Comet CX-902 as sat antenna?
Hi,
I'm trying to help one of the local Honduran hams get started on the sats. He has a dual bander and a Comet CX-902 vertical antenna, 9 db gain, about 35' in the air. We set up to work tonight's AO-51 pass but did not hear a thing. About halfway through the pass, when it was obvious we were not hearing the bird, we switched the antenna from his rig to mine, just to verify that the rig was not at fault. But we still heard nothing. This suggests to me that the problem is the antenna or feedline. Is there any reason why the Comet would not work at all on the sats? He can raise the local repeater with this antenna.
73, Bill NZ5N
PS - Several of the Swan Island guys were intrigued by my sat operation and we hopefully we have a few more HRs active soon.
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When we go back to antenna theory, we find that to get gain from a vertical antenna we reduce the height of the donut around the antenna, thereby increasing the diameter of the donut. The donut represents the coverage of the antenna in azimuth and elevation. The area of the donut represents the power of the transmitter or the sensitivity of the receiver. We change the dimensions of the donut with antenna gain, while the volume remains constant. The higher the vertical antenna gain, the thinner the donut and the larger the diameter. Since the satellite is above you, and the vertical antenna has gain, you will not receive the satellite unless the satellite is near the horizon.
To receive the satellite with a simple vertical, use a unity gain ground plane. This will work for all but the passes directly overhead.
73 Glenn WB4UIV
At 10:37 PM 3/22/2008, Bill Dzurilla wrote:
Hi,
I'm trying to help one of the local Honduran hams get started on the sats. He has a dual bander and a Comet CX-902 vertical antenna, 9 db gain, about 35' in the air. We set up to work tonight's AO-51 pass but did not hear a thing. About halfway through the pass, when it was obvious we were not hearing the bird, we switched the antenna from his rig to mine, just to verify that the rig was not at fault. But we still heard nothing. This suggests to me that the problem is the antenna or feedline. Is there any reason why the Comet would not work at all on the sats? He can raise the local repeater with this antenna.
73, Bill NZ5N
PS - Several of the Swan Island guys were intrigued by my sat operation and we hopefully we have a few more HRs active soon.
Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ _______________________________________________ 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
participants (2)
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Bill Dzurilla -
Glenn Little WB4UIV