SCR-299

The SCR-299 was a U.S. Signal Corps mobile military communications unit used during World War II.

History

The SCR-299 replaced SCR-197 and SCR-597, and was an effort to give a long-range communication advantage to the U.S. Army and its allies. To meet these demands, a high-powered radio transmitter was required — capable of infallible voice communications over 100 miles; self-powered; sturdy enough to work in all conditions, flexible enough to cover a wide range of frequencies; and able to operate in motion or at fixed locations.

Production began in early spring 1942. Out of the various sets sent from U.S. vendors, and after considerable experimentation, Hallicrafters Standard HT-4 transmitter was chosen as the desired radio's basis. The HT-4 transmitter's new version became known as the BC-610 transmitter. The receivers finally supplied were the BC-312 and BC-342, plus the BC-614 (speech amplifier), BC-729 (tuning unit) and BC-211 (frequency meter), along with the PE-95 (power unit). All these became part of the truck-and- trailer unit called the SCR-299 — later better known as the "mobile communications unit."

Though the original Signal Corps requirements were for communication points up to 100 miles, under favorable conditions these transmitters made and maintained contact over 2,300 miles of land and sea. [http://www.gordon.army.mil/ocos/ac/WWII/SCR299.asp The SCR299, Army Communicator United States Army Signal Center, Fort Gordon, GA]

SCR-299 was eventually replaced by version SCR-399 housed in the standard shelter HO-17 and mountable in any 2 1/2-ton truck. An air transportable version, SCR-499, became standard for the USAAF. [http://www.gordon.army.mil/ocos/Museum/AMC/radio2.asp Fort Gordon Museum, Transportable Sets]

pecifications

The SCR-299 was a complete mobile HF station on frequencies from 2-8 Mhz (and 1-18 Mhz using conversion kits) with transmitter output of 350 watts. The entire unit came in a K-51 truck except Power Unit PE-95 which was in a K-52 trailer. Power could either be supplied by the Power Unit and a 12 volt storage battery, or 115 volt 60 cycle AC commercial power and two spare 6 volt storage batteries. The power requirement was 2000 watts, plus 1500 watts for heater and lights.

The system could be remotely controlled up to a distance of one mile using two EE-8 field telephones and W-110-B Wire kit. Remote equipment was provided for remotely keying or voice modulating the transmitter, remotely listening to the receiver, and for communicating with the operator of the station.

Frequency Conversion Kit MC-503 gave coverage down to 1 Mhz. Frequency Conversion Kit MC-516 gave coverage to 12 Mhz and Frequency Conversion Kit MC-517 gave coverage to 18 Mhz. The receiver used a 9 foot whip antenna and the transmitter used a 15 foot whip antenna while moving. Alternately, it could use a 21 ft. whip antenna while stationary or a 45 ft. auxiliary wire antenna for 2.0 to 4.5 MHz coverage. [http://www.gordon.army.mil/OCOS/Museum/ScrComponents/scrPart2.asp Directory Of Components, The SCR299, Army Communicator United States Army Signal Center, Fort Gordon, GA]

Notes

ee also

*ARC-5
*BC-348
*BC-654
*Collins Radio
*R-390A
*Wireless Set No. 19
*List of U.S. Signal Corps Vehicles
*Signal Corps Radio

External links

* http://www.eht.com/oldradio/arrl/2004-04/April-2004.htm Hallicrafters HT-4, to War and home again
* http://www.gordon.army.mil/ocos/ac/WWII/SCR299.asp The SCR299, Army Communicator United States Army Signal Center, Fort Gordon, GA
* http://www.gordon.army.mil/ocos/museum/equipment.asp scr and bc list