The SCR-399; “Mobile communication unit” was developed for long-distance communication during the second world war. The US Army was looking for improvements in the transmission range, flexibility and durability compared to the then used SCR-197 and SCR-597 transmitters. In 1942 the Hallicrafters HT-4 was selected as the transmitter for the SCR-299, 399 and 499 and received the military identification number BC-610. Until this selection, the Hallicrafters HT-4 was a respected transmitter that was originally built for use by radio amateurs.
The first radio station of this series was used on 8 November 1942 during operation TORCH where a company of the 829th Signal Service Battalion built up a first communication network that could send messages from the landing beaches to the bases in Gibraltar. Despite the problems with unloading the radio stations from the landing ships, the radio stations from this series had been employed until the installation of the “Permanent Army Command and Administrative Network Stations.” General Dwight Eisenhower complemented the work of the SCR-299, 399 and 499 radio stations during the successful reorganization of the US Army and the last victory over the Germans in Kasserine pass in Tunisia. The broadcasting range of the radio stations exceeded all expectations. There are connections made over distances of 3700 km. The SCR-299, 399 and 499 radio stations provided a reliable radio connection with England during the “North African Campain” and during D-day in Normandie where the radio stations were also used by the English Airborn divisions. Also during the invasion in Sicily and Italy almost all communication was via these radio stations. War correspondents made frequent use of these radio stations which were offered to them by the second and third army “Group Communication Teams.” It has been a time that these radio stations were their only link with England for passing on the news.
This radio station existed in three variants; the SCR-299, built into a Dodge panelvan K-51; SCR-399, built into a shelter / container on the back of the GMC truck and the SCR-499, the set can be used separate and installed in buildings.
The radio station is designed for long-distance communication between 1 and 18 MHz. and could, as said before, bridge distances up to approximately 3700 km. Broadly speaking, the radio station consisted of the following components;
- BC-610; transmitter with a capacity of 350 watts
- BC-312; receiver operating on 12 volts
- BC-342; receiver operating on 115 volts
- BC-614; “Speech amplifier” the pre-amp
- BC-939; Antenna tuner
The BC-610 is a Hallicrafters HT-4 transmitter which was originally built as a transmitter for radio amateurs in America. The station has been adapted for use by the US Army. This tube transmitter was built so solidly that it functioned in almost all circumstances. About 25,000 of these transmitters have been produced for the US Army.
BC-312 and BC-342
These receivers were only different in the power supply. one works at 12 volts and the other at 115 volts. These receivers were used extensively in various radio sets during and after the Second World War. The receiver could receive from 1.5 to 18 MHz.
The Speech amplifier is the pre-amp of this radio set which converted the three input signals into a signal that the transmitter can handle. One could use this radio station for transmitting morse local, remote morse via a field telephone line, local telephony and remote telephony via a field telephone connection. All these options were combined with the Speech amplifier.
The antenna tuner is actually part of the transmitter, this is always shown together and as far as I know not used in other sets except the successor of this set which was used by the Dutch army until the 1980s.
This radio station also includes various accessories packed in three boxes and two reels with telephone cable. There is a chest for the transmitter; the Chest CH-88-A; which is filled with tuning units and coils with which the transmitter could reach its frequencies. There was also a large chest; the Chest CH-119-A; containing various tools and rolls with cable. The third box is also the bank and was filled with mainly spare parts and the antennas.
The radio station also comes with a 3.5 KW PE-95 unit.