[Elecraft] Sloping Terrain vs Feedline Losses

[Vic Rosenthal]

You might also consider receive noise, which you can check in both spots (unless you are planning a dedicated RX antenna). 
As others said, loss for most coax will be much lower than one dB per 100 feet.

Vic 4X6GP

> On 13 Jul 2016, at 01:16, Dauer, Edward <edauer at law.du.edu> wrote:
> 
> 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
> 
> 
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