U.S. Clandestine Radio Equipment


Written/compiled by Peter McCollum

This site was (I believe) the first important online documentation of CIA communications equipment.


I can be reached at:

Saipan 1959 (at) gmail (dot) com [remove spaces, substitute '@' and '.' where needed]

(c) 1998, 2024 Peter McCollum


  Although this site was graciously hosted for a good many years by Don Reaves W5OR,
it is now hosted by Richard Brisson at www.spyradios.com


Some recommended sites for more information:

The CIA’s “Electronic Reading Room” site at https://www.cia.gov/library/readingroom/ .

Louis Meulstee’s site, especially the “Volume 4 update” pages: http://www.wftw.nl/b-one-default.html .

Crypto Museum: http://www.cryptomuseum.com/index.htm .


A great book is available! It is Volume 4 of the "Wireless for the Warrior" series by Louis Meulstee and Rudolf Staritz, and it is an encyclopedia of clandestine radios from all over the world. Over 230 sets are covered, with 850 pictures - 692 pages in all. I contributed much of the info for the U.S. sets.

NOTE: I do NOT have a financial interest in sales of the book, although I certainly feel it is a great reference, and by far the biggest/best book ever published on this topic. Contact Louis for availability, via his site at http://wftw.nl/ . Also note that Louis has been posting a huge number of Supplement chapters for free download – over 300 so far: http://www.wftw.nl/supplement.html .


Introduction (this page)

World War II: OSS and Military Equipment

The SSTR-1 Strategic Services Transmitter-Receiver

The "Joan-Eleanor" System

Other OSS Equipment

Early Military Equipment

CIA Equipment

The RT-1-B and URT-11 Transmitters

Radio Station RS-1

RT-3 Variants

The RT-4 Transmitter

The RS-6 HF Transceiver

The RS-511 Attache Case Radio

The CK-8 Coder/Keyer (military GRA-71), and other coder/keyers

The RS-13 HF Radio Set

The AS-3 HF Radio Set

The RS-48 HF Radio Set

The RS-49 HF Radio Set

Surveillance and Bugging Devices

TAR-224 Transceiver

Other CIA Sets

Observed Nomenclature

Beacon Transmitters

RDR Corp., N.Y.C.

Military-oriented equipment

The GRC-109 Transceiver

The Delco 5300 Series HF Transceiver 

Modular Radio Station (military PRC-52)

The "Village Radios"

Other Information

Observed Serial Numbers

Mystery Radios

Selected Foreign Sets

Encryption via a One-Time Pad

Training, Tradecraft and Technology

Signals Intelligence

Miscellaneous Non-radio Items

References/Bibliography, Miscellaneous, and Notes


This document is dedicated to the men and women who served our country as the designers and users of clandestine communications equipment.


Since before the time of Sun Tzu, communications have played an important role in the collection of intelligence. With the advent of effective portable radio technology in the 1930's, it became feasible for an operative to send and receive information quickly and independently from within enemy territory.

The purpose of this research paper is to document facts, observations, anecdotes, and stories about clandestine radio equipment as used by the United States. The specific equipment presented here was chosen either because it had a major role in clandestine work, or because sufficient information was available to the author. Pictures and brief descriptions of additional equipment can be found in books by H. Keith Melton (see the Bibliography); and also at various sites on the World Wide Web.

Wherever possible, this document goes into technical detail on the equipment, and some conclusions are drawn regarding the intended purpose for certain features. Some comments are made of a practical nature, for those people that own one of these sets and would like to restore it or use it for Amateur Radio communications.

Is it real "Spy Equipment"?

While researching the equipment described on these pages, sometimes it is not entirely clear if an item is really qualified to be called "spy equipment". I believe that there are many possible criteria for labeling an item as being "OSS" or "CIA". This becomes important to someone who is considering buying or selling such an item. Following are some ideas of possible criteria that could be used to decide the legitimacy of an item. I will use some CIA items to illustrate these examples:

1.  The item was designed (in whole or in part) by CIA personnel. Example: The RS-1 set.

2.  The item was designed by a contractor, but to CIA specifications. Possible examples include many of the Cold War sets, such as the SRR-4.

3.  The item was a commercial item, but was bought under a specific CIA contract. Example: Certain Hammarlund SP-600 receivers.

