SCR-197
Encyclopedia
The SCR-197 was a ground mobile high frequency
radio
station used by the United States military prior to and during World War II
, notably during the Battle of Wake Island
in 1941.
power output of 400 watt
s. Radio receivers consisted of three BC-342
and one Hallicrafters
S-20R "Sky Champion". Also provisioned was a BC-119 control box. The complete set was housed in a K-18 truck and K-19 trailer combination. A 45 foot vertical antenna
was used for sending and a 15 foot whip used for receiving. Power could be optionally supplied by power mains or portable generator units: one PTO
driven GN-42-A generator for the transmitter and two small PE-75 skid mount
ed units for the receivers. The SCR-197 set was later replaced by the SCR-299
.
High frequency
High frequency radio frequencies are between 3 and 30 MHz. Also known as the decameter band or decameter wave as the wavelengths range from one to ten decameters . Frequencies immediately below HF are denoted Medium-frequency , and the next higher frequencies are known as Very high frequency...
radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
station used by the United States military prior to and during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, notably during the Battle of Wake Island
Battle of Wake Island
The Battle of Wake Island began simultaneously with the Attack on Pearl Harbor and ended on 23 December 1941, with the surrender of the American forces to the Empire of Japan...
in 1941.
Specifications
The SCR-197 mobile station consisted of the BC-325 radio transmitter with a frequency coverage of 1.5 to 18 Mhz and an RFRadio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
power output of 400 watt
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...
s. Radio receivers consisted of three BC-342
BC-342
The BC-342 was a World War II U.S. Army Signal Corps radio receiver with high frequency band coverage. It was a 115 Volt AC version of the BC-312 receiver, used primarily as part of field installations...
and one Hallicrafters
Hallicrafters
The Hallicrafters Company manufactured, marketed, and sold radio equipment beginning in 1932. The company was based in Chicago, Illinois, USA.-History:William J. Halligan founded his own radio manufacturing company in Chicago in late 1932...
S-20R "Sky Champion". Also provisioned was a BC-119 control box. The complete set was housed in a K-18 truck and K-19 trailer combination. A 45 foot vertical antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
was used for sending and a 15 foot whip used for receiving. Power could be optionally supplied by power mains or portable generator units: one PTO
Power take-off
A power take-off or power takeoff is a splined driveshaft, usually on a tractor or truck, that can be used to provide power to an attachment or separate machine. It is designed to be easily connected and disconnected...
driven GN-42-A generator for the transmitter and two small PE-75 skid mount
Skid mount
A Skid mount is a popular method of distributing and storing machinery for the military and industry, simply put, the machinery at point of manufacture is permanently mounted in a frame or onto rails or a metal Pallet...
ed units for the receivers. The SCR-197 set was later replaced by the SCR-299
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...
.
See also
- List of U.S. military vehicles by supply catalog designation
- List of U.S. Signal Corps Vehicles
- Signal Corps RadioSignal Corps RadioSignal Corps Radios were U.S. Army military communications components that comprised "sets". Under the Army Nomenclature System, SCR initially designated "Set, Complete Radio," and later "Signal Corps Radio," though interpretations have varied over time....
General references
- TM 11-227 Radio Communications Equipment 1944
- TM 11-487 Electrical Communication Systems Equipment 1944
- TM 9-2800 Military vehicles 1943
- TM 11-241
- TM 11-805
- TM 11-900
- SNL G517 K-19 trailer
- TM 10-1702 GMC, 1-ton, 4 × 2 (LC), COE, K-18, Model No. CF-351
- SNL G620 K-18 truck
External links
- http://books.google.com/books?id=YtcDAAAAMBAJ&pg=PA68&lpg=PA66&dq=signal+corps+radio+tractor&lr=&as_brr=1&output=html good shot of trailer interior
- http://images.google.com/hosted/life/l?q=gasoline++source:life&imgurl=f32c60f70c44515c
- 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
- http://www.oldradios.co.nz/gallery/anchors/HALLICRAFTERS%20S20R.html s-20r receiver
- http://books.google.com/books?id=_WsG39lnR9cC&pg=PA153&dq=k-19+trailer&ei=5N10SfC6KI3CNoj07I4E on wake island
- http://www.mapleleafup.org/forums/showthread.php?t=12699 survivor found
- http://www.youtube.com/watch?v=gloax6OFV4w&feature=related sky champion