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. A number of units were manufactured by the Farnsworth Television and Radio Corporation of Fort Wayne, Indiana.[1]
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The BC-342 was AC powered, allowing operation in fixed and mobile operation. It had a 470 kHz IF, crystal filter and used 10 vacuum tubes of the following types: two 6K7s as RF amplifiers, a 6L7 mixer, a 6C5 local oscillator, two 6K7s as IF amplifiers, a 6C5 CW oscillator (BFO), a 6R7 detector/1st AF, a 6F6 audio output, and a 5W4 rectifier. The first audio stage contained the detector as well, integrated into one circuit.[2]
In addition to the AC power supply, the BC-342 was wired for 12 volts for its tube filaments. The 9 tubes were wired so that three pairs of 6 volt tubes were wired in series. The audio output tube was a 6F6 in series with a pair of tubes, a 6C5 and a 6R7, along with a balancing resistor. The 12 volt DC versions of BC-312 used similar connections. Models of the BC-312 designed for 24 volts DC used sets of four 6 volt tubes each in the series filament strings, with an 12A6 audio output tube in series with a resistor. All BC-312 used a dynamotor to supply B+ from the DC source.[1]
The BC-342 was similar to a number of radio receivers used in military vehicles and aircraft during World War II such as the BC-348. There was a general requirement for ruggedness and stability, so a heavy, screened chassis and case was employed to minimize drift and oscillator instability due to temperature changes and vibration.[3][4][5]