[amsat-bb] TUning the antennas on a Cubesat

[Robert Bruninga]

Someone asked me how to tune the antennas on a cubesat without the
instrumentation totally becoming part of the antenna system itself?



I said you have to put the SWR instrument inside the cubesat as we did
here:   http://aprs.org/PSAT2/SWR-testing-0160x.jpg



But that only works on a 1.5U cubesat where and MFJ Antenna Analyzer will
fit!



The other method is to just put in a bidirectional coupler chip, and then
feed the forward and reflected voltage taps to the internal cubesat
telemetry system and then compute the SWR from these two Forward and
Reflected power telemetry channels.



Bob, WB4APR