[amsat-bb] Cheap CP 2.4 ghz antenna?
ko6th_greg at hotmail.com
Sun Oct 18 15:12:57 PDT 2009
So I have a pair of 14 dbi flat panel "Wi-Fi" antennas, complete with pigtail and N connector. I assume they're linearly polarized. Satellite downlinks really ought to be circular, if possible.
For satellite use, could I simply mount the two on my Az/El rotor boom, with one rotated 90-degrees from the other, and with a 1.23 inch shim behind it (for the 1/4 wave offset, if I did the math right), then combine the two antennas with a simple "T" connector? The impedance would be wrong, but for Rx only, probably irrelevant. I'd be feeding it into a Kuhne preamp, and from there to the Drake downconverter.
As a receive setup for the likes of AO-40, this probably wouldn't be all that good. My 30" screened BBQ Grill with helix feed, after all, was barely up to the job. But for AO-51's V/US mode, I'd think it would be fine, offer a whole lot less wind resistance, and weigh a whole lot less too.
Since AO-51's 2.4 ghz antenna is linearly polarized, it probably doesn't matter whether the result is left-hand or right-hand polarized, so it doesn't matter that I forget which "hand" rule to use for figuring it out...
I've also heard that these panel antennas may have great numerical gain, but also have a lot of loss (cheap PC board materials), so maybe this isn't too good of an idea. What do you think?
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