[Milsurplus] What is it?

[Robert Nickels]

On 6/23/2016 1:06 PM, Hubert Miller wrote:

> looks like free-running oscillator, which surprises me

Look again.  The crystal is missing but part of the socket can be seen 
in the top view between the motor and V301.

> And no modulator? How is the normal / abnormal condition signalled ?

On/Off keying, aka "CW", by the Cramer cam switch.   My guess is that when the alarm condition occurs, power would be applied to this device for a period of time,  allowing it to warm up and transmit it's carrier in the coded sequence enough times to assure it would be heard on the other end.   The receiver would have had a COR circuit connected to a counter or some kind of display device that would tell humans which transmitter generated the alarm.   My guess is that since there is no "condition" information the application was one in which just knowing there was a problem was sufficient.  In that regard it could have been a fire or burglary alarm, but those were typically done over phone lines that may not have been an option for a remote pumping station or something like it.

73, Bob W9RAN