[AMPS] K2RIW 432 Mhz Stripline Amplifier (Dec 72 QST)

[G0MJW]

The PSU is 2000-2500V at 500mA to 1A for the anode. The screen grid requires
a stiff supply at 350V that can source and sink 20mA per valve. Grids
are -55ish volts for a standing current of 100mA per valve. Several designs
fo supply boards exist, Downeast Microwave Tetrode boards (AKA G3SEK) will
do what you need.

I had a K2RIW chassis that I could never get to work - so beware. It was a
pretty accurate copy of the ARCOS design. K2RIWs can be/are difficult. If
yours has never worked, it may be better to forget it and go for a different
design using a triode, especially when you consider the PSU complexity. You
can buy an AM-8155 for less than it will cost you for the K2RIW PSU that
reportadly gives 400W on 432 MHz.

My chassis is now a 70MHz amplifier where it can rather easily produce the
160W required. It is easy to modify the chassis for bands from 50MHz through
144 MHz.

Mike


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