Having had success with GPS-
See the schematic of my original LO modification here.
Now look at the diagram on the right. Ignoring the MMIC, the revised varactor tuning is essentially the same as before, however as in OZ5N’s circuit, the varactor tuning is connected directly to the crystal via a 22pF capacitor and the 47pF capacitor has been changed to 22pF.
I call that a success! What is more, my 67ele QLY appears to be working … with the
usual weak signal from GB3CSB on 3400.985MHz coming in with the occasional 100Hz