[amsat-bb] Re: eggbeater rx performance

[Art McBride]

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 at amsat.org [mailto:amsat-bb-bounces at 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
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