4.  The item was actually constructed by CIA personnel. This criterion probably applies mostly to prototypes.

5.  The item has a CIA-specific designation, such as RS-x, RR-x or RT-x.

6.  The item was "standard issue" to a number of CIA employees. Example: The Minox model "B" camera.

7.  The item was adopted from a different intelligence organization, including foreign (such as SOE or MI-6), but widely used by CIA personnel.

8.  The item was adopted from the military, but widely used by CIA personnel. Example: The GN-58 hand-crank generator often used with the RS-1 set.

9.  The item was adopted by the military from an existing CIA item. Examples: The AN/GRC-109 and RS-6 sets.

10.The item was carried/used by a CIA employee.

11.The item was carried/used by a famous CIA employee.

12.The item is known to have been used in a specific spy operation.


Discussing some specific cases:

The early Minox cameras are often called "spy cameras". They were bought in large numbers by intelligence organizations all over the world, and used in many real spy operations. However, the exact same models and accessories were also bought by tourists traveling in Germany. Is any Minox a "spy camera"? Or only those that were owned by CIA personnel? Or only those that were purchased under a CIA contract? Or only those that were actually used for spying?

The AN/GRC-109 radio set is essentially identical to the CIA's RS-1 set. Only the markings are really different. Some GRC-109 sets were likely operated by CIA personnel in Vietnam. And, some RS-1 sets were used by Special Forces personnel, before the GRC-109 was available. Is either of these sets 'only' a CIA set or a Special Forces set?

The RS-6 set is a CIA design with a CIA designation, but the military procured the majority of the sets that were made, and they did not assign a military designation to it. Is the typical SAC-surplus RS-6 set a "spy radio"?

Perhaps the conclusion is that whenever possible the facts and origins of an item should be spelled out, and each collector or researcher should describe his/her criteria for labeling something as a "spy item". It is partly inaccurate to say that an RS-6 set is a "SAC survival radio", or that a Minox camera is a "spy camera".

In Remembrance of Veterans


Bud was a veteran of the Office of Communications, and was active in the retiree’s community. He told me many interesting stories, and gave commentary on a variety of CIA radio gear. Bud was a principle engineer on the RS-49 project. When I would ask him a question about radio equipment, he would query the “GrayBeards” (retired Commo veterans) to try and get me an answer if he didn’t know himself. For example, he identified the RT-4 transmitter after seeing a picture. Bud died in a car accident in 2012.

Walter “Wally” Szuminski

Mr. Szuminski was one of the 3 TSD men that were imprisoned in Cuba as described here:
https://www.cia.gov/library/readingroom/docs/DOC_0000624340.pdf . Their story is also in Keith Melton's "Spycraft" book. Mr. Szuminski helped me identify TSD-related items, such as the ST-2A transmitter.

An excerpt from his obituary:

Walter Edward Szuminski, age 86, died on 31 July 2016 in Winchester, VA. Walter graduated from the Boston Trade High School in 1947. He worked at a local radio station while serving in the Army Reserve. He joined the Central Intelligence Agency in 1950 and served in many countries over a 30-year period. He was awarded the Distinguished Intelligence Cross in April 1979 by Admiral Stansfield Turner, then Director of the CIA, for exceptional heroism. After his retirement in 1980 he continued to work as a contractor for the next 20 years.”

"Trapper" Drum

Following is an excerpt from the obituary of James H. "Trapper" Drum, who died December 15, 2002:

"During World War II he served with the 84th Infantry Division, 334th Battalion (the Railsplitters) as a company commander. After suffering severe wounds in Gilenkerchen, Germany, November 1944 he was retired from the Army. The Drums moved to Washington, DC in 1945 where he [eventually] joined the CIA. Under Allan Dulles he was asked to develop and direct a division he helped name, the Technical Services Staff which has evolved into the present day Office of Technical Service. "The Drum Award" was established in his name in 1995 to recognize extraordinary contributions to selected recipients in the Agency."

Bob Olsen

I learned in 2002 that Bob Olsen had died a couple of years previous. Mr. Olsen was the first CIA communicator that I had met back in about 1996, at a reunion of former Saipan residents. An interview with Mr. Olsen is found in the "Miscellaneous, Notes, and Bibliography" section.