STATION MONITOR - A39865
 

Thes A39865 was used as monitoring equipment for broadcasting stations. It provided continuous visual indication of the percentage modulation of the transmitter carrier and checked the frequency of the emitted wave by means independent from the transmitter
Frequency accuracy  was plus or minus 50 cycles.

FREQUENCY STANDARD

This unit has a carefully calibrated, temperature controlled, quartz crystal oscillator, operating at a very low power level. The output is then fed to circuits which produce a beat note between the oscillator and the transmitted carrier.

FREQUENCY DEVIATION METER

A galvanometer was used to indicate the deviation of the transmitter carrier frequency from that of the  requency standard oscillator within plus or minus 100 cycles. ThIs meter  is so. calibrated that when the station transmitter is exactly on it's assigned frequency, the reading is zero, Any
deviation in in the transmitted frequency will produce a note which will be registered on the meter as  "cycles high" or "cycles low".
 
 

station_monitor_100_1908_a39865.jpg
Image provided by Lewis Bodkin

Contributors and Credits:

1)  Lewis Bodkin  <05bodkin555(at)gmail,com>

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Feb 6/08