After seeing people ask online if they could string a wire on top of their fence and use it as an antenna, I decided to see how it would work. While there are definitely better antenna options available, this method can get you on the air, especially if you're living in a strict HOA environment. However, be cautious about placement to ensure no one can get too close to the wire and do your exposure calculations. Would be best to not put it on a shared fence. Additionally, keep in mind that if your fence gets wet, it will detune the antenna significantly.
This fence antenna worked until it was decommissioned in 2013. https://www.google.com/maps/@33.556...a39cw!2e0!7i16384!8i8192?coh=205409&entry=ttu Rotate the view around to the south. The other half of it is on the other side of the road.
If your fence is metal, mount a motorized screwdriver antenna on it, using it as the counterpoise. 10-80 meters, 1.5:1 SWR (or less) across all frequencies. Low enough profile so no one should complain. You’ll be surprised how well it works.
My Icom AH-4 random length wire auto tuner has tuned a fence, gutter, defunct telephone line, car door, farm gate, rain water tank and a metal roof.
His wire on that fence is very inefficient, it's heating up the worms. It still might receive pretty good, and he may have low SWR. So it also works as a good dummy load.... .. You can get about anything to load up, and make some contacts, but it's questionable if it's a good antenna or not!! The laws of physics apply, no matter what your SWR is. He made some good points about not using on a shared fence for safety reasons. Also rain and weather conditions would be a constant loading problem. A vertical mounted on there using the wire on the fence as a ground system system, would be a better choice.
Any antenna is better than no antenna. Verticals or using trees might not be allowed or safe in some settings. One can make contacts with a low NVIS antenna, even at QRP power levels, possibly even some DX with FT8 or CW. The portion of the pattern opposite the worm heating does radiate upward for NVIS, often better than a vertical for local HF. For receive, a lower noise antenna is better than a high noise one (if you can't hear 'em, you can't work 'em). And, in urban settings, a low horizontal antenna, or even one lying on the ground, might show better weak signal SNR than a vertical. My WSPR antenna is a back fence EFHW at 7' AGL, and using only 1 Watt, occasionally gets spotted by distant DX.
I never said you couldn't make contacts, in fact I said you could. I totally agree with you, the Best antenna is one that's On the Air and making QSOs. The frustration level can be higher though, with such a low configured system. The laws of physics apply, no matter what your SWR is.
Has anyone compared the pattern efficiency of a low NVIS horizontal (40M EFHW) vs. a short vertical such as a rear bumper screwdriver or 7' hamstick?
I can't give you pattern efficiency between the two, but I can give my experience. In my HOA, for years I've been running a Tarheel screwdriver mounted directly in the middle and on top of a 70'x 6' steel fence bordering the back of my property, using just that as a counterpoise. The tube that encases the motor and coil is 4 feet, and the whip is 6'...not enough visibility to rattle anyone's cages in the neighborhood nor the HOA. In my post above, I indicated its SWR all over 10-80 meters...no tuner needed. In the case of a wooden fence, just run a series of radial wires, fanning directly out beneath the antenna both ways along the fence. Ignoring stats like radiation pattern and efficiency, I've worked all over the world in CW, SSB, and RTTY contests, running 100W. I don't do FT8 or any other digital stuff. No muss, no fuss, easy install. That's what counts...*reliably working stations* with a low profile, low footprint antenna, not affected by the elements of weather. I have another screwdriver ground-mounted high on a hill behind the house, hidden in desert brush, with sixty 25' radials stapled to the ground, running legal limit. Close to 300 countries worked and decent contest scores...obviously a more optimal location than the one on the fence.
There are almost always better solutions than running a horizontal wire on a fence six feet above the ground without standoffs. No wonder it detunes in the rain! I'm sure the losses also go through the roof whenever it gets wet. "Everything works," but it's hard to think of anything that would work worse than this. If your fence is not metal, mount the vertical on it and run radials for it along the fence. Use standoffs so rain won't detune the antenna so much. Put it against a background of trees as viewed from the street if you can, and paint the larger elements with camouflage to help keep the HOA away. This antenna will beat the hell out of a poorly constructed fence antenna on most paths. If you have two trees twenty feet tall, you can hang a 40m inverted "L", a 20m vertical, both fed with the same feedline, and a 12/10m "fan" dipole in them. Use small-diameter wire and hang some fake plant twigs and leaves on them and the odds are no one will ever notice them. Above ground radials would work best for the "L" and the vertical. In many HOA situations you can run two above ground radials in opposite directions along a fence using standoffs for god's sake, but if you must use an on-ground/buried radial field, the "L" and the vertical can share it so you only need one. This will give you a fair signal on 40 20, and 17m (you will need a matching unit for 17m), a good one on 15, and a really good one on 12 and especially on 10m, in most directions, with two feedlines. This antenna suite will work all kinds of DX the fence antenna won't even hear and will be much louder than the fence antenna on almost all paths. If you don't have trees, but don't mind putting in a little work to get a good signal out, you can make two 20 ft. fold-over masts out of all sorts of cheap, easily worked, readily available material you wouldn't use for a taller mast, like fence top rail, 2x2, pvc, etc., for the antenna suite described above. A little trial and error will allow you develop a system that can be raised and lowered in a few minutes. Always fold the masts over when the antenna is not in use or the lawn being cut, and camouflage the antennas against their background as seen from high traffic areas, and you are far less likely to have trouble with HOAs or neighbors. And always remember, if you must run an antenna so that it contacts wood of any kind, use standoffs.
I should try that! I've got scads of 100-year-old barbed wire surrounding my 5 acres (used to be a small household farm and field).... just for the heck of it. Dave W7UUU
