On 11/30/11 4:47 PM, Andreas Hofmann wrote:
> Hi,
>
> I have decided I need a tower to get better antennas up in the air. Thinking
> about the SteppIR DB 18, 40m 2 el, 20 and up 3el. Now, my property slopes
> pretty much in every direction by 5 degrees. I need to determine a proper
> tower height without breaking the bank.
>
> I was told I should run a computer program to figure a good height of the
> yagi for my most important directions/DX locations. In fact a friend of mine
> did the same (on a similarly sloping property) and he found out that a 55
> foot tower would be similar to a 120 foot tower on a flat ground. Hence he
> put up a 55 foot crank up mast and it is rocking. He forgot the program he
> used.
>
> So, what tool can I use to find the optimal (not maximal) height of a tower
> that would work well here?
> Also, the tower would be setting on the side of the house with a metal roof
> (roof about 15 feet high), not sure if this would matter...
>
> Thanks
> Andreas
> KU7T
>
HFTA by Ward Silver which comes with the ARRL Antenna Book is what you
want. You enter in the surrounding terrain (or extract it from DEM
files, etc.) and it calculates the pattern.
Only works for horizontally polarized antennas, by the way.
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