Dave G3WCB said:

Hi, Scott.

If you're into Big Bad Amps, you should check out G4FTC's site
http://www.qsl.net/g4ftc/amplifiers/136khz/home.htm He describes a 3kW LF
amp. that uses 8 x IRFP450's in a bridge arrangement. Biggest PA I've seen
so far!

The LF Experimenters Source Book (second edition, now out of print),
forerunner of The Low Frequency Experimenters Handbook, describes a 3kW
transmitter using a QY5-3000A tube in class AB1 with a plate voltage of 4kV.
This design by Tony Preedy, G3LNP used hardware from a salvaged Band II TV
transmitter. The limiting factor was the power available from a single phase
240VAC supply via a 13 amp socket!

Peter G3LDO