On 11/13/2013 12:48 PM, James Setzler wrote:
Anyone else have experience with the HF2V mounted up using elevated radials
versus ground mounted with limited on-ground radials.
Over the summer, I did extensive modeling (NEC) of vertical quarter-wave
and vertical dipole antennas, comparing performance on the ground and at
typical roof heights. A report on that work is on my website in the form
of a pdf of the Power Point for a presentation I did at Pacificon last
month.
http://k9yc.com/publish.htm
The executive summary -- for all vertical antenna types and almost all
soil quality, roof mounting outperforms ground mounting. The advantage
of roof mounting is greatest for the poorest soil, varying from as much
as 8 dB for very poor soil to a dB or so for extremely good soil.
I did one series of signal strength measurements on a real antenna -- a
20M vertical dipole that was first measured with the base at ground
level, then at 10 ft, 20 ft, 30 ft, and 40 ft, and finally with the
center on the ground and the bottom half horizontal (at W6GJB). The
difference between 0 ft and 40 ft was 10 dB over a 5 mile path (to a
vertical antenna at my QTH). The soil at his QTH is quite poor.
73, Jim K9YC
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