[amsat-bb] 432 MHz dish feeds for EME use

["K7XQ" <k7xq@xxxxxxxxx>]

I see that a typical 432 MHz dish feed is a dual dipole over a reflector
/ backplane arrangement ( this is called the EIA feed ??? ). Also, most
432 MHz EME operations are linear polarized ( why is this so if there is
always a problem of faraday lockout, why not go circular to eliminate
this problem ??? ).

Questions: 

If there are only two diploes used for the feed, are they both at the
same polarization or at right angles to each other to achieve switchable
polarization ???

I have seen on the web a design that utilizes a full wave 25.5 inch loop
over a reflector / backplane arrangement, how does is compare to the
dual dipole design ???

What is the f/d dish limits for these feeds ???


K7XQ   Jeff   Atwater, CA.
Grid: CM97qi
EME, Satellites, Meteor Scatter
JT-44, FSK441 ( WSJT ) , CW

144 MHz: 2 X 2MPX20's H/V 16 dBd & 2 X 2M12 3 W.L.  H only 15 dBd 800
Watts single 3CX800A7
( looking for two more 2MPX20's to make four total )
Initials: 61

432 MHz: 4.3 meter dish 21 dBd 800 Watts 2 X 4CX400A7
Initials: 5

1296 MHz: 4.3 meter dish 30.5 dBd 150 Watts 2 X 2C39 water-cooled ( soon
400 Watts single GS15B  )
Minimum dish elevation of 20 degrees 
Initials: 22

10348 MHz: 4.3 meter dish
Project for 2004 !
Initials: 0


K7XQ Homepage: http://www.elite.net/~k7xq/k7xq.html

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