[MRCA] looking for BC-223 oerators

[W7QHO at aol.com]

Meir,

Got a BC-223A up and running for Ft. MacArthur a couple of years ago.

First off, the "interrupter" is a buzzer that generates the MCW tone.

Odd design choices in this rig with 20W WW resistors used in several circuits 
where a 1 watt rating would have been conservative.  Found several of these 
open on initial checkout as well, and blew an oil filled cap soon after initial 
power up.     

On phone, the rig initially modulated 100% neg, but only 40% in the upward 
direction.   Problem turned out to be incorrect biasing of the 46 speech amp 
tube.   The bias is derived from a fixed resistor string in the PA grid circuit 
which I replaced with an equivalent potentiometer.   Was then able to adjust 
the bias to get symmetrical modulation.   Significant FM component at first but 
the set responded well to the neutralization trick the same as the BCC-375. 
Audio sounds very good.

Get 18 watts of carrier out using a 500 volt HB supply, phone and CW.   
Significantly less power out on crystal control, BTW, and xtal currents very high.

Fun   little rig.   Good luck.

Dennis D. W7QHO
Glendale, CA



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