Let's see, Boeing has to tell PECO when they fire up their MW wind tunnel, I don't think you'll find many DIY running such things as that.I have some DH Pentodes. 450W CCS anode rating. 120W g2 rating and a 10W g1. I am planning on a PP amp for ~300W output and still single-pair, Class A. No cooling fans needed. The glass is reated to 660 F.
they make an 833A look medium sized. The anode cap is 6SN7 sized. figure a PS for the PP amp to deliver 700 mA at 1k2Volts for the finals and drivers. G2 will be significantly lower, and run from its own supply.
regards,
Douglas