The previous interesting cheat got me intrigued. Could I improve CW and SSB reception with a simple change? As simple as adding a capacitor in the right place?
I was setting up for aligning the IF and front end stages, but I got sidetracked by this idea.
I thought the best place to insert the BFO signal would be the screen grid of the last IF stage. The best way to get it would be from the anode of the BFO triode. The largest capacitor I had that could take the voltage with good margin was 10 nF. The change was barely noticeable and hard to evaluate as the BFO frequency also changed. I decided to connect 8 of them in parallel.
Even that did not make a convincing improvement. It is possible that a much bigger capacitor is needed. Or a different way of connecting it. Or perhaps remove the 5 nF capacitor from anode to earth as that one swallows much of the signal.
While investigating where to