Post WWII US Army Radios & Radio Teletype Shelters


26 on Old Truck

The AN/GRC-26 Series

The first high power mobile radio systems were the SCR-299, and later the SCR-399, during WWII.  It was from these that the first AN/GRC-26 evolved in approximately 1950.  The early sets were installed in GMC CCKW 2-1/2 ton trucks and eventually were mounted in many different 2-1/2 ton series of trucks.  My unit had the 26A version mounted in M-211 and M-135 GMC trucks in 1969.  We will list the components found in each version, in the sections below.

From The Manual

The 26 series consists of a transportable assembly of equipment providing facilities for transmission and reception of radio teletype signals on an frequency shift basis over a frequency range of 2 to 18 Mhz. Maximum power output is approximately 400 watts.  Facilities are provided for operation of full duplex, half duplex or one way reversible circuits. CW and AM may be used alone or simultaneously with teletype operation. Shelter S-55/GRC, containing all the communication equipment is normally transported by a 2-1/2 ton cargo truck.  Power unit PE-95(*), installed in a 1 ton trailer, is towed by the cargo truck.  The complete radio set may also be transported in a C-82 aircraft.

CW and voice can be used in motion or at a halt. For teletype communication it is recommended that the vehicle be brought to a halt.

For mobile, one way reversible operation, three whip antennas are used; two for receiving and one for transmitting.  Mobil at halt operation normally utilizes whip antennas.  If time permits, however, a doublet transmitting antenna should be erected to improve transmitted signal strength.  For semi-fixed installations, doublet antennas are used for both transmitting and receiving with two receiving antennas for dual space diversity reception.

The internal equipment consists of Joint Army/Navy receivers, transmitter, teletype equipment and radio teletype components.  These have been modified for this application.  Components of the radio teletype equipment are in special, compact, shock mounted cabinets to allow them to be located in a limited amount of space.  All operating components are located on tables and shelves in the shelter.

The "Plain" Model

The "A" Model

The "B" Model

The "C" Model

The "D" Model