Hose clamps are above the quality I've found in most commercial antennas, and something you'd see out in the open ocean... Breeze Hi Torque ALL stainless.  Most 'stainless' hoseclamps at home depot still have a zinc drive screw, and that will rust up..  These don't.

There is another mfg that has an antenna that is very similar...  The build quality isn't the same.

For someone wanting higher power, you supply a connector of choice, they will ship it back that way.  I know of more than a couple running DINs and LCs.  I put an N on mine, due to the weather issues here.

No connection to the company, just a satisfied customer...  I did work with the owner years ago sharing info I had amassed about different GP antennas....  Jay, the owner, took all he could find and made the best antenna I've found.

Mine is currently in 60-70 mile an hour gusts.  The antenna is doing great thus far, and FULLY erect :)

--Shane
KD6VXI

I saw that article and wondered about using a 20M loop with open wire line also. So I did a tiny bit of research and also a little bit of antenna modeling and it turns out that a delta loop used at its full wave freq has a better pattern. Mostly lower angles, and according to what I read, lower noise pickup. In real life situations who know? The convenience of multiband use with the open wire line is very appealing.

You are correct Larry. When the loop is a full-wave, it produces a nice bidirectional pattern (and with a low take off angle, if it's at the right height). But once you move up to 2x and 3x the fundamental frequency, the pattern falls apart (more lobes and nulls and the take-off angle can be too high). Sure, you can feed the loop with with open-wire and tune it, but the performance will not equal a separate properly sized loop fed with coax.

A dipole is still hard to beat for a simple 10 meter antenna. Other than being omnidirectional, a quarter-wave vertical is not nearly as good as a dipole. Check the simulation results below. Even at the peak take-off angle of the vertical, the dipole beats it by 6 dB!

What he said!

It's hard to beat a simple 1/2 wave dipole at 1/4 to 1/2 wavelength high. The horizontal pattern is always a broad figure 8 and the take-off angle is directly controllable by height.  That's why they are so popular. Single band coax fed makes it EZ.

We marvel at a 3el Yagi, but a simple dipole at the same height is within 5db of a Yagi.

Yes, openwire-fed multiband antennas have their advantages with a single antenna covering all bands, but the disadvantage is we lose control of the broad figure-8 pattern on the higher bands which is so important to stable geographic coverage. Personally, from CT I like favoring NE and SW. That's where the population centers are. An antenna with opposite lobes facing NW/SE would be favoring Alaska or the south Atlantic Ocean - with nulls facing the USA and Eu. The difference can be 20db.  That's why I like simple 1/2 wave dipoles, if possible.

Another point: For horizontal antennas, since a wire antenna's take-off angle is based on its AVERAGE height, a simple 1/2 wave dipole is usually easier to get up to a higher average height than a lower hanging loop, extended Zepp, etc. An extreme case would be a tiny 10M dipole vs: a 75M Zepp used on 10M and all bands. Think about it.

The best way to tell if a new antenna is "working" is to have a reference coax fed 1/2 wave dipole mounted at least 1/2 wavelength away at the same AVERAGE height and orientation.  Most of the time we will be disappointed and realize it IS hard to beat a simple dipole.  If it's a new Yagi, then it better show a good 5db or more improvement. DB's are hard-earned.

T

You mentioned this system in years past - stacked dipoles. This system really is a winner. You still get the broad lobes of coverage, more gain, and a take-off angle as low or lower than any vertical. See below - 9 dB more gain!

Yep, and take it a step further...

For those who want to dedicate an antenna to one band, (like 10M) consider the popular pair of phased dipoles, but stacked. (Four dipoles, switchable NE or SW)   With one set at 20' high and the other at 40' high, there would be a marvelous uni-directional pattern. Bring two coax feeds into the shack, one from each pair of phased dipoles and add ~120 degrees of coax to one or the other to beam uni-directions.  You'd be channelmaster on 10M ... ;)

Try modeling that, Steve.

T

Swine business. Here's a pair of stacked dipoles spaced 0.25 WL and phased at 100 degrees. There's a nice 7 dB gain and a good F/B. This system beats a single vertical by as much as 13 dB! That is huge.   ;D

Wow, very nice pattern for west USA work. The TO angle is at about 15 degrees, which is about right. For Eur and beyond, probably 7-10 degrees is better on 10. That wud require another vertical stack. Since there is a small lobe starting to appear in the vertical plane, more height will not help without adding more high angle stuff too.

The equivalent of this wud be a pair of stacked 2el Yagis. If one has a tower, that may be easier to erect. But if trees are the supports, then the wire dipoles may be best.   Though, I've often thought that using a pulley system to raise up two stacked 2el 10M aluminum Yagis using a big tree branch wud work too. Just tie them off to ground stakes and Armstrong rotate them.  Wouldn't that be cool?

T

I wonder how .25 spacing would be in actual use as thats not a normal spacing for dipoles. Mutuals may require a lot of tweaking to get the phasing to match the software.

If that spacing really works I'll try it on 80 and 160!

The stacked dipoles are vertically spaced 0.5 WL. The two stacks are then spaced horizontally spaced 0.25. I don't know if this horizontal spacing is optimal. I just picked it and tweaked the phasing for the best pattern. In reality, it would probably be more practical to just stack a couple of two-element Yagis or Moxons.

The stacked Moxons (red line) have ever so slightly less gain and the F/B is not at good when compared to the phased-stacked dipoles (dotted line). But the feed arrangement would be much simpler. I did not tweak the Moxon design. I think you might be able to get better F/B.

