Eric, A Quadrifilar Helix antenna will meet your needs, and if you choose 1 wavelength, 1 turn design you will have a greater gain at the horizon than at the zenith which is what you need to compensate for the change in satellite distance to the observer over the entire pass. It is also circular giving excellent rejection to ground and building reflections that cause QSB. The designs were developed by C.C. Kilgus MSEE in the mid to late 60's. Designs vary from 1/4 Wave, 1/4 turn to 1 wave length, 1 turn. His work was published in the December 1970 Microwave Journal beginning on Pg 49.
Art, KC6UQH
-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Eric Fort Sent: Friday, May 29, 2009 6:17 PM To: Amsat BB Subject: [amsat-bb] eggbeater rx performance
I/m interested in the possibility of using oscars 27, 29, 50, 51, and 52 without using rotors or directional antennas and maybe while mobile. Uplink seems not to be a problem as one can always QRO to a level where the satellite sees an apropriate signal level that is enough but without robing power from other transponder users. On recieve though you still gotta be able to hear 'em to work 'em. Is an eggbeater and a preamp enough to hear decently or is there another (better) way? Is working mobile and/or without directional antennas even practical? what's the best way to do it?
Thanks,
Eric AF6EP _______________________________________________ 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
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