This page is a collection of articles about the venerable BC, LM and SCR series of heterodyne frequency meters.

Articles and information about one BC or LM unit probably apply to the other nomenclature as well.  If you have more information,
please send it to me at [email protected]

ARRL’s BC-221 VFO conversion article 1936 Technical Review of the LM series  
K4CHE – Using the BC-221 as a VFO (lots of information) Converting BC-221 to Solid State xx
K4CHE – Using the BC-221 as a CW Transceiver Converting BC-221 to FET, Solid State xx
LM-13 Maintenance Handbook (likely applies to other models also) AA8V’s RF Amplifier for BC-221 xx
Frequency Measurement with the BC-221  Simple Regulated Pwr Supply for BC-221/LM’s (see page 10) xx
BC-221 (and LM-series) Notes from unknown author  LM-8 Original Power Supply Schematic xx
Using the BC-221 as an Audio Oscillator (probably the LM’s also) LM-8 Power Supply – A few notes xx
“The Transistorized LM Freq Meter” xx xx

 

 

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