Re: Receive filter



Yes, I was right the first time -- the 747 is the weird old dual op amp, not the 7474.  However, the CWF-2 was a 3-position audio filter of 80-110-180 Hz bandwidths, and definitely MFJ.  Schematic here..  Certainly plenty of others out there, including the SOTAbeams variable and the Teensy 3.2 based DSP filter, Elecraft, 4-states, etc.

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