Motorola TLN6824A Vibrasender Tone Reed 173.8Hz CTCSS PL 6AUSED.
Need to add PL (Private Line) (aka CTCSS) to that old Motorola (MSR2000 vintage)
Used but tested
This is the gold standard in PL Decoders as far as its ability to decode a tone out of on-channel noise)
Designed by Bramco Corporation of Piqua Ohio for Motorola this is a contactless mini-reed
NO contacts to get dirty or burn. Inside there is a tiny on-legged tuning fork with a magnet mounted crosswise in the end of the tine . The magnet moves inside two tiny coils and forms a very precise and stable frequency resonant transformer. Go find a google copy of Bramco's 1966 tome "Control techniques with Resonant Reed Relays "
Temperature Stability: Frequency varies less than 0.002% per degree C
Impedance: approximately 1000 ohms at resonance (input and output)
(but different model numbers used impedances from 500 ohms to 5 K ohms).
Drive Level: 66-300 Hz - 0.05 to 0.2 VRMS
Drive Level: 300-3000 Hz - 0.10 to 0.3 VRMS
Encoder Freq. Tolerance +/- 0.3% (- 40 to 85 degrees C)