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
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
|