I've got a 3 element Wilson cb beam that I pruned for 10 it works great.

73 N8QPC

I added a 16 ft 10M dipole element in parallel (as you suggested a few years ago) to my ladder-line fed 135 ft dipole.    It works great on 10M, the pattern is almost that of a dipole on 10M according to EZNEC and my experience with.

Hi Bob,

I almost forgot about that technique for use here. Yes, a good solution to mimick a single dipole pattern for 10M using a big Zepp.  Depending on the freq, the overall pattern will not be a perfect figure-8 due to the Zepp interaction, but will be reasonably close.

Thanks for mentioning it. I'll bet some of the guys may try it too.

T

I added a 16 ft 10M dipole element in parallel (as you suggested a few years ago) to my ladder-line fed 135 ft dipole.    It works great on 10M, the pattern is almost that of a dipole on 10M according to EZNEC and my experience with.




would that work ok scaled for 15 meters.

Did you check the coupler settings to load the 135 footer on 10 before adding the 16 footer?

I used the 135 ft for years before adding the 10M element.  The tuner settings were changed but that has nothing to do with the performance of the antenna.    I suppose adding a 15 meter dipole would be good for 15M.   The best thing is to model it using EZNEC and compare the patterns with those of a simple dipole at the same height.   I was mainly interested in 10M, the 40M and 80M patterns are not changed.  The other bands do not seem to have any advantages by adding the 10M dipole.

The reason I asked is it is possible for you to use either wire on 10 depending on your coupler settings. One setting will match the 135 foot antenna and another will match the 10 meter resin ant antenna.

You could most likely lose the 10 meter wire and substitute a 15 meter half wave and not experience very much difference in performance on 10.

I thought about that also, but Tom K1JJ set me straight.    It is how the RF current divides itself, depending on the impedance of each dipole element.    There is only one tuning point.   It would be nice if you could vary the tuning and pick out the dipoles to use, but that just isn't what happens.    EZNEC is the best way to see if something would work.   I haven't tried different band dipoles in parallel with the 135 ft dipole using EZNEC.

I just tried a 15M dipole in parallel with a 135 ft dipole using EZNEC.  It would work about as good as a dipole on 15M but the pattern on 10M is about the same as the 135 ft dipole alone.

I don't think that's entirely correct. The coupler and feedline combination should match either wire on 10 meters. Ideally the 135' wire will not accept much energy when the 16' wire is tuned. That depends as you say on the impedance of both. You would want a voltage feed on the 135 foot antenna while used on 10 meters since your 10 meter wire is current fed. 

If you only got one coupler setting with low SWR it may be both wire antennas are radiating on 10 OR one setting is out of range. 


If the EZNEC plot of the 15 meter wire in parallel is correct there may be some benefit in changing the 135' length around by a few feet so it has a different impedance than the 15 meter wire when used on 10.

"You would want a voltage feed on the 135 foot antenna while used on 10 meters since your 10 meter wire is current fed."


Yes, this is essentially the idea. If the 10M legs make little difference then the 135' length needs to be adjusted so that it does not hog power (as a low impedance feedpoint) and produce that octopus lobe pattern on 10M.

Probably the best starting point is to model the three dipoles together and change all lengths until you see the best figure 8 patterns on the two higher bands. (10M and 15M).  The final lengths may surprise us and the patterns will be a compromise. I haven't modeled this specific antenna myself, only other versions - but may do it later today.

After the modeling, of course the real whirl effects are there, like effective height above ground, houses, ground conductivity, other antennas, etc.   But it should be close enuff.

Bob, you could try a reflector behind that antenna for you favorite band and direction too.

T

This would be true if the tuner was at the common feedpoint of the antennas.   I can't see how you could have two impedances at the end of the feedline however.   Interesting to think about, I am no expert on these things.

While you are modeling how about a balanced line fed full wave in parallel with a half wave srtung 90 degrees different in azimuth.

That should yield a steerable pattern by changing coupler settings. Maybe not groundshaking but I don't see why it wouldn't work.

The two feedpoint impedances would be in parallel and would look like one single impedance to the tuner. There would be no way to vary the power fed to the two elements without using two feedlines.

That settles it, otherwise it would drive automatic impedance bridges crazy.

Think about how the ever popular "fan" dipole is supposed to work. Say, an 80 and 40 resonant wire pair fed with coax. Both impedances are in parallel there too but only the current fed wire works. Same idea but.

I'm not talking about a gradual change between radiators. Just one or the other would be used at one time.

So, it's two separate but closely spaced antennas. One is fed and the tuner on the other is "tuned" to vary the directive pattern of both of them as a system. Do I have that right?

You guys are Taylor hybriding each other, right?   ;)

T

EITCH  EYE!!!!!

I was just thinking the same thing and was about to bring it up.

What is this Taylor thing?  I googled it and I got sites about guitars and golf clubs.
This is getting far from 10M antennas now.

No a Taylor won't work here. You hafta use a Theremin capacitor.

I was being serious but forgot each antenna's load needs to be reactive and inhabit a different place on the Smith chart. Both would need stubs.

Make one j- and the other j+. Can you imagine that? Then put them in parallel.

' Make one j- and the other j+. Can you imagine that? '


only the j-

Unreal!

YUP Tom is A CHANNEL master of sorts from 40M up.
90 over sigs into Iraq on 40M not too long ago.
 FRED