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I don't have an HOA, but I don't: a. have the space outside for an 80 meter dipole, nor: b. does my wife want visible antennas on the outside of the house. So I've been in the mode of finding an indoor antenna that works, and is cheap. I strung a 29 foot end fed antenna around the ceiling of my sun porch and it reached Hawaii on WSPR on 2watts, and it received from Europe on FT8 (not set up for transmit yet). I can't keep it there because, well it's our sun porch.

I thought I'd improve things by putting up a 40m OCFD around the perimeter of the ceiling of my garage... work in progress.

But I really wish for an 80m OCFD. No way to fit 40 meters of wire in my garage, but the question above came to mind.

I definitely have room in the basement for 40 meters of wire. My basement has very high ceilings so it'd be up about 12 feet from the concrete floor, but really only about 1 to 2 feet above outside ground level.

Thus my question. Would this work at all? I don't need great results...

I already know there are other indoor and stealth alternatives... but I still have this question about a basement antenna.

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  • $\begingroup$ I could try it, but was looking if there was an answer such as "it can't possibly work at ground level" $\endgroup$ Feb 1 at 2:05
  • $\begingroup$ Hello and welcome to ham.stackexchange.com, @scm! $\endgroup$
    – rclocher3
    Feb 1 at 14:51
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    $\begingroup$ Someone on this forum reports success with a buried HF antenna. If a buried antenna works, an antenna a foot or two above ground level should work. The only question is, will it work well enough for you? $\endgroup$
    – rclocher3
    Feb 1 at 16:25
  • $\begingroup$ That is very interesting and something I think I'll try in the spring. $\endgroup$ Feb 1 at 17:06
  • $\begingroup$ Do you have an eavestrough you can try? $\endgroup$
    – VE3LNY
    Feb 2 at 15:23

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This is one of those cases where theory can only take you so far, and practice is the rule of the day.

The problem is that my practice will rarely match with your practice. Propagation is complicated and surprising, and everything around your house from the earth to the sky (and beyond, for some propagation!) will have some effect. So no one here can say for sure if your dipole in your house in your neighbourhood won't work.

So, I say: try it.

Heck, as pointed out in the comments, people experiment with ground and buried antennas and get repeatable decent results. Ground antennas are often only used for receive but I bet that's more of a safety issue than any technical reason.

Sure, it won't be ideal. But you say you don't need great results. I suppose your actual question is, will you get any results, or just hash? That question no one here can answer, unfortunately, because there are too many variables. Maybe you get just the right lobe at the right inclination to bounce off a nice patch of ionosphere that just happens to be nicely irradiated by the sun.

This might be where propagation modelling software might help you, if you can figure out how to model how the lobes will be deformed by walls, ceilings, etc. My guess is that is a hard problem, but I'm certainly not an expert on this.

But radio history is full of non-ideal antenna situations working out in surprising ways. I'm thinking specifically of all those stories about secret spy operators behind enemy lines trying to send messages stealthily when life-threatening constraints kept them from stringing up the ideal suitable long wire outside where enemy eyes could see it.

I won't mention construction, feedlines, safety, tuning, etc. because one assumes you are already thinking of that and will raise further questions if necessary.

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    $\begingroup$ Thanks. I'm encouraged to just go ahead and try it... given what I have on hand, I just need to order a balun.. I'll report back with an answer how it works. $\endgroup$ Feb 1 at 16:26
  • $\begingroup$ I guess the tricky thing is assessing impedance. The perfect dipole is, what 73.1ohm? But it changes with wavelength from the ground. I don't know in this case if you are 0 from the ground or (-)-wavelengths from the ground in the basement! I guess your wife didn't realize that banning ext antennas means now you have a budget for an antenna analyzer. $\endgroup$
    – user21417
    Feb 1 at 16:35
  • $\begingroup$ Your idea of a basement antenna has made me look into caged dipoles. Very interesting! $\endgroup$
    – user21417
    Feb 1 at 16:41
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A large or full wave loop antenna at ground level often works well for lower band HF reception (research LOG or loop-on-ground antennas), sometimes due to lower RFI/EMI noise pickup, but has very low (highly negative) gain when used for transmit due to ground absorption of any horizontal radiation lobes.

DOGs (or dipole-on-ground) antennas are another possibility, close to a basement ceiling configuration.

The military has experimented with ground level (thus blast resistant) cavity antennas, or slot antennas, which might be approximated by a basement excavation with a suitable conductive ground plane at basement floor level plus a radiating slot above.

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  • $\begingroup$ Tunable and steerable slot antennas would be really useful for EME or satellite comms. And now I have another rabbit-hole to fall down... $\endgroup$
    – user21417
    Feb 1 at 22:05
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    $\begingroup$ I use a LOG (invisible in the back lawn) for HF receive. For slot antennas, look into John Portune's (W6NBC) book on such. $\endgroup$
    – hotpaw2
    Feb 1 at 22:12

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