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@hotmail.com
From: "Jim & Velma Woods" <woods@grantspass.com>
To: "Pat Barthelow" <aa6eg@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@hotmail.com>
To: <woods@grantspass.com>; <towertalk@contesting.com>
Sent: Monday, January 24, 2005 11:16 AM
Subject: Trees, Mountains, 15 degrees...
SNIP:
Jim Woods Said:
From: "Jim & Velma Woods" <woods@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@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@hotmail.com
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers",
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