@M0KHR Nope, it has a 1B40 Argon-filled plasma tube with a 0.2 microcurie Cobalt-60 source. When it is in a strong RF field, the Co-60 and bias voltage cause a plasma to form, which shorts out the intermediate cavity between the 1 kW TX and the delicate crystal diode RX cavity. It can take 500+ watts, but only for a microsecond, at about 1000 pulses per second. Problem is that Co-60 half-life is only 5.3 years, so after a decade, it stops working, and by now, nowt left. https://lampes-et-tubes.info/mwtr/1B40.pdf