I'm hoping it's not too off-topic, but can anyone explain to me or have schematics of how the PC86 and PC88 (or their US and 6V heater equivalents) were used as RF amplifiers? I recently acquired a few and although I know a bit about tubes (been lurking here for a while and am finishing a degree in EE), I can't seem to find nor figure out how precisely they were wired up.
Datasheets say they were used as grounded grid amplifiers, by which I assume they mean with the signal applied to the cathode and with a plate and cathode resistor. I'd then assume a large cathode resistor and a small plate resistor, as this gives an input impedance of 1/gm or about 70 Ohms, decently matched to a 75 Ohm antenna (won't achieve a gain of mu anymore, though). However, I don't quite see how to make best use of the multiple pins per element, nor how they made a mixer rather than an amp out of these things.
Anyone with some experience in these matters?
Jw
Datasheets say they were used as grounded grid amplifiers, by which I assume they mean with the signal applied to the cathode and with a plate and cathode resistor. I'd then assume a large cathode resistor and a small plate resistor, as this gives an input impedance of 1/gm or about 70 Ohms, decently matched to a 75 Ohm antenna (won't achieve a gain of mu anymore, though). However, I don't quite see how to make best use of the multiple pins per element, nor how they made a mixer rather than an amp out of these things.
Anyone with some experience in these matters?
Jw