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GRR-24 Radio Receiver Set - A UHF Single Channel Radio Receiver set built by ITT Aerospace for air-ground communications. Put in place at USAF and RCAF heavy radar sites in the mid-1970s to replace similar radios that used vacuum tube technology. One component of the USAF Rivet Switch program.

GRR-24 Radio Receiver Rack Mounted at Mill Valley AFS, 1978.

GRR-24 Radio Receiver

From TO 31R2-2GRR-112: Receiver, Radio GRR-24(V) is a single channel solid-state superheterodyne receiver that operates in the amplitude modulation (AM) mode in the radio frequency (rf) range of 225.00 to 399.95 MHz. It is capable of reception in this frequency range on any one of 3500 channels spaced 50 kHz apart using the 50 kHz IF crystal filter or on any one of 7000 channels spaced 25 kHz apart using the 25 kHz IF crystal filter. The operating frequency is determined by either the oscillator crystal frequency selected or the dial setting of the oscillator synthesizer. An oscillator-synthesizer module is available which is directly interchangeable with and replaces the crystal oscillator module.

Compatible with the TSEC/KY-8, -28, AND -38 Speech Security Equipment when a wide bandwidth crystal filter is used.

GRR-24 Radio Receiver
Element Value Notes
Nomenclature GRR-24
Variants GRR-24(V)
Manufacturer ITT Aerospace
Introduced 1970s
Number Made
Type Single Channel Ground to Air Radio Receiver
Frequency 225-399.975
Number of Channels 3500 or 7,000
Channel Spacing 50 or 25 Khz
Primary Power 105-210, 120/250 Vac, 47-420 Hz
22-30 Vdc
Technology Solid State (Transistor)
MTBF 20,000 Hours
MTTR 15 Min
Dimensions 3-1/2 inches high; 19 inches wide; 12-1/4 inches deep (Standard 19-inch rack or cabinet mounting)
Weight 22 lbs

See Also:


  • Winkler, David F., Searching the Skies: the Legacy of the United States Cold War Defense Radar Program, USAF Hq Air Combat Command, 1997, 192 pages, Pdf
  • MIL-HDBK-162A, 15 Dec 1965.
  • TO 31R2-2GRR-112 - SERVICE AND CIRCUIT DIAGRAMS RADIO RECEIVER AN/GRR-23(V) AND AN/GRR-24(V), 1 Apr 1978 through change 18, 21 Apr 2012, Pdf


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