[time-nuts] US Army Frequency Standard

[John Howell]

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.