RCA BC-224-A - the First BC-348


Posted on Feb 6, 2014

The mid to late 1930s reflected a curious mixture of old and new thinking in aircraft radios, led by brilliant engineers in such companies as Aircraft Radio Corporation and RCA. The example below should endear itself to every radio amateur growing up in the 1940s or 1950s, because it was the first of the BC-348 series of aircraft receivers. A clos


RCA BC-224-A - the First BC-348
Click here to download the full size of the above Circuit.

e look at its front panel will reveal the same controls that are on all the later BC-224/348s, with the addition of a "heater" switch that provided power to the thermostatically regulated local ("heterodyne") oscillator compartment to provide stability at high altitudes, and some relocation from the more familiar positions of the others. (The BC-348-J, N, and Q also deleted the antenna alignment knob, of course. ) This innovative receiver has a circuit diagram that looks very similar to its later counterparts, as well. There was a curious inclusion of a short transmission line between the left and right side of the receiver along the bottom edge of the front panel, presumably to make antenna connections easier on some aircraft installations. A short wire from the "A" terminal on the left to an inexplicaby different shaped terminal 45 ° downward from it was required to connect the transmission line. The familiar PL-Q103 and PL-P103 eight pin Jones style power plugs were identical to the later models, and though the FT-154 shock mount did not have the same depth as the later FT-154-*, it appears identical to the casual glance. Installed in a typical setting, a BC-224-A (above) in NASM`s unrestored O-47A observation aircraft shows its age, but also the ambience of an operational aircraft communications receiver. The tuning knob has suffered from deterioration of its paint in the storage environment for so many years, but also...




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Subwoofer Equaliser
    Speech Recorder (ISD2560)
    Disco light effect with PIC16F84A
    Digital Stopwatch 0-60sec
    Solid-State Windshield-Wiper Delay
    33v and 5v dual tracking regulator using lt3692 dc converter
    10 band equalizer
    project armageddon processor
    s1d13700 arduino documentation
    Bidirectional motor control using L293 driver
    Polarity Reverser
    Basic Connection circuit diagram INA326 327 signals and power
    Single-ended Class A amplifier circuit diagram of 6N1 + 6P3P



    Top