Sat antenna fixed elevation -- how many degrees is the best?
I've seen people with fixed elevations of 25, 30, 35 degrees, any consensus on which is the best? 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?
73, Bill NZ5N
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On Feb 19, 2008, at 9:52 AM, Bill Dzurilla wrote:
I've seen people with fixed elevations of 25, 30, 35 degrees, any consensus on which is the best? 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?
I had a contact a couple weeks ago with ISS. I used an Arrow II 2m antenna mounted on a tripod, and my friend handled the pointing. While I understand this wasn't strictly necessary, it was part of the fun.
Later we discovered that the compass we used as a reference was magentically reversed, and we were pointing in completely the opposite direction from ISS. We were always able to hear ISS, but there were times when ISS couldn't hear us. In the end, we probably shouldn't have bothered.
For more distant satellites, it probably makes more difference.
At least, now we finally know which way North is, generally, at our location.
I've seen people with fixed elevations of 25, 30, 35 degrees, any consensus on which is the best? 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?
Hi Bill,
I assume you are rotating in AZ.
Determine your beam width, divide by two, and that is your EL. I would tend to favor the horizon, obviously the greatest range.
I use home brew quadrifilars, rotate with a little TV rotor, 2M and 70 cm on the same mast. By experiment, I determined the beamwidth ~65°, so I fixed EL at 30°.
And if the satellite downlink is strong enough to be heard at all I get the entire pass....
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73, Dave, WB6LLO dguimon1@san.rr.com
Disagree: I learn....
Pulling for P3E...
----- Original Message ----- From: "Dave Guimont" dguimon1@san.rr.com To: "Bill Dzurilla" billdz.geo@yahoo.com Cc: amsat-bb@amsat.org Sent: Tuesday, February 19, 2008 12:48 PM Subject: [amsat-bb] Re: Sat antenna fixed elevation -- how many degrees is the best?
... I use home brew quadrifilars, rotate with a little TV rotor, 2M and 70 cm on the same mast. By experiment, I determined the beamwidth ~65°, so I fixed EL at 30°.
And if the satellite downlink is strong enough to be heard at all I get the entire pass....
My observations mirror yours exactly, except that I find directly overhead to be fairly hard to hear(no pre-amp) so I avoid direct-overhead passes, or wait untill it's gone past to start talking. Since I am controlling the radio and rad-shack rotor manually, doppler and azimuth are too fast going overhead for me to track anyways. I also happen to use a little less elevation, which doesn't help the overhead part one bit! I think it's a nice compromise untill I can afford a new rotor system.
73's Auke VE6PWN
participants (4)
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Auke de Jong -
Bill Dzurilla -
Dave Guimont -
Rick Mann