So long as antenna discussions on the reflector haven’t been met with the “OT” cloture lately, I have an antenna question of a different sort. I am contemplating a ¼ wave vertical with four elevated radials for 80 meters. My choices for siting it are two – one is near the top of the property (about 8,600 feet ASL), somewhat in the clear, and within 100 feet from the operating position. The other is in a meadow near the property boundary, which is much more open and a just a bit higher – but it has two other significant characteristics. One is that the land slopes away from that site, over about half the compass from NNW to SSE, at a slope of 10 to 15% for about a half mile. According to ON4UN’s text, that slope could give me a significant gain in that part of the azimuth with no significant terrain obstruction on the other half. The second characteristic, however, goes the other way – that site would require about 500 feet of feedline from the house to the antenna feed point. I have been looking at the loss factors in hardline and in “direct burial” coax, which on 80 meters seem modest but not irrelevant for a run of that length – maybe a dB or so per 100 feet. What I can’t quantify – because I don’t have enough life expectancy to learn how to adapt antenna modelling software to a Mac or even to learn it if I could – is whether the gain from the sloping near field would make up for the feedline loss. In case it matters, the ground likely has very poor conductivity. It’s decomposed granite – a specialty in the Colorado mountains – with a very thin layer of usually very dry soil. (Our well has a static level of 142 feet, so there’s no ground water anywhere near the surface.) Anyone have opinions, guesses, estimates, advice, or whatever – should I accept the feedline losses and enjoy the half-hemisphere low-angle gain? Or would the poor soil quality negate that advantage?
Ted, KN1CBR ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
