[amsat-bb] Cuscraft 416-TB and 22XB phasing harneses???

Bob WB4SON at gmail.com
Tue May 24 15:00:29 UTC 2016

Just another person's opinion on the following:

"I don't think it is worthwhile setting up the ability to switch from LHCP
to RHCP or vice versa if the spacecraft has linear antennae"

My personal experience says that if your goal is to maximize your
horizon-to-horizon communication, then you need the LHCP/RHCP switch.  When
doing an ARISS contact with the ISS, which uses a linear antenna, switching
polarity was the difference between a weak or non-existent signal and one
that was full quieting.  The ionosphere does strange things to a signal
(Faraday Rotation), that results in it taking on the characteristics of a
RHCP or LHCP signal at times.  If your antenna happens to be the opposite
at that moment, then you will experience a very deep fade due to the
mismatch in polarity.

Certainly working the ISS for a room full of kids is a different thing --
you want them to have the best possible experience and recognize that lay
people are not good at digging signals out of the noise.  Your requirements
for the best possible signal levels at all times is higher than during
casual communication.

If you are a horizon-to-horizon person trying to maximize your contact
success then the polarity switch will make sense.  Otherwise skip it as
Chris suggested.

73, Bob, WB4SON

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