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B7G battery valves for military use


B7G battery valves for military use

Post by Radiomobile » Sun Nov 04, 2012 11:16 am

I know that the B7G series of battery valves appeared in miniature radios in the USA around 1940/41 (eg the RCA Victor BP-10) and more generally from around 1947 in the UK.

I am interested in the military use of these valves, I know they appeared in the famous American walkie talkie the BC611 during the war but I wonder if they were ever used in British military equipment at this time?

I remember in the 1950s having the choice between buying a Mullard DF91 or a 'surplus' 1T4 for half the price. As 'surplus' B7G valves were available at that time did it mean they were surplus to UK military requirements?

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Re: B7G battery valves for military use

Post by Michael Watterson » Sun Nov 04, 2012 12:28 pm

WS 88 maybe one of the first UK Walkie/Talkies. Used a load of B7G valves.
A VHF band I channelised radio in an ammunition pouch and battery pack in 2nd pouch is post WWII though.

They made two covert receivers in UK for dropping behind the lines, a Polish designed superhet and the Norwegian designed 3 x 1T4 TRF/Regen, the Sweetheart that used the RCA B7G tubes.

I think problem was that all B7G would have had to be imported till about 1946 / 1947. Eventually by 1942 they were importing Sylvania and RCA Octal tubes and for battery tube use the Mazda octal and Edge connect production seems to have been gone by 1943. Apart from EF50, I think virtually all valve production was Octal in UK by 1943. I can't actually think of ANY UK made battery valve Military model during WWII, they used rotary converters (dynamotors) and vibrator packs with mains valves. There may have been SOMETHING that went on a backpack made by UK for Military during WWII, But I can't remember reading or seeing such a thing.

Of course in the 1950s to save space even mains military equipment used a lot of mains type B7G, not often seen in UK domestic models, but used in USA sets. My nearby radio friend has box loads of CVxxx and CVxxxx B7G types, mostly mains. Some are battery type and interestingly some are only US equivalents, not DF91 / DAF91 / DL92 / DL94 types. (1T4 / 1S5 / 3S4)

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