[amsat-bb] Re: Station not coming together - the full post (sorryfor repost, reply to this)
bruninga at usna.edu
Wed Mar 7 18:33:20 PST 2007
> 11db forward gain, exactly 50 ohms impedance, great bandwidth
> and at 30 degrees elevation, the horizon is 1.5db off
> peak response, and the -10db response on the upper side
> should be around 75 degrees.
BUT, LEO Satellites spend 30% of all in view time below 10
degrees. And less than 2% of their time above 60 deg. AND the
satellite is 10 dB weaker on the horizon than it is above 45
deg. So you do not want to sacrifice anything at the horizon,
and you could use a rubber duck above 45 deg.
So point your beam up 15 degrees. Don't waste any gain above 45
See my page: http://www.ew.usna.edu/~bruninga/rotator1.html
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