[Milsurplus] 211 Tube Note

[Mike Feher]

Hue -

There were a lot of tubes prior to the 211 series that eventually became the
211 series. Besides the early Navy CG type 50 watt tubes the common 50 watt
tube was the 203A which eventually developed into the 211 series and later,
during WWII known as the VT4C. There were numerous designators after the 211
for slightly different characteristics, and to the best of my recollection
was the 211E which actually had "RF chokes" built into the tube itself to
prevent high frequency parasitic oscillations and were more intended for
audio use. While I do not have the advantage of seeing the reference you are
citing, either you misread it, or, it is in error. There are no combinations
of any total currents that add up to 7.5 amps. The filament as I recall is
around 3 or 4 amps at 10 volts. Plate current is typically around 200 ma at
about 1 KV. If what you read is indeed what is printed, you have a real rare
manual. 73 - Mike 

 
 
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
 
 
-----Original Message-----
From: milsurplus-bounces at mailman.qth.net
[mailto:milsurplus-bounces at mailman.qth.net] On Behalf Of Hue Miller
Sent: Saturday, March 22, 2008 5:15 PM
To: milsurplus at mailman.qth.net
Subject: [Milsurplus] 211 Tube Note

>From RCA booklet "Radiotron UV-211" dated Jan. 1932:

"Radiotron UV-211 is not recommended for use at 
frequencies greater than 3000 kilocycles. There are 
other types of Radiotrons especially designed for use
at hgher frequencies. In any case, the radio frequency
grid and plate currents of the UV-211 Radiotron must
never exceed 7.5 amperes."

No other explanation! However, i'm sure the grid would
not stand 7.5 amps!  -Hue Miller
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