On 1/19/19 6:58 PM, john@kk9a.com wrote:
That is a great question, I have wondered this many times when operating on
the sloping terrain in VP2V and KP2. To my knowledge there is no modeling
software that will show a vertical's pattern on a hill.
No readily available amateur radio software..I'm sure that there are
codes out there.. Maybe HFSS could do it, but I'm not sure it's well
suited to this.
If it is a "uniformly sloping hill", you could put a vertical that
slopes at the hill angle into NEC and model with flat earth. - then
rotate the pattern you calculated.
But once you get away from that, it's trickier. You can do a fairly
straightforward raytrace for H pol, the reflection coefficient varies
smoothly and is generally large, and the usual assumption is that the
soil surface is parallel to the polarization.
V pol reflection coefficient varies a lot, and you need to deal with
things like diffraction.
John KK9A
Tom Osborne w7why wrote:
Hi All
I have tried putting up an 80 meter vertical 3 or 4 times. No matter what
I do, it is never better than my twinlead fed 80 meter dipole up about 65
feet.. This is both on close in stuff and longer range propagation.
I tried it with the radials on the ground, with the feed point elevated
about 6 - 8 feet with 4 raised radials, and about every combination I can
think of.
I was wondering if living on the side of a 450 foot hill makes a
difference? The hill slopes down to the bay below my house.
I have a 20 meter HB beam up about 25 feet. f I walk to the east about 25
feet, and look back, the 20 meter antenna looks like it is about 60 feet
up. Goes higher as I walk farther east down the hill.
Do verticals work poorly on the side of a hill, or does it make any
difference at all?? Thanks and 73
*Tom W7WHY*
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