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*Subject*: [amsat-bb] Re: Sat antenna fixed elevation -- how many degrees isthe best?*From*: "Robert Bruninga" <bruninga@xxxxxxxx>*Date*: Tue, 19 Feb 2008 18:37:05 -0500

>> I've seen people with fixed elevations of 25, >> 30, 35 degrees, any consensus on which is the best? No more than 10 or 15 degrees above the lowest horizon you can see. See http://www.ew.usna.edu/~bruninga/rotator1.html >> And how well, if at all, does an antenna with a >> fixed elevation of 30 degrees or so perform when >> the sat is higher than 60 degrees? Doesn’t matter. Satellites are only above 60 degrees less than 2% of the time and then they are 10 dB closer and so strong you don’t need any gain. > Determine your beam width, divide by two, and > that is your EL. I would tend to favor the > horizon, obviously the greatest range. That approach would make the gain at the horizon (where it is needed most) be always 3 dB down. And it would give maximum gain (at 30 deg) where it is needed least (where the satellite is already 6 dB stronger). Remember, any LEO satellite spends 70% of all access time below 22 degrees or so, and so having maximum gain down on the horizon is most important. > By experiment, I determined the beamwidth ~65°, so I fixed EL at 30°. That's giving up 3 dB at low elevations where the satellite spends the majority of its time. It would be better for a lot more of the time if it was no more than 15 degrees abouve your lowest horizon. IMHO Bob, WB4APR _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

**References**:**Sat antenna fixed elevation -- how many degrees is thebest?***From:*Bill Dzurilla

**Re: Sat antenna fixed elevation -- how many degrees isthe best?***From:*Dave Guimont

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