The military used them at UHF in cavities.
You could also look at the various 4CX250 VHF/UHF Handbook and magazine amps
for circuits. Then adjust RF circuitry for the different values of the 8122.
The 4CX250 series screen ring capacitor, Johnson 124-113, fits the 8122. The
8122 uses the same socket as the 8873, 8874, 8875, 3CX800 and is readily
available from several amp manufacturers.
The 8122 has a very fragile screen. Use protective circuitry and keep the
voltage at no more than 350 with a 2500V Ep. A Es of 300 is fine with a 2000
The Johnson 6 and 2 Thunderbolt uses 4X150's and is a decent circuit to copy
for a 2 band amp. The manual is on BAMA.
Ive used the 8122 for over 40 years and it is a good tube as long as care is
taken to protect it.
National Radio 1963-69
Member NCL-2000 Design Team
----- Original Message -----
From: "sulai je" <firstname.lastname@example.org>
Sent: Tuesday, August 14, 2007 6:03 AM
Subject: [Amps] Project for 8122 tubes
> I had some RCA 8122 tubes in my junk box since long time. Thinking to use
> them in a homebrew project so I start to search for an amplifier project!
> Either to UHF or VHF . HF Googling the net yields a zero project for those
> if any on can help with schematic and more info I will be appreciated in
> advance .
> 73s de 7z1sj Sulaiman
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