[Milsurplus] Subminiature Tube Video.. More

[J Forster]

Last spring, there was a discussion of people still making vacuum tubes.

A few years ago, Norm Krim, the pre-WW II developer of the Raytheon line
of sub miniature tubes, gave me a copy of a video made, by the MIT
Industrial Liaison Office,
just before the last production line for those tubes in Quincy,
Massachusetts, closed down.  With many thanks to Debbie Douglas, Curator
of Science and Technology at the
There were a number of replies after the post below, including:

====

Subject:  RE: [TekScopes2] Subminiature Tube Video
   Date:  Mon, 30 Jun 2008 12:56:34 -0700
   From:  george.h.patrick at tektronix.com
 Reply-To: 

Most likely used for KW37s.  A KWR37 receiver used around 500 submin
tubes, and there was at least two of them (and usually more) on every
ship and shore station in the Navy.  Transmitters (which used roughly
1600 of the little buggers) were located at every communications and
intelligence site on shore.  These were still in use in 1980 when I got
out of the Navy, and I have heard they were finally retired in the
1990s.

George Patrick
Tektronix, Inc.
Central Engineering, EDS Applications Support

====

On following this lead, I found Jerry Proc's most interesting site:

http://www.jproc.ca/crypto/kwr37.html

Best,
-John

===================


MIT Museum,  that video is now available for viewing on MIT's Tech TV:

http://techtv.mit.edu/file/1125/

Note that there are two options that appear below the picture on that
page. Windows users might want to select the Flash Video option. I know
that works as two friends
have been able to view it successfully. You will likely need a broad
band connection. The film is about 16 minutes long.

Norm has told me that the tubes were originally developed for hearing
aid use pre-WW II, and were improved for use in the Proximity Fuze
during the war. Just imagine, a
vacuum tube that can be fired from a large gun and still operate. One
clever trick to help the tubes survive was that the filaments were not
powered until the shell was
in free flight, either by addend a small wind turbine generator on the
nose of the shell, or by having the battery void of electrolyte until
the shock of firing and the
spin of the shell filled the battery.

Shells using the Proximity Fuze were successfully used in the Battle of
the Bulge (they caused the shells to air burst, increasing their
effective area) and together with
the SCR-584 Radar against the V-1 "Buzz Bombs"

Note that the tubes being produced in the video are not actually for the
Proximity Fuze, but were for some US Navy Crypto application.

There is at least one book about the Proximity Fuze ("The Deadly Fuze")
and there was also a PBS Nova program of the same name.

I hop you enjoy the film.

Best,
-John

(c)