Paul, G4MD, said
Subject thread is heading back towards my territory!
Same here - showing my age!
The silver EF50's were service issue valves - VR91 for the RAF, ARP12 for
the army. I suppose the navy must have had them as well, but I don't
recall
the designation....Red ones were the civilian issue.
I'm sure I recall my late father saying the H2S set had over 100 of them,
and it was unknown for them all to be working simultaneously!
I worked on H2S Radar when I was in the RAF but I can't remember there being
100 VR91s used. The equipment had a wide band 45MHz IF strip with about 8 or
9 red VR91s. Much sought after from the ex-govnt radio stores as home-brew
TV
receivers for receiving Alexander Palace.
H2S Mk 3G and H2S Mk4A were quite reliable considering their complexity. The
greatest cause of faults was the Pye plugs used for coaxial cable inter unit
connections.
The ARP12 is a directly heated pentode used in battery operated Army pack
sets.
The E88CC is a double triode frame grid valve that was used in UHF TV
tuners, designed to overcome the space charge effect at these frequencies.
They were used until superior solid state devices came along.
At the Amberley Museum we have 1000s of these valves!
Regards,
Peter, G3LDO
e-mail <[email protected]>
Web <http://web.ukonline.co.uk/g3ldo>
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