(c) 2000,2022 Peter McCollum

Early Military Equipment

Described in this section is "clandestine" equipment that was developed primarily by and for the U.S. military before 1945. Some of this equipment was used by the OSS at various times, but the primary user was probably Military Intelligence (or paratroops in the case of the PPN-2 Beacon).


The PRC-1 "Suitcase Radio"


PRC-1/RT-30 Radio Specifications



32 lbs


18" X 13.25" X 17.25"

Tube complement

Xmtr: 807, 6V6.

Rcvr: 6SG7, 6SA7, 6SK7, 6SL7, 6J5.

P.S.: 5R4.

 Input power

115, 150, 200, 220, or 250 VAC, 50/60 Cy.

Frequency Bands

2-5 MC, 5-12 MC

Power Output

 30 watts


J-37 key, hi-Z phones output (can be reconfigured for lo-Z ?). Xmtr xtal control only; rcvr tunes AM or CW.


A PRC-1 radio set. Image courtesy of Chuck Brydges, W4WXZ. Now in the collection of Richard Dillman, W6AWO.


The PRC-5 "Suitcase Radio"


PRC-5 Radio Specifications



 25 lbs


 11" X 10" X 4"

Tube complement


 Input power

 110/220 VAC, 50/60 Cy

Frequency Bands

4-16 MC in 4 bands

Power Output

 10-16 watts


A PRC-5 radio set, with a manual dated 21 June 1944. Image courtesy of Michael Crestohl W1RC.

Schematic diagram of PRC-5


This is an AR-11 transceiver, made by ARF Products. Note the strong similarity with the PRC-5 - it is clear that they made the PRC-5 as well. ARF was in River Forest, Illinois beginning in 1942. Image courtesy of George Briggs.


SCR-504 Radio Direction Finding Receiver

The SCR-504 was used for counterintelligence purposes, to aid in locating an enemy transmitter. It was mounted in a suitcase so that it could be fairly discretely carried on the street. Because of the internal loop antenna, rotating the set would change the signal strength, thus giving the operator an indication of the direction of the signal.

An SCR-504 RDF receiver. Note the loop antenna, and the eight tubes along the bottom. Image courtesy of the late Bill Howard.


Top view of the SCR-504, showing the whip antenna protruding through the case, and the operator's controls under the handle, allowing basic functions to be adjusted without opening the case. Image courtesy of the late Bill Howard.