[amsat-bb] Preamps and Polarization Switches

Fred Castello fredcastello at gmail.com
Fri Jul 1 22:13:19 UTC 2016


Newbie here and I am trying to put together a station.  I have a question about preamps.  I am making the following assumptions but please correct me or outline your station feeds if I am incorrect in my assumptions:

Most experienced operators are using moderate to high gain yagi antennas, circular polarized.  I am thinking of purchasing the M2 LEO pack.  I am assuming that most folks are using RF protected preamps to keep from blowing them up on transmit.  It would be easier if one knew that they were always going to transmit on 2 meters (for instance) and one could place the NON RF protected preamp on 70 cms.  However, since there is a mix of V/U and U/V birds, it would seem the only way to get preamps up at the antenna where they belong is to use RF protected preamps ( with weather and RF protection, significantly more expensive).  Is there a role for diplexers here rather than running expensive RF protected switching?  Also, I know from my listening on my Elk Antenna that change in polarization can make a pretty significant difference in adequate reception.  So, it would also seem that there is a need with these type of antennas (M2 LEO) to have a polarization switching (cost for both antennas almost matches the original cost of the antennas).  Do most operators have these switchable polarization switches.  My shack is about 60 feet from the top of the roof, so I will have to deal with those losses in spite of using good cable.  I was thinking of just starting with the antennas (no preamps, no polarization switching) and see how things go.  Any thoughts or advice would be much appreciated.
Best
Fred Castello, KF4FC


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