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

Patrick STODDARD (WD9EWK/VA7EWK) amsat-bb at wd9ewk.net
Tue Mar 28 23:03:24 UTC 2017


Another option for diplexers as bandpass filters would be the MFJ
diplexers. I use an MFJ-916B diplexer for my satellite station,
and I saw a test comparing this with a Diamond MX-72 diplexer
that was done a little over a year ago:


Summary: the MFJ diplexer outperformed the Diamond unit. Also, the MFJ
diplexer costs about half of what you normally see for the equivalent
Diamond or Comet units. And the MFJ-916B is made in Taiwan, not


Twitter: @WD9EWK

On Tue, Mar 28, 2017 at 10:51 PM, Bob <WB4SON at gmail.com> wrote:

> 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
> _______________________________________________

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