Dutch radio tube that won WW2
 

And interestingly enough, just a couple of years into the war the EF50 was also being used as the V5A, RF Driver and Buffer valve in the Wireless Set No. 19 Sender circuitry.

So, the next time you are looking in your 19-Set, or the bottom rack of its Spare Valves Box, take a moment to admire that bright red rectifier can smiling up at you.


David

Ef50
 

Yes I have noticed the EF50 tubes that were used in the 19 sets, a round red can that stands out among the glass octal tubes. .... I must look up and see what the 1943 Aust. AWA 19 set used in that application, AWA might not have had access to the EF50 in 1943.

Reading the long article, the author mentions the little RCA VHF acorn tubes , I didn't know they were first made as early as 1934
https://www.dos4ever.com/EF50/acorn1.pdf