[Amps] Johnson Thunderbolt questions

[peter.chadwick at Zarlink.Com]

Don't know about the Thunderbolt specifically, but my experience with the
4-400 and  4-250 family is that 2 to 2.5kV isn't really enough to get more
than about 400 to 500 watts PEP out in AB1. Both tubes have the same
filament, and thus the same peak current capability, as well as the same
screen dissipation: Cin and Cgp are the same, so the difference between
them is just the plate dissipation. I've never yet got out of one of them
the 425 watts claimed in the ARRL handbook tube data at 2500volts on the
plate. At about 3600 though, they go very nicely.......

73

Peter G3RZP