The SCR-694 is a portable high frequency two way radio set that was used by the U.S. military during World War II. The SCR-694 provides transmission and reception of AM radiotelephony and MCW or CW radiotelegraphy within the frequency range of 3.800 to 6.500 MHz. The radio set consists of the BC-1306 receiver and transmitter along with ancillary equipment, not all of which was required in every signal mission.
The SCR-694 began to replace the SCR-284 from mid 1944, [1] with improved range and reduced weight (around half of its predecessor), though the latter continued to be used up until the end of the war. Designed to provide communication between moving or stationary vehicles or as a portable field radio set, the SCR-694 was originally intended for use by mountain troops and airborne forces but soon became the Army-wide standard at battalion level.
The SCR-694 saw use all over the army in many different theaters; notable instances include at regimental division headquarters during the Normandy invasion [2] and the Cabanatuan prison raid [3] as well as by scouts and reconnaissance units in the Pacific War. [4]
It was later replaced by the AN/GRC-9, which saw first documented use in the Korean war.
The Hallicrafters Company manufactured, marketed, and sold radio equipment, and to a lesser extent televisions and phonographs, beginning in 1932. The company was founded by William J. Halligan and based in Chicago, Illinois, United States.
A radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. Radio waves are electromagnetic waves with frequencies between about 30 Hz and 300 GHz. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating current, the antenna radiates radio waves. Transmitters are necessary parts of all systems that use radio: radio and television broadcasting, cell phones, wireless networks, radar, two way radios like walkie talkies, radio navigation systems like GPS, remote entry systems, among numerous other uses.
The arc converter, sometimes called the arc transmitter, or Poulsen arc after Danish engineer Valdemar Poulsen who invented it in 1903, was a variety of spark transmitter used in early wireless telegraphy. The arc converter used an electric arc to convert direct current electricity into radio frequency alternating current. It was used as a radio transmitter from 1903 until the 1920s when it was replaced by vacuum tube transmitters. One of the first transmitters that could generate continuous sinusoidal waves, it was one of the first technologies used to transmit sound by radio. It is on the list of IEEE Milestones as a historic achievement in electrical engineering.
The AN/ARC-5 Command Radio Set is a series of radio receivers, transmitters, and accessories carried aboard U.S. Navy aircraft during World War II and for some years afterward. It is described as "a complete multi-channel radio transmitting and receiving set providing communication and navigation facilities for aircraft. The LF-MF-HF components are designed to transmit and receive voice, tone-modulated, and continuous wave (cw) signals." Its flexible design provided AM radiotelephone voice communication and Modulated continuous wave (MCW) and Continuous wave (CW) Morse code modes, all of which are typical capabilities in other Navy aircraft communication sets of the period. It was an improvement of the Navy's ARA/ATA command set. Similar units designated SCR-274-N were used in U.S. Army aircraft. The Army set is based on the ARA/ATA, not the later AN/ARC-5. The ARA/ATA and SCR-274-N series are informally referred to as "ARC-5", despite small differences that render all three series incompatible. Like the AN/ARC-5, the ARA/ATA and SCR-274-N had AM voice communication and two-way MCW and CW Morse code capability.
The SCR-284 was a World War II era combination transmitter and receiver used in vehicles or fixed ground stations.
Radio-frequency (RF) engineering is a subset of electrical engineering involving the application of transmission line, waveguide, antenna, radar, and electromagnetic field principles to the design and application of devices that produce or use signals within the radio band, the frequency range of about 20 kHz up to 300 GHz.
The Wireless Set No. 19 was a Second World War mobile radio transceiver designed for use by armoured troops of the British Army. First introduced in 1940, the No. 19 began to replace the pre-war Wireless Set No. 11. Two modified versions were introduced, Mk. II in 1941 and Mk. III in 1942. An improved version from Canada was introduced in 1942 for use primarily with other forces. In British service, the No. 19 was replaced in the post-war era by the Larkspur radio system. Canadian-built No. 19s saw continued service for many years with a variety of users.
The SCR-536 was a hand-held radio transceiver used by the US Army Signal Corps in World War II. It is popularly referred to as a walkie talkie, although it was originally designated a "handie talkie".
The SCR-299 was a U.S. Signal Corps mobile military communications unit used during World War II.
Survival radios are carried by pilots and search and rescue teams to facilitate rescue in an emergency. They are generally designed to transmit on international distress frequencies. Maritime systems have been standardized under the Global Maritime Distress Safety System. Civil and military organisation's utilized different frequencies to communicate and no infringement on either sector would take place. For emergencies involving civilian aircraft, the radio frequency used is VHF 121.5 MHz and for military aircraft incidents, the frequency used is UHF 243 MHz.
The BC-610 was a radio transmitter based on the Hallicrafters HT-4 and was used by the U.S. Army Signal Corps during World War II.
The SCR-300, designated AN/VRC-3 under the Joint Electronics Type Designation System, was a portable radio transceiver used by US Signal Corps in World War II. This backpack-mounted unit was the first radio to be nicknamed a "walkie talkie".
The 807 is a beam tetrode vacuum tube, widely used in audio- and radio-frequency power amplifier applications.
The SCR-277 was a mobile, trailer mounted radio range set for radio guidance of aircraft. It was standardized by the U.S. Army in June 1941.
The BC-342 was a World War II U.S. Army Signal Corps high frequency radio receiver. It was used primarily as part of field installations such as the SCR-188A, but could be used with mobile sets such as the 2 1/2 ton mounted SCR-399. First designed at Fort Monmouth, New Jersey by the U.S. Army Signal Corps, it was built by various manufacturers including RCA. Many of the later units that are encountered today were manufactured by the Farnsworth Television and Radio Corporation of Fort Wayne, Indiana. Variants include the low frequency coverage BC-344 receiver, and the battery or dynamotor powered BC-312 receiver.
The AN/MRN-1 was an instrument approach localizer used by the Army Air Force during and after World War II. It was standardized on 3 July 1942. It replaced the SCR-241, and was a component of SCS-51.
The AN/MRN-3 was a marker beacon set used by the Army Air Force during and after World War II, it was standardized 23 October 1943, and replaced SCR-241.
The SCR-245 Radio was a mobile MF/HF Signal Corps Radio used by the U.S. Army before and during World War II, for short range ground communications, It was one of the first crystal controlled sets used by the Army.
The SCR-508 radio was a mobile Signal Corps Radio used by the U.S. Army during World War II, for short range ground communications. The SCR-508 series radio represented the Army's commitment to both FM and crystal tuning, and was used extensively by armor and mechanized units. The turret bustle of late series light and medium tanks was designed around this radio.
During World War II, the German Army relied on a diverse array of communications to maintain contact with its mobile forces and in particular with its armoured forces. Most of this equipment received the generic prefix FuG for Funkgerät, meaning "radio device". Occasionally the shorted Fu designation were used and there were exceptions to both these systems. Number ranges were not unique across the services so sometimes different equipment used by different services had the same FuG prefix. This article is a list and a description of the radio equipment.
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