Using subminiature tubes in a radio

[Findm-Keepm]

Originally Posted by wa2ise

I haven't seen any 12V heater subminis, though I have several with 26V heaters. Not sure, but maybe aircraft had 26V power.

Yep - 28VDC was the DC bus in Military aircraft, and I'd imagine some civilian aircraft as well. The AC bus(es) are 115VAC 400 cycle and 26V 400 cycle.

And yes, the military used TONS of subminis in Avionics - I worked on the ARN-52 Tacan receiver that used submini tubes in the RF/IF modules. They tended to go weak, never "bad" - and were all socketed.

Here's the innards of the ARN-21, it's predecessor:



Cheers,