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Automatic CIA agent radio set

AS-3, 1 was an American modular solid-state automatic clandestine radio station, also known as a spy radio set, developed around 1959 on behalf of the US Central Intelligence Agency (CIA). From 1962 onwards, it replaced earlier valve-based radio sets like the RS-1 and RS-6 [1][2].

Some of the parts of the AS-3 radio station

A typical AS-3 station consisted of an AT-3 transmitter, an RR/E-11 or RR/D-11 receiver, a battery pack or PSU, and a burst encoder with tape cartridges. According to an early version of the manual, it was possible to connect a printer that was suitable for HELL transmissions [u].

  1. AS = Automatic Station (as opposed to RS = Radio Station).

AT-3 transmitter
Single-band receiver
Double-band receiver
Battery pack BP-3
AC Power Supply Unit AP-3
Text printer (HELL)
Burst encoder CO-3
Magnetic tape cartridge CA-3
Transmitter   AT-3
The AT-3 transmitter is the central piece of the AS-3 spy radio set. It measures 26 x 22 x 6 cm and weights approx. 3.5 kg. It is powered by a 12DC source (10A), and produces 25W output.

At the top right is a hinged lid below which is a bay for a CA-3 tape cartridge. It allows a pre-recorded message to be played back at 300 words per minute. At the right side is a socket for the RR/E-11 or RR/D-11 receiver. At the left is a socket for a TP-3 HELL printer.

 More information

Original AT-3 transmitter. Source unknown. Photograph obtained via Louis Meulstee [3].

Receiver   RR/E-11
RR/E-11 was among the first solid-state spy receivers developed by the CIA Radio Lab. It was intended for use as part of the AS-3 radio set, and could be plugged into the right side of the AT-3 transmitter, in which case power (12V) and antenna signal were supplied by the transmitter.

The receiver, which was released well before the AS-3 radio station was ready, could also be used stand-alone, in which case it could be powered by a 6V or 12V DC source, whilst antenna and headphones were connected directly to the unit.

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RR/E-11 receiver

Two-band receiver   RR/D-11
RR/D-11 was a plug-in receiver for the AS-3 radio station, that was similar to the RR/E-11 shown above, albeit with two frequency bands instead of one. The receiver is approx. 2.5 cm (one inch) deeper than the RR/E-11, but can be plugged into the same socket of the transmitter.

At present, no image of the two-band RR/D-11 receiver is available.

Battery pack   BP-3
For portable and mobile operation, the AT-3 could be powered by a purpose-built battery pack, designated BP-3, which plugged into the 9-pin male receptacle at the rear centre. It delivered a voltage of 12V DC at 10A.

At present, no image of the original BP-3 battery pack is available, but it is likely that it had the same width and hight as the transmitter. The depth is currently unknown.

AC power supply unit   AP-3
According to the original documentation, an external power supply unit (PSU) was available for powering the transmitter directly from the mains (110 - 240V AC).

At present, no image of the AP-3 power supply unit is available.

Printer   TP-3
TP-3 was a tape printer that could be inserted into the left side of the AT-3 transmitter. It allowed Hellschreiber signals from the RR/E-11 or RR/D-11 receiver (connected at the right side of the transmitter) to be printed on a paper strip.

It is currently unknown what the TP-3 printer looked like, and it is uncertain whether there are any surviving pictures of it. If you have additional information, please let us know.

 More information

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Burst encoder   CO-3
The AS-3 radio set was probably the second US spy radio set to use high-speed morse burst transmissions to reduce the chance of detection and discovery by radio direction finding (RDF). The first one was the RS-1 which it replaced.

The CO-3 was a simple device that allowed the bare morse elements – dots and dashes – to be recorded onto a CA-3 tape cartridge. Once recorded, the tape was played back on the built-in keyer of the AT-3 transmitter.

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CA-3 cartridge installed in CO-3 coder

Tape cartridge   CA-3
Messages – generally encrypted or otherwise coded – were pre-recorded with the CO-3 coder shown above, onto a CA-3 tape cartridge as shown in the image on the right. The cartridge contains regular magnetic audio tape of the era, and can hold up to 150 five-character words.

Recording a message was time-consuming, as each dot, dash and space had to be entered separately. But once it was recorded, it could be sent in a matter of seconds, which significantly reduced the chance of discovery by means of radio direction finding (RDF).

CA-3B Tape Cartridge

Development of the AS-3 started in 1956 and was finished in 1959 or 1960. A total of 150 receivers (RR/D-11 and RR/E-11) were procured for delivery in May 1959, and the final report was delivered in July 1959. Production of the AT-3 transmitter was halted however, but in August 1960, 10 prototypes were available, with an anticipated production run of 250 units [w].

