[NLRS] Antenna height question

[James Duffey]

Arliss - You can use two Internet apps to get a terrain cross section between your QTH and the Twin Cities. Google Splat! At W5GFE's web site or the online version of Radiomobile. I use Splat!  Splat! Generates a path loss as well, which used to be fairly accurate when it used the longley-Rice model, but they substituted another model which is less accurate for longer distances. The terrain maps are still useful though. 

Having said all that, I suspect that the 72 ft position will be OK, although higher is better. But you knew that
James Duffey
Cedar CrestNM

On Aug 20, 2012, at 2:48, Arliss <w7xu at iw.net> wrote:

> 
> 
> I'm looking for advice on antenna height for antennas for 902 
> through 10 GHz.
> 
> The ground around my home is level to downsloping out to a mile 
> away in any direction.  However, pointing to the Twin Cities, the 
> ground from 1 mile out to 15,000 ft away gradually slopes up to a 
> maximum of 100 ft. above my ground level.  Beyond 15,000 ft. 
> away, the ground is lower again.
> 
> I have two spots available on a tower for my 902 MHz - 10GHz 
> antennas -- 72' and 112'.  Everyone around here knows the 
> problems we can have with ice and wind, and from that standpoint, 
> as well as just the ease in putting the antennas up and keeping 
> them up, 72' is better than 112'.  But does anyone have any 
> guesses as to how much I'll be giving up signal strength-wise if 
> my antennas are 30' below a ridge that's 3 miles away instead of 
> being level to slightly above the height of the ridge?
> 
> By the way, if my calculations are correct, if I'm at 72' on my 
> tower, that 100' high ridge is less than 0.2 degrees above level.
> And the approximate distance from here to the Twin Cities is 
> about 200 miles.
> 
> I'm not expecting anyone can give me anything like an exact 
> answer, just something along the lines of "10 GHz into the Cities 
> will be pretty tough if you don't have the antenna above the 
> ridge," versus "you'll never see/hear the difference between 72' 
> and 112' on any of those bands."
> 
> Thanks & 73,
> 
> Arliss  W7XU
> 
> 
> 
> 
> 
> 
> 
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