Quoting Stargate [email protected]:
Howdy all, Still building up my station but cash is starting to get tight! I was considering the M2 436CP42 U/G and M2 2MCP22 antenna's. I think I'm down to the build-it, instead of buy it stage, so I was wondering if anyone has links to websites with PROVEN designs for a CP beam such as these? I have seen a few sites but I hate to build a CP antenna without prior recommendations from someone else. So, What have you? :-)
Station so far...
FT-847 (computer controlled) G-5500 rotor (computer controlled) LVB tracking board Orbitron tracking software ARR MSP432VDG-160 preamp ARR MSP144VDG-160 preamp
Rod:
I know this doesn't answer your question, but I'm going to suggest that you consider not building CP antennas at this juncture.
I take it this is a beginning station aiming to acquire reliable links with LEO satellites down to the horizon. If that's the case, given your existing investment in the G-5500, I think you can get away with building medium-length linear yagis for each band and calling it a day. As a recent thread indicated, short linearly-polarized yagis on a az-only rotor have done very nicely for many of us. Because of your elevation rotor, you can afford the more narrow beamwidth of longer yagis and enjoy the improved gain. At that point, you simply don't need the additional 3 dB of gain on the downlink, and on the uplink you might come close to transmitting too powerful a signal, even at the lowest setting of your rig.
In any case, this has been my reasoning in upgrading to a 7 element 2m horizontal to match my 8 element 70cm vertical on a new az/el setup. I believe that the complexity of CP switching and phase-line building is sufficient that without great care I'm likely to end up with something no better than the linearly polarized model. By the launch of P3E, I do hope to have a longish (8 el?) CP yagi (this is why I'm going to the bother of the az/el system and the longer antenna), but I want to carefully record the performance of the current 7 element model before adding the second set of elements and the phasing system.
I'd throw together a 5-6 el. 2m yagi and a 8 el. 70cm and enjoy your station ASAP.
73, Bruce VE9QRP