[CQ-Contest] Solid State Amp - An invitation

[VR2BrettGraham]

K6IF announced:

>For the last few weeks, I have been working on a project to design and build
>a 1500 watt solid state HF amplifier.  The impetus for this project is the
>need, in a modern SO2R contest station, for some way to automate amplifier
>tuning without spending $12k on a pair of Alpha's or Acoms.
>
>My dream is not simply to build such a beast, but to create an "open source"
>style collaborative project.  Because a project like this breaks down into a
>few fairly independent parts (RF section, output filters, control circuitry,
>etc.) - it should be possible for a group of us to work on it together.  In
>the end, we could create a set of designs, PC boards, part lists, firmware,
>etc. that would make it possible for any contester who was interested in
>building such an amp to do so relatively easily.
>
>I have been in contact with, and received lots of input and advice from,
>several folks who are either working on similar projects, or in a few cases
>have actually built such an amplifier.  Their assistance has been
>invaluable.  I have gathered what I have learned onto a web site,
>http://www.k6if.com/ssamp/ .
>
>If you have any interest in a project like this, I would welcome your
>comments, thoughts, suggestions, or (best of all) active involvement.  There
>is a discussion forum that we can use on the site.

I have always wanted to use my solid-state amp with a transfer relay,
so I can do SO2R with one amp.  With relay switching of the output
LPFs, a solid-state amp could bandswitch as easily as it does
between transmit & receive.  Based on my using a solid-state amp
for RTTY contesting, the increased duty cycle shouldn't be a problem.
With a pair of K2s, one could fit a complete SO2R kW station into a
single suitcase that doesn't exceed one's weight allowance.

But those LPFs are one of the problems with solid-state amps - they
are wide open at frequencies below the band of operation.  I have
though of trying BPFs like the Alpha 374 or whichever one it is with
"bandpass" tank circuit settings.

I have two ex-PLA surplus 1kW+ solid-state amps still in storage
waiting for a reason to do something with them... the timing of Dan's
post is handy as I'm beginning to get annoyed at having to retune
the GU74B when I switch between antennas - even if one is flat &
the other has not much higher SWR than that.

73, VR2BrettGraham