[Milsurplus] RadioSonde

[Al Klase]

Hi Hue,

Sounds like one I have here, except it's a 3A4 and the xtal
is on 3135.  It's part of a marvelous device called an
AN/AMT-3E.  This thing contains a motor and gear train that
turn a small "phonograph record" that has a 90-degree raised
sector.  Each grove on the sector contains a separate
two-letter group in Morse.  The disk rotates under three
arms actuated by the mechanical temperature, pressure, and
relative humidity sensors.  Somehow the signals from the
arms close a relay that keys the TX.  The best part is that
the disk mechanism make an audible buzz in morse even
without a B battery for the TX.

Each unit come with a separate calibration chart.  Mine is
dated 5-7-54. Device was built by Standard Coil Products
Inc.

Some college friends and I bought a pile of these for a
dollar apiece in about 1966.  We intended to pas these along
to fellow student as "hi tech" toys for 2 or 3 bucks. 
Unfortunately, we grossly over estimated the curiousity of
engineering students.  There may still be some stashed away
in the ceiling of the photo lab at Drexel.

I happened on to one of these a couple years ago.  I think
I'll have to get it going.

Al

Hue Miller wrote:
> 
> Which reminds me: if you were around in the 1960s (way back then), do you
> recall those
> "radiosonde" transmitter chassis at the surplus joint, the ones with a 3295
> xtal and a
> small flat bakelite piece as chassis, a 3A5 tube, and a few other parts
> including an
> rf choke of looked like 1-2 mH. There was NO tuned circuit, the rf choke was
> the
> plate circuit.
-- 
Al Klase - N3FRQ
skywaves@bw.webex.net
Flemington, NJ 08822
Web Page:  http://www.webex.net/~skywaves/home.htm