United States Army Signal Corps

BC - 312 Radio Receiver; part of SCR - 499/A

Swiss Army Communication Sets
Foreign Military Communication Equipment
United States / U.S.A.
BC-324 / BC-312 / BC-348
Receiver Family
Equipment List
Swiss Army Manuals

überarbeitet am 23.11.2010

The receiver BC-312 has been built by several contractors in the U.S. for the US Signal Corps in World War II and has been used as receiver in several wireless stations.
The Swiss Army used this receiver in their Funkstation SE-402 / SM 46, an American SCR-499/A bought as war surplus.

Single conversion, I.F. 470 kHz

Analog dial


1,5 - 18 MHz



Antenna tuner, AGC/MGC

The receiver BC-312 comes in a rugged metal case with black wrinkle finish, it is 46 x 23 x 24 cm wide and has a weight of 22 kg.
The BC-312 is intended to be powered from a car battery from 12 - 14 V DC, the high tension is generated by a rotary converter, a so called "Dynamotor".
The BC-312 has been used with the shortwave station SCR-499/A which could be remote controlled. The signals have been received at the remote site with the BC-312 and the signal had to be fed to the transmitter via a field telephone line. At the transmitter site, there was another receiver very similar in construction to the BC-312, the mains operated BC-342.

In the middle of the front panel, You find the frequency dial, a rotating round dial behind a dial window, a mechanical shutter let's You read only from the dial of the active band. The bandswitch is located at the left below the frequency dial, the coarse tuning knob at the right. Slightly above the main tuning dial, You find the mechanically coupled fine tuning or "vernier" dial with a mechanical lock.
In the right lower corner of the front panel, You find the main connector for all signals coming from the SCR-499/A, the main switch combined with manual (M.V.C.) and automatic (A.V.C.) gain control and the send / receive operation switch.
The volume control, the BFO switch for the reception of CW and single sideband signals and the BFO beat note control are found in the right upper corner of the front panel; a dial illumination control at the right and an antenna tuner control at the left side of the dial window.
A coaxial and a random wire antenna connector are located in the left upper corner of the front panel and an earth terminal in the left lower corner.

To operate the receiver, connect the correct voltage, a suitable antenna and an earth connection to the respective wire terminals. Set the operation mode switch to receive and the power switch to A.V.C., You should hear the dynamotor working.
Use the band selector to switch to the 5000-8000 kHz band and the main tuning knob to locate the signal of radio "Deutsche Welle" from cologne near the 6,075 MHz marks, the vernier tuning is helpful, when You have identified the signal, to peak the signal. Use the volume control to adjust the volume, the C.W. OSC switch should be set to OFF, it should only be activated when You intend to listen to morse code transmissions in the ham bands.
All controls seem to be a bit scattered over the front panel, but the receiver has many features of a more modern all wave receiver - remember, it has been designed in 1936 when frontpanel control ergonomics has not yet been a subject of discussion.

The BC-312 is a rugged and uncomplicated receiver to work on, but sometimes You get problems with the mechanical dynamotor (works like a motor with a mechanically coupled alternator) and many sets have been modified to mains operation with a external mains power supply bypassing the dynamotor.

© Martin Bösch 23.11.2010