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Old December 13th 06, 04:51 AM posted to rec.radio.amateur.antenna
Jimmie D Jimmie D is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 296
Default Angle of radiation


"Sal M. Onella" wrote in message
...

"Jimmie D" wrote in message
...
This afternoon while cleaning a closet I pulled out an old US map that
had
been marked with contacts I made back when I worked 10M a lot. After the
local stations there is a big empty area on the map then I started making
contacts again at about 300 miles. Antenna used was a 1/4 lambda

groundplane
with the radials drooping so to match 50 ohms. A chart I found indicates
that this means I have a vertical angle of radiation of 50 to 60 degrees.

Is
this correct??. I didnt think the angle would be so great for this

antenna.

The gap between the farthest of the ground wave contacts and the nearest
of
the skip contacts is termed the Skip Zone and the 50 to 60 degree number
you
cited sounds accurate. It represents the highest takeoff angle that is
successfully refracted back to earth.

Please note there is no one takeoff angle. It's a range of angles and
your
transmissions at many angles are returned simultaneously. A quoted
takeoff
angle is merely the angle for the strongest signal. For a given paths a
particular takeoff angle may be optimum, but others will still work.



Makes sense, since as I get further away, 600 miles the density of contacts
actually increases.
Seems to be a really strong concentration of contacts in gulf area from
louisianna on toward
texas from here in north carolina.