[time-nuts] US Army Frequency Standard

John Howell j at howell61.f9.co.uk
Tue Jan 24 21:45:21 EST 2012


Thank you everyone for your comments, and if I've got it right Brooke, if you paste this into your browser:   

http://www.flickr.com//photos/75ohm/sets/72157629019710615/show/

you should get a quick tour and a movie!

This is indeed a tuning fork driving a synchronous motor that has a perforated disc on its shaft. The whole unit operates as it should and the quality of manufacture is superb, so I'm reluctant to pull it apart  but I am curious as to the type of photocell it uses. It seems very small and the dates on many of the components suggest manufacture in the mid to late 1950s so what was around to do the job at that time? There is no cathode bias on the "voltage amplifier" that it feeds which suggests it s Photovoltaic rather than Photoconductive.

Thanks again for your replies,

John H.


On 24 Jan 2012, at 22:34, Brooke Clarke wrote:

> Hi John:
> 
> Is there a photo of the freq std on line?
> 
> Have Fun,
> 
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/Brooke4Congress.html
> 
> 
> John Howell wrote:
>> Thanks Bob,
>> 
>> If it helps the switched frequencies are: 0, 10, 20, 40, 60, 80, 100, 120, 140, 160, 180, 190Hz.
>> 
>> John.
>> 
>> On 24 Jan 2012, at 22:09, Bob Camp wrote:
>> 
>>> Hi
>>> 
>>> Sounds about right for calibrating / verifying vibrating reed frequency
>>> readouts.
>>> 
>>> Bob
>>> 
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
>>> Behalf Of John Howell
>>> Sent: Tuesday, January 24, 2012 5:00 PM
>>> To: Discussion of precise time and frequency measurement
>>> Subject: [time-nuts] US Army Frequency Standard
>>> 
>>> Hi All,
>>> 
>>> I recently obtained a curious Low Frequency Standard dating from the late
>>> 1950s. Its output can be switched to a number of frequencies from 10 to
>>> 190Hz, derived from a tuning fork. It is marked "Signal Corps" and "US Army"
>>> with a type number TS-65D/FMQ-1.
>>> 
>>> 
>>> Does anyone have any information about this unit, in particular what it was
>>> used for and why the strange negative going pulse output and specific
>>> frequencies.
>>> 
>>> Thanks in advance,
>>> John H.
>>> 
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