CQM5660 IF-output.

If You want to connect an external IF-module to a CQM5660, it can be done very easily :

Solder one end of a small capacitor to resistor R406. (drain of the 1. mixer Q 402).
Connect coax cable centerconductor to other end of capacitor.
Connect coax cable screen to measuring point groundpin.
Connect the cable to the external IF-module.

IF-output

IF-output

I converted a CQM5662 to 1297.500 MHz FM, click here for more,
and connected the IF-output to antenna-connector on my IC735, and is able to listen from 1296.000 to 1297.500 MHz (at least), tuning the IC735 from 19.900 to 21.400 MHz.

In my CQM5662 second oscillator-Xtal is 21.855 MHz, but other CQM5662 use 20.955 MHz.
A "birdie" will be heard at the second oscillator frequency.

A buffer amplifier will improve the modification, minimizing the Xtal-filter mismatch.
CQM5662 can be used to monitor the original FM-frequency, simultaneously used as down-converter for SSB/CW.

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