[TowerTalk] Re: Trees, Mountains, 15 degrees...

[Jim Jones]

Pat
What effect does a tall tower (100+) have on these angles?  Seems to me 
a small change in elevation on 1 end would make a big change in angle a 
few miles away.

73    Jim

Pat Barthelow wrote:

> Hello again Jim,
> I am assuming you gave me True azimuths, not magnetic azimuths...
> Your more detailed figures detail the vertical angles over the two 
> mountains as follows:
> Red Mountain:                6.5 deg vertical angle   at 45 degrees 
> azimuth
> Walter Mountain             12 deg  vertical angle   at 91 degress 
> azimuth
>
> Certainly the Walker mountain elevation is significant, and Red 
> Mountain significant, though less so.
> You should download  the free propagation program called W6ELProp  It 
> will draw a Beam heading map for your location, for all locations on 
> the globe.  The parts of the world that are affected by those two 
> directions and points in between, are generally Central Africa through 
> South Africa.
> Other local elevations can be shot with respect to azimuths, and the 
> corresponding world locations can be determined from W6EL prop.  You 
> should still be able to work the African Continent, but it will be 
> harder to do than if you had a low elevation angle to the horizon.
> Remember, just have fun...and if the West has a low horizon, you 
> should be able to work the Pacific, Asia, Australia etc with no 
> problem...
>
> 73, de Pat aa6eg at hotmail.com
>
> From: "Jim & Velma Woods" <woods at grantspass.com>
> To: "Pat Barthelow" <aa6eg at hotmail.com>
> Subject: Re: Trees, Mountains, 15 degrees...
> Date: Mon, 24 Jan 2005 15:44:50 -0800
> Pat, thanks for your reply.
>
> Thanks for the reply.  I just checked my topo map (or is it chart)
> and actually there are two mountains nearby.  My elevation is 1080 ft 
> ASL.
>
> 1.  Red Mountain is 2410 ft. ASL at the peak and bears 045 degrees.
> The peak is ~2.5 miles from my place.
>
> 2.  Walker Mountain is 3866 ft. ASL at a bearing of 091 degrees and
> is 2.7 miles from my QTH.   Think that Walker Mountain is the larger 
> concern.
> Most of the trees here have needles year round rather than leaves.
> Thanks for your input ... any additional comments are most welcome.
> BTW, in the summer months we miss the sunrise from our kitchen
> window due to the darn mountain!
>
> 73,  Jim W7PUP
>
> ----- Original Message ----- From: "Pat Barthelow"
> <aa6eg at hotmail.com>
> To: <woods at grantspass.com>; <towertalk at contesting.com>
> Sent: Monday, January 24, 2005 11:16 AM
> Subject: Trees, Mountains, 15 degrees...
>
> SNIP:
> Jim Woods Said:
> From: "Jim & Velma Woods" <woods at grantspass.com>
> Also, a few miles away is a mid-sized mountain which is east of my site.
> I used a topo map to determine that the top of the mountain forms
> an angle about 15 degrees above the horizon.  Is this high enough to be a
> concern?    Thanks for your input.
> Jim, W7PUP woods at grantspass.com
>
> Hi Jim,
> 15 degrees above the horizon is a very large  vertical angle.   I
> checked what 15 degrees means at 3 miles and computed an elevation
> difference of about 4000 feet, in 3 miles.
> Just to check the math, is your mountain to the east,  4000 feet
> higher than you are?
> If so...it will be a problem for low angle DX signals, as
> previously mentioned.
> 73, de Pat, AA6EG  aa6eg at hotmail.com
>
>
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