[amsat-bb] Pre-Amp Help

David Mennerich david.n2teb at gmail.com
Mon Oct 3 22:10:37 UTC 2016

I recently purchased an Advanced Receiver Research 2M pre-amp to use when
operating on the LEO SSB satellites.  I purchased the SP144VDG (24 db gain,
<1 NF).  They don't offer the lower gain, higher noise figure 2M pre-amps

I tried setting it up this weekend and when the pre-amp is on and I'm
transmitting on the 70cm band, I'm getting a lot of audio distortion.  When
I tried this during a pass, my audio on 2M was barely readable because it
was so distorted, but with the pre-amp off, I sounded fine.

I'm currently using a 2m/70cm Arrow antenna mounted on a portable Yaesu
G5500 Az/El setup.  When I spoke with ARR, they suggested it was a
desensitizing situation and it may be due to the 2M and 70CM antennas being
so close to one another.

Can anyone help or suggest some things I could try to eliminate this
situation?  Separate antennas?  Some kind of filter before the pre-amp?
The pre-amp sounds great when turned on, but right now it can't be used
when I'm transmitting at the same time on 70cm, which doesn't help.

Dave N2TEB

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