I've been meaning to setup some antennas for satellite operation for awhile here. And since I will probably end up doing it this fall/winder I had a question I was wondering about, before I get the antennas completely built connected up.
I plan on using a circular polarized antenna, for lhcr and rhcr. Since this setup has two coax that your switch a 1/4wave (if I remember right) to either side to create the two rotations in the antenna.
Is there a way I can modify this to feed two radios? so one radio would receive lhcr, and the other rhcr? Or would I be forced to use two antennas to do this?
The only idea I have is to use a signal splitter on each of the two antenna halfs before joining them, then join each of those splits into the cr parts. But I'm not sure if there is a better way to do this without as much loss, or if this might cause a backfeed that would defeat the me from getting any signal at all.
Maybe there is a good writeup of this on the web somewhere, but I have no clue what the proper terms to google it are, and haven't had any luck.
Thanks.
----- Original Message ----- From: "Patrick Domack" patrickdk@patrickdk.com To: amsat-bb@amsat.org Sent: Wednesday, September 23, 2009 4:11 AM Subject: [amsat-bb] Antenna Polarization
I've been meaning to setup some antennas for satellite operation for awhile here. And since I will probably end up doing it this fall/winder I had a question I was wondering about, before I get the antennas completely built connected up.
I plan on using a circular polarized antenna, for lhcr and rhcr. Since this setup has two coax that your switch a 1/4wave (if I remember right) to either side to create the two rotations in the antenna.
Is there a way I can modify this to feed two radios? so one radio would receive lhcr, and the other rhcr? Or would I be forced to use two antennas to do this?
The only idea I have is to use a signal splitter on each of the two antenna halfs before joining them, then join each of those splits into the cr parts. But I'm not sure if there is a better way to do this without as much loss, or if this might cause a backfeed that would defeat the me from getting any signal at all.
Maybe there is a good writeup of this on the web somewhere, but I have no clue what the proper terms to google it are, and haven't had any luck.
Thanks.
Hi Patrick
What you propose to do is possible in theory but you need four 3 dB power dividers with characteristic impedance of 36 ohm each and 14 N/m male connectors so that the total losses of the system are too high. I suggest to switch from RHCP to LHCP over the same receiver using only a coax relay as described in all antenna books of the ARRL or into "The Satellite Experimenter's Handbook by Martin Davidoff K2UBC edited by the ARRL
73" de i8CVS Domenico
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