At Dayton 2002 I picked up a homebrew 8874 amp for 432 MHz. It appears to
be a reasonably well built copy of the K1FO amp which was in the October
1979 QST and several of the ARRL Handbooks from the early 80s.
The amp was apparently built with the wrong grid collet assembly. (Perhaps
the builder used what he had, in the best ham tradition.) The amp exhibits
some operational problems as documented in K1FO's followup article in the
July 1987 QST, which are traced to the grid collet.
My question is, where can one buy Eimac grid collets and other accessories
related to power tubes? The Eimac web site seems to want you to go to
Richardson Electronics, however Richardson's on-line catalog shows nothing
resembling the part number which I need.
I am looking for the Eimac 720359 collet assembly, either that or the
882931 grid collet flange. These same part numbers show up in the K1FO
3CX800A7 amp designs in the ARRL UHF/Microwave Projects manual, so I would
*hope* they are still available.
Say what you want about the Russian power tubes, but I for one think that a
design which allows the tube's grid flange to be bolted straight to the
chassis (without a bunch of fancy hardware) is pretty cool. I guess the
3CX1200Z7 is the same in this regard, but for a lot more $$$.
Thanks for the help.
73,
Dave/K8CC
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