I'm looking at an AN/SRT4A transmitter I've been sitting on for some time. The filament transformer, Kenyon S-11751 , is rated 70 volts 83 cycles. I put it on a Variac, it runs fine on 60 cycles, and this project just got a whole lot easier. Hallelujah! Maybe I need a shed on rollers to simulate sea motion... Richard, AA1P