I previously had my Rangemaster mounted up on the garage. Last spring, I took it down and transported it to my summer home in Michigan for experiments with ground mounting. While I don’t want to become embroiled in a discussion about the legitimacy of elevated mounting, I have decided that it’s not currently an option for me. Therefore, I’ve been trying to find out what I can do with a ground mounted system.
My experiments at the lake were not exactly earth-shattering. Over there, I have the benefit of a completely clear channel during the daytime– which is great– but the ground conductivity is awful. It’s basically sandy soil. I’m hard pressed to get a usable signal beyond a few hundred feet, although I can detect it on on a very sensitive receiver at a mile or more (at a level that no one would ever listen to).
I brought the Rangemaster back home for the winter and set it up in the back yard last weekend. I have one of those “impossible” situations: average (high clay) ground, a small lot with very little room for a decent radial system, and a crowded dial. At least with my ham radio setup I can get around some of the siting problems by putting antennas up in the air. I do have one ground-mounted vertical; it has never worked that well although on 40m and above, the ground radial system is fairly efficient.
I have more experiments to do, but so far it appears that my Part 15 signal is no worse than when the transmitter was on the garage. I attribute this to a slightly better radial system (there were no radials under the transmitter when it was elevated; just a lightning ground). I am still trying to decide how to construct the capacity hat antenna that I want to try. I also think I might try putting a short (3m) ground screen under the antenna. Since I can’t put out long radials, at least I could try that.
My second transmitter is an SSTRAN. I have that one set up in the living room with its floppy wire draped over the TV set, where it couples into the ac line via the internal degaussing coil. This setup works way better than it has any right to– the signal is surprisingly good on my block. As soon as I go beyond that, it drops into the noise. Inside my house and around my yard, it has a super signal. I use it as a translator for a distant university owned classical FM radio station. This enables me to listen with a strong, clear signal anywhere in the immediate vicinity of my home.
Unfortunately, I think that the “new normal” of being restricted to a ground-mounted system will mean that the idea of “community broadcasting” is dead except for those who have locations with excellent ground conductivity and the ability to deploy a really outstanding radial system. This will not apply to most of us. I am still interested in further refinements to radials and antenna loading, to see what small improvements can be achieved.
What are we left with? For now at least, I have decided to “make a virtue out of a necessity” and use my Part 15 system as a short-range FM translator. If my my closest neighbors want to tune in, they can hear it, but that is about all. Nevertheless, I derive a great deal of enjoyment from it. I think that there are still many out there who will find great uses for short range transmitting to their own or neighboring properties even if “broadcasting” to the community is no longer feasible. More work on ground systems for those with limited space is still needed.