This looked interesting.
What was this used for? Let me know.
Some type of data received that drives a WD-1 wire pair plus has a 10-pin output connector.
It's a receiver that's powered by a BA-5590/U battery (and because of the CAUTION label I'd say specifically the BA-5590/U when it was made rather than a rechargeable battery). There's provision to power from either the battery or an external power source (Voltage TBD). There's also a choice of "A" or "B" receive frequencies (values TBD). The output connector is an MS3114 E12-10P (A, C & D: ground, B: output, other pins not used.
None of the four battery wires are shorted to another indicating two isolated power supplies. That may may indicate that the external power source is an A.C. voltage.
When the external power source is used it's positive terminal is connected to the chassis. There are a couple of TO-220 linear voltage regulator ICs: 7805BT (+5V) & 7806BT (+6V).
Under the battery hold down clamp is the antenna storage compartment. The telescoping antenna is one foot long.
A 48 in, or 1.2 meter wavelength corresponds to a frequency around (300/1.2 = ) 246 MHz which is in the military 225 to 399.99 MHz UHF band.
The date codes are both 1985 and 1986.
Possible Frequency Plan for one of the channels:
Signal input at 178.55 or 199.95 or 237.80 or 216.40. These are from N*37.85 MHz +&- 10.7 MHz.
First LO is a harmonic of 37.85 MHz resulting in a first IF of 10.7.
Second mixer LO of 10.245 results in a second IF of 455 kHz.
Fig 1
Fig 2
Fig 3
Fig 4 10.245 MHz crystal used in FM radios.
XC3362P IC might be an FM radio?
One of the channel select crystals is 37.85 MHz
Fig 5 External DC input (output?) field wire terminals.
68705F2CS micro controller with 3.2768 MHz xtal clock.
Binary divides to 100 Hz
Fig 6
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