[TowerTalk] Mountain Peak vs Hillside

David Gilbert xdavid at cis-broadband.com
Sat Oct 31 12:50:36 PDT 2009


I've always heard/read that the signal radiated from an antenna 
positioned several wavelengths down the hillside from the peak of a 
mountain (and pointed away from it, of course) is stronger than the 
signal from an equivalent antenna positioned at the peak of the same 
mountain.  That makes reasonable sense to me since I don't think the F/B 
of a yagi is particularly high for negative angles (i.e., down toward 
the ground) and there must be some influence of that energy, but I don't 
think I've ever seen anything other than a subjective discussion on the 
topic.

Can anyone point me to an analytical discussion of that kind of 
situation, or has anyone ever made a real-world comparison?

EZNEC doesn't model irregular terrain and HFTA ignores everything to the 
rear of the antenna.  There may be ways to trick one of those 
applications into looking at it, but so far I haven't figured one out.

Thanks much es 73,
Dave   AB7E




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