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Author Topic: Vertical antennas and chain link fences  (Read 13962 times)
N7GTE
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Posts: 9




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« on: March 27, 2003, 01:33:19 PM »

I would like to get feedback from any fellow hams that have had experience with mounting vertical antennas on/above/near chain link fences and use the metal fence as part or all of the ground radials. I am particularly interested in comments about Butternut verticals used in this way.
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KG4YWS
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« Reply #1 on: March 27, 2003, 01:42:45 PM »

I would also like to know something about this item.  I am looking at installing a Hustler 4-BTV vertical to a line post of a chain link fence.  KK5VL had mentioned it in his eham.net review of the 4-BTV.  I would really appreciate knowing how it is best done. Thanks.
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WB2WIK
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« Reply #2 on: March 27, 2003, 01:45:03 PM »

I've had a lot of experience with this, but unfortunately, it's almost all bad!

Best results I've had with HF verticals and chain link fences is to get the vertical as far away from the fence as possible, and then use ordinary radial wires under the vertical.  I've never yet found the situation where a chain link fence, regardless of layout, length, height or construction, could make a reasonable counterpoise for an HF vertical.

WB2WIK/6
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K0BG
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« Reply #3 on: March 27, 2003, 01:57:57 PM »

I second Steve's comments. And if it did work, you would have a skewed pattern. And another fact of life, few amateurs install enough of a groundplane to really make a difference. It takes at least 40 and preferably 60 or more radials to make a 1/4 wave vertical work like it should.

And if you choose a loaded 1/2 wave instead which typically doesn't require much of a groundplane, you have to be keep it as far away as you can from anything metallic, or it won't work very well either.

Unless you live on one of the coasts, you're almost always better off with a dipole.

Alan, KØBG
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KT8K
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« Reply #4 on: March 27, 2003, 02:39:10 PM »

Sounds like it will work with an appropriate system of ground radials.  The steel used in the fence itself is probably a pretty poor excuse for a ground, radials, or anything else conductive, even if you bonded all the joints, which would be a pain.  The posts are certainly sturdy enough to hold your vertical, though.
Good luck, and hope to hear you on the air.
73 de kt8k - Tim
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WB2LCW
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« Reply #5 on: March 27, 2003, 03:24:51 PM »

I jury rigged a 17 meter vertical last week! It is 12 inches above a six foot chain link fence. It has one wire radial. I had seven Qsos with it, Belgium,Atlanta,New Mexico,Montana,California,New Hampshire,and the Galapagos Islands!

73 Mike
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W0FM
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« Reply #6 on: March 27, 2003, 03:58:38 PM »

Hi Bob,

Back in the late '70's I had nowhere else to go with my Hustler 5BTV, so I clamped it to one of the 3ft vertical supports on my chain link fence.  The base of the 5BTV was about 6" above the ground, so around 30" of the lower element (10M section) of the vertical was parallel to the fence post (not good!)and just inches away from it (even worse!).  I drove a ground rod in near the base of the antenna and extended a handfull of radial where I could.

I made no effort to use the fence itself as a counterpoise.  The points where the chain links crossed each other were (obviously) galvanized and sported many coats of paint over the years.  Even if I totally believed that the fence might substitute for a radial system, I could assume no DC continuity anywhere along its length.  So, I viewed the fence as nothing more than a convenient support that wreaked havock with my signal.  I was probably quite correct!

I'm sure the performance was compromised and the pattern was skewed (particularly on 10M), but I made many contacts with that arrangement.  If you have no other options, it will be better than no antenna at all.

73 de Terry, WØFM

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K6QP
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« Reply #7 on: March 27, 2003, 04:39:27 PM »

I am 2 weeks into using a butternut vertical, ground  mounted about 20 feet away from a chain link fence. I installed the ground radial kit from butternut, and did not use the fence as any part of the radial system. My results are all continents several times over and I blanket the US very well.  Several of my radial wires run under the fence. Hope this helps.
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K0BG
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« Reply #8 on: March 27, 2003, 05:39:10 PM »

The key word here is: Efficiency.

The truth is, it doesn't take much power (radiated) to make contacts as any QRP operator will tell you. And the average 1/4 wave vertical user, if he/she really knew the truth, is operating QRP even with 1000 watts to the antenna.

A 1/4 wave vertical antenna with a minimum radial system (or none at all) will indeed make contacts. Lots of them in fact. But...if you really want a vertical to work well, it MUST have a groundplane, and one or two radials (or a chainlink fence) is not a groundplane.

Efficiency is hard to measure even with the best of equipment. But if you ever get a chance to operate with a vertical with an adequate groundplane (in my case 120 radials over 80 feet in length) it'll become glaringly evident of the difference between none and a lot.

Alan, KØBG
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WA4PTZ
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Posts: 527




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« Reply #9 on: March 28, 2003, 05:34:48 AM »

I played with this concept back in the late 70's
and the other folks are correct about the skewed
pattern. It can and does work , however, The trick is
to be sure your radiating surfaces are at least 12
inches above the fence and wind an air balun of 6-8
turns of coax about 6 inches in diameter and about
12 to 14 inches from the antenna. I was fortunate to
have good neighbors and I talked them into letting
me connect all the fences in the area. WOW! what a
radial system. It was fun to play with but the
standard buried radial system is easier to
accomplish and maintain.
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N0HR
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« Reply #10 on: March 29, 2003, 08:56:26 PM »

This topic has been discussed off and on (and I was in exactly the same boat as you). I have yet to see someone to go to the extent of using modelling tools or field measurement equipment to try and determine the impact.

As I had previously mentioned in another thread, I'm a Butternut owner in the same situation. Luckily, I was able to mount my antenna completely clear of anything else (nearest house ~100' away, no power lines, just an open spot). http://www.eham.net/forums/Elmers/18443

I mounted the antenna on a 5' metal post (EMT) clamped to a fence post and guyed. Works pretty good as far as I can tell. Used an MFJ259 to tune.

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WB0BBC
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Posts: 19




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« Reply #11 on: April 09, 2003, 12:07:31 PM »

I too have mounted both trap verticals and Butternut verticals onto the support posts of chain link fences.

The results have worked quite well.  I placed the vertical as near to the center of the fence section as I could.  Several U-bolts were used to fasten the antenna mount to the vertical fence post.  I also placed ground rods at the ends of the fence sections and fastened grounding straps made from RG8 braid to help ground the fence structure.  I also mounted a ground rod directly below the attenna and grounded the base of the antenna to it.

This worked well for several years at several QTHs in the Midwest and in South Florida.  The SWR was good.  I can't tell if the radiation pattern was altered.

Give it a try -- it's inexpensive and does work.
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KA7NIQ
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« Reply #12 on: October 15, 2013, 09:00:47 PM »

Us Hams use what we have, and sometimes, using a chain link fence as a counterpoise for our verticals is one option we can try.
I know of several Hams here in the Tampa Florida area, using Verticals on chain link fences, some with decent results too.
Especially if the vertical can be mounted at the intersection, where a bunch of chain link fences come together!

I know Hams using mobile homes metal roofs as counterpoises for verticals, and another Ham here uses a Butternut, and his pool screen room as a counterpoise.

LOL, another Ham here needed a new roof, so he had it replaced with a metal roof! He has a Hustler 4TBV on the roof vent pipe for his toilet, and uses his entire metal roof as a counterpoise.

Another Ham here near Tampa roof mounted a vertical, and used his aluminum fascia/gutters as a Counterpoise.

Every winter, many Hams come down here to Florida, some with Airstream Metal Trailers, and use them as counterpoises for their verticals.

The bottom line ? We do the best we can do, with what we have, and accept the compromises.

But sometimes, what we are told "will not work", does work, and works surprisingly well!

If the Chain Link fence is there anyway, WTF is the harm in erecting a vertical on one of it's vertical poles, and giving it a try ?





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