BC-191 and BC-375 Differences

On the surface, the two transmitters appear to be identical. They are 95% identical with the following differences noted.
  1. The BC-191 uses the BD-77M dyamotor with a 12 volt 52 ampere input, while the BC-375 uses the PE-73C dyamotor with a 26 volt 20 ampere input.

  2. The BC-191's tube filaments are all parallel fed from the 12 volt source through dropping resistors. The BC-375 tube filaments are arranged in three series strings (i.e. MOPA tubes, modulator tubes and speech amplifier/sidetone tube) that are parallel fed by a 26 volt source through dropping resistors.

  3. The BC-191 uses an antenna relay with a 12 volt coil, while the BC-375 uses an antenna relay with a 24 volt coil

  4. The BC-375 has an antenna terminal block on the upper right side with 5 connections (Antenna, Ground, Receiver, Load A, Load B). The BC-191 has its antenna block on the top right side with 6 connections. The extra connection is called CPSE and is connected to the RF ammeter and the variable capacitor  "O" (when the mode select switch "N" is in position #1).  These connections would go directly to ground on the BC-375E. On the BC-191, the CPSE post can be either connected to the ground post for some applications or the CPSE connection could be used in for static ground stations  (which used a 1/4 wave length wire antenna, this required a ground counterpoise, usually a 1/4 wave bit of wire laid under the antenna) .

  5. The BC-375 has three connectors on the left side (PL-61: low voltage & dynamotor control, PL-59: high voltage and PL-64: junction box). The BC-191 has an additional connector PL-74 used in some vehicular applications ( e.g. the M3A1 scout car which had a control box in the cable harness) .

    The SCR 193 was used in the following vehicles

    • 193A Light tank M2A3
    • 193B Scout car M3
    • 193C Combat car M1A1
    • 193D Scout car M3A1
    • 193E Dodge 1/2 ton command radio truck

  6. The BC-191 has a separate jack for the microphone and telegraph key, while the BC-375 uses a common jack for both.

           Special thanks to Mike, VK3CZ,  for providing the information in bullets 4) and 5)

For more BC-375 information, click on the following links.


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