Transmitter   AT-3
  • Frequency
    3 - 30 MHz
  • Output
  • Supply
    12V DC / 10A
  • Dimensions
    26 × 22 × 6 cm
  • Weight
    3.5 kg
Receiver   RR/E-11
  • Bands
  • Frequency
    3 - 12 MHz
  • Dimensions
    22 × 11 × 4 cm
  • Weight
    1.9 kg
Receiver   RR/D-11
  • Bands
  • Frequency
    3 - 12 MHz & 12 - 30 MHz
  • Dimensions
    22 × 13.5 × 4 cm
  • Weight
    1.9 kg
  1. Development of AS-3 Portable Radio Station, Progress Report No. 1
    1 October 1956. 1

  2. Development of AS-3 Portable Radio Station, Progress Report No. 2
    1 November 1956. 1

  3. Development of the Semi-Automatic Two-Way Radio Station AS-3, Progress Report No. 3
    1 January 1957. 1

  4. Development of the Semi-Automatic Two-Way Radio Station AS-3, Progress Report No. 4
    11 March 1957. 1

  5. Development of the Semi-Automatic Two-Way Radio Station AS-3, Progress Report No. 5
    1 May 1957. 1

  6. Development of the Semi-Automatic Two-Way Radio Station AS-3, Progress Report No. 6
    1 July 1957. 1

  7. Development of the Semi-Automatic Two-Way Radio Station AS-3, Progress Report No. 8
    1 November 1957. 1

  8. Contract RD-122, Task Order 1 - AS-3
    15 November 1956. 1

  9. Contract RD-122, Task Order 1 - AS-3
    18 December 1956. 1

  10. Contract RD-122, Task Order 1 - AS-3
    7 February 1957. 1

  11. Contract RD-122, Task 1 - AS-3 - Trip Report
    18 March 1957. 1

  12. AS-3 Contract RD-122 - Trip Report
    10 May 1957. 1

  13. Trip Report - Discussions on RS-11 and AS-3 Equipment
    10 May 1957. 1

  14. Trip Report - RD-122 - AS-3
    24 June 1957. 1

  15. Trip Report - RD-122 - AS-3
    18 December 1958. 1

  16. Trip Report - AS-3
    17 April 1959. 1

  17. AS-3 Agent Communication System (Project 2108)
    13 December 1956. 1

  18. Semi-Automatic Agent Communications Set, AS-3 (Project 2108)
    30 July 1957. 1

  19. TP-3 Motors
    19 November 1957. 1

  20. Preliminary Evaluation of TP-3, Hellschreiber Transistorized Printer
    19 December 1957. 1

  21. Trip Report - AS-3 Tests (hints to Hellschreiber usage)
    23 April 1959. 1

  22. Development of a Minature DC Motor for the TP-3 printer
    30 December 1959. 1

  23. Technical Notes on AT-3 Transmitter
    26 August 1960. 1

  24. Army Evaluation of AS-3 Equipment
    5 March 1962. 1

  25. Defects in AS-3 Prototype - Attachment 'A'
    Date unknown.

  26. Suggested AS-3 Accessories
    8 May 1959. 1

  27. Conference Report, Radio Station AS-3
    19 July 1957. 1

  28. Conference Report, Radio Station AS-3
    27 May 1957. 1

  29. Conference Report, AS-3
    31 October 1958. 1
  1. Sanitized copy approved for release by CIA on 14 February 2013 — 2 April 2013.

  1. Preliminary Instruction Manual for Radio Set AS-3
    CIA, 11 February 1959. 1

  2. RR/E-11 Receiver, Description
    Date unknown. 1

  3. AP-3A Power Supply Instruction Manual
    Date unknown. 1  Older version
  1. Pete McCollum, The AS-3 HF Radio Set
    Retrieved June 2020.

  2. Louis Meulstee, RR/E-11
    Wireless for the Warrior - Volume 4 Supplement, Chapter 142.
    October 2017. Retrieved June 2020.

  3. Louis Meulstee, AT-3
    Wireless for the Warrior - Volume 4 Supplement, Chapter 143.
    October 2017. Retrieved June 2020.

  4. H. Keith Melton, CIA Special Weapons & Equipment: Spy Devices of the Cold War
    New York, 1993. ISBN 0-8069-8732-4. Page 19.

  5. CIA, Request for Bids, AS-3
    30 April 1956. 1
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Crypto Museum. Created: Monday 29 June 2020. Last changed: Thursday, 20 April 2023 - 13:53 CET.
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