[amsat-bb] Filter out 3rd harmonic of 145MHz

[Bob]

I actually dug up a Comet CF-4160J Diplexer (both Comet and Diamond call
them "Duplexers") and swept its response with my Spectrum Analyzer, using
the Low-Frequency and Common Port. I was also curious to find out if it
mattered if the High-Frequency Port was terminated or not.

The bottom line is that this particular Diplexer would reduce the 2-meter
3rd harmonic by 55 dB, and had an insertion loss of 0.12 dB.  And I
confirmed that there was a small reduction performance if the
High-Frequency Port was not terminated.

I would expect the performance of Diamond models would be similar and I
will test one when I find one.

The actual report can be found here:  http://wb4son.com/wpblog/?p=2828  (if
the link is blocked, try WB4SON dot com and search for CF4160)

73, Bob, WB4SON