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VHF Surveillance Receiver - this page is a stub

The R-744A was a general purpose valve-based VHF surveillance receiver, developed by the US Army Signal Corps in 1957/58 [A]. The receiver is suitable for AM, FM and CW signals and has a frequency range of 20 - 100 MHz. It was intended for intercepting enemy radio signals as well as for radio direction finding. The device is powered by a 24V DC source, such as the battery of a vehicle, backed up by internal LT and HT batteries. The complete set, consisting of the radio and various accessories, is known as OA-1451/PRR and also known as NSN 5821-00-082-3847.

Image of the complete R744 setup, taken from the manual [A].

The R-744A was manufactured under contract of the US Army Signal Corps by Arvin Industries and by P.R. Mallory Company, Inc. The radios were used for intercept and direction finding in Vietnam, Canada and Australia, and were produced in small quantities, which is why they are so rare and why there is virtually no information about them on the internet. The receiver was designed as a Surveillance Receiver and has the advantage of being continuously adjustable.

Furthermore, it was suitable for the reception of AM, FM and (modulated) CW, whereas most existing receivers were FM-only. The CIA used a slightly different receiver, the SRR-4, that was based on the same design. It covered 50-200 MHz and was also built in small quantities.

 More about the SRR-4

  • R-744A/PRR
    Basic model with bandspread knob. Manufactured by Arvin Industries in the US. Known serial numbers are 007, 12 and 16 [1].

  • R-744A
    Later model (without the '/PRR' suffix in the model number. Differences unknown. Known serial numbers are 22, 59 and 60 [1].

  • R-744(XE-3)/PRR
    Later model without bandspread knob. Manufactured by P. R. Mallory & Co. Inc. in the US.

  • SRR-4
    Special model for the CIA, with extended 50 - 200 MHz frequency range. In addition, it can be powered by 12V DC and from the 110V and 220V AC mains.
Optional parts
  • Batteries (A: BA-406/U and B: BA-418/U)
  • Directing Finder Antenna
  • VHF Antenna
  • Headset 600 ohm, e.g. HS-33
  • Vehicle Mounting Base MT-1988/PRR
  • Power supply unit PP-1481/PRR (internal)
  • Power cable (24V DC) CX-4377/U
  • Type
  • Frequency
    20 - 100 MHz
  • Modulation
    CW, MCW, AM, FM
  • Sensitivity
    AM < 1µV, CW < 0.3 µV, FM < 1µV
  • IF
    4.3 MHz
  • Bandwidth
    75 kHz ± 10 kHz at 6dB, < 270 kHz at 60dB
  • Calibration
    Built-in crystal calibrator with 2 MHz interval
  • Rejection
    IF ≥ 100dB, other 80dB (20-77 MHz), 70dB (77-100 MHz)
  • Power
    24V DC (or batteries)
  • Current
    LT: 450 mA (1.25 V), HT: 13.5 mA (40.5 V)
  • Batteries
    LT: BA-403/U, HT: BA-418/U
  • Vehicle PSU
    PP-1481 (XE-3)/PRR
  • Output
    5 mW at 1000 Hz into 600 Ω
  • Valves
  • Temperature
    -40 to +65 °C (Storage -60 to +70°C)
  • Altitude
    Sealevel to 3 km
  • Humidity
    ≤ 98%
  • Weight
    6.8 kg (8.5 kg with batteries)
  1. Instruction Book for VHF Receiver Group OA-1451/PRR 1
    US Army Signal Corps, 1958. Order number 994-PHILA-57.
    1958 (with errata sheet of 24 June 1958).

  2. TM 11-5825-203-10
    Operating Instructions (unavailable). 9 January 1961.

  3. TM 11-5825-203-20
    Organizational Maintenance Manual Receiver Group OA-1451/PRR
    Includes R-744B/PRR receiver. Department of the Army, 10 April 1961.

  4. TM 11-5825-203-20 changes C2 thru C6
    Headquarters Department of the Army. Latest change 29 August 1975.

  5. Raytheon. Subminiature tube (valve) type CK6611
    1 April 1957.

  6. Raytheon. Subminiature tube (valve) type CK6612
    1 April 1957.
  1. Superceeded by TM 11-5825-203-10 on 9 January 1961.

  1. Simon Boxton VK2UA, R-744 VHF Surveillance Receiver
    Visited April 2016.
Further information
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Crypto Museum. Created: Thursday 14 April 2016. Last changed: Wednesday, 14 October 2020 - 10:17 CET.
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