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VHF/UHF Surveillance Radio Receiver - wanted item

SRR-5 is a solid-state VHF surveillance radio receiver, designed around 1960 by the Technical Services Division (TSD) 1 of the US Central Intelligence Agency (CIA) as the successor to the valve-based SRR-4. It was developed and manufactured at Radio Receptor Company Inc. (RR) in New York (USA). It covers all frequencies between 50 and 400 MHz and can demodulate AM, FM, CW and modulated CW signals. Although it was a general communications receiver, it was typically used for clandestine operations, in particular for the reception of covert listening devices (bugs).

The receiver measures 30.5 x 27.5 x 10.8 cm and weights just under 9 kg. It can be powered by internal batteries or by the 88-264V AC mains. It features two separate tuners: one for the 50-200 MHz range and one for the 200-400 MHz range, known as the LOW and HI bands.

The desired band is selected with the BAND-switch and each tuner has its own antenna input at the front panel. For short-range reception, the supplied telescopic antenna, mounted at the top right, can be used. Alternatively, an external VHF or UHF antenna, or a car antenna can be used.

Although it is not recognised as such, the SRR-5 is featured in H. Keith Melton's excellent book Ultimate Spy [1], where it is appropriately described as a listening post receiver. Although the SRR-5 was commonly supplied with a black front panel, the one in the book has a white front panel and a blue case shell. The SRR-5 was produced in limited quantities from the early to the mid-1960s by Radio Receptor Company Inc. in New York [4]. It was commercially available to approved customers (e.g. law enforcement) only, and was later complemented by the SRR-8.

  1. The Technical Services Division (TSD) of the CIA was renamed Office of Technical Service (OTS) in 1974 [2].


  • LOW
    49-204 MHz
  • HI
    204-404 MHz
The following accessories are currently known:

Operating instructions and full service manual
Although Crypto Museum does not have an SRR-5 receiver in its collection, we do have access to its technical manual and som eof its test sheets, which are available for download below [A].

The manual consists of a global description of the device, a description of its operation, a technical description of each sub-circuit, a block diagram, and full circuit diagrams.

 Download the technical manual

SRR-5 Technical Manual
Block diagram
Below is the simplified block diagram of the SRR-5 receiver. At the left are the two independent tuners: one for the LOW band (50-200 MHz) and one for the HI band (200-400 MHz). For each tuner, the frequency of the local oscillator (LO) is 16.5 MHz higher than the received signal.

The model number SRR-5 should not be confused with the AN/SRR-5, which is a radiation monitor used by the US Navy. Please note that AN/SRR-5 is a military designator, whilst 'SRR-5' is a typical CIA designator. The two devices are in no way related.
  • Device
    Surveillance receiver
  • Purpose
    Interception, monitoring, reception of bugs
  • Model
  • Design
    TSD (CIA)
  • Manufacturer
    Radio Receptor Co. Inc., New York (USA)
  • Predecessor
  • Successor
  • Frequency
    49-204 MHz
  • Bands
    2 (see below)
  • Modulation
    AM, FM, CW, MCW
  • Dimensions
    305 × 275 × 108 mm
  • Weight
    9 kg
  1. 49-204 MHz
  2. 204-404 MHz
  1. Operation and Service Instruction Book, Radio Receiver SRR-5
    Includes full circuit diagrams and parts list. Date unknown.

  2. SRR-5 System Test Procedure
    Date unknown. 16 pages.

  3. SRR-5 Data Sheet
    Measurement report for individual SRR-5 receiver. Date unknown. 5 pages.
  1. H. Keith Melton, Ultimate Spy
    First edition 1996. Edition 2015. ISBN 978-0-2411-8991-7. p. 118. 1

  2. Wikipedia, Central Intelligence Agency Directorate of Science & Technology
    Retrieved December 2015.

  3. Pete McCollum, Personal correspondence
    September 2018.

  4. CIA, Trip report, Radio Receptor Co., Advanced Development Laboratory 2
    DC/TSD/APB, 28 October 1960.
  1. Image reproduced here by kind permission from Keith Melton, November 2017.
  2. Declassified in part and approved for release 5 December 2014: CIA-RDP78-03153A000700020015-9.
    Although the name of the company is redacted in the document, it is present in the original CIA file title [3].

Further information
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Crypto Museum. Created: Friday 25 November 2016. Last changed: Monday, 15 July 2024 - 08:24 CET.
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