AN/FRR-60 Diversity Receiving System

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Just getting started on this page - more to come - I am currently restoring one of these systems

Usually in dual-diversity configuration - coupled with AN/FGC-60 FSK converter system, this makes up AN/FRR-73.

Manufactured by TMC - See K4OZY's DDR-5 web page
AN/FRR-60(V)	TMC DDR-5(V)
AN/FRR-60(V)1	TMC DDR-5A-5D/5D
AN/FRR-60(V)2	TMC DDR-5A
AN/FRR-60(V)3	TMC DDR-5B
AN/FRR-60(V)4	TMC DDR-5B3
AN/FRR-72	TMC DDR-5C/MSGA-1/ARCA-1
AN/FRR-73	TMC DDR-5A/MSGA-1
AN/FRR-74	TMC DDR-5K

Frequency synthesized in 100 cps steps from 2-32 mc . Each receiver section has 2 independent outputs.
One version has "Technimatic" remote control.

Synthesizer provides 1 part in 10^8 per day stability over 15 degrees C
- Synthesizer operates from 1mc master oscillator
- MC selector switch selects (using crystal filters) 1 of 31 harmonics of 1mc master oscillator as HF mixer signal
- Master oscillator is divided down by phantastron decade dividers to 100kc, 10kc, 1kc, 100cps reference signals
- Reference signals go to blocking oscillators producing rich harmonics
- Appropriate harmonics are selected by 4 decade switches each selecting 1 of 10 crystal filters
- All selected harmonics are mixed together to create 4.25 to 3.25 mc synthesized frequency (in 100cps steps)
Tuner supplies 3.75-33.75 mc HF oscillator (HFO) signal to Synthesizer.
- Synthesizer mixes selected harmonic of 1mc master oscillator with Tuner HFO to yield 4.25-3.25 mc
- Phase comparator compares Tuner's 4.25-3.25 mc signal with Synthesizer's 4.25-3.25 mc signal
- DC correction voltage is fed back to varicaps in Tuner's HFO to lock it to Synthesizer - Voila!
Some systems have 2 synthesizers, one for each receiver
Other systems have a single synthesizer for 2 receivers
- they can be operated independently but only one would have the high stability
With AFC enabled, audio output will remain within 1cps in SSB mode by locking to suppressed carrier

photo from TMC vintage radio web site

Each receiver section has:

NAVCOMMSTA Guam - 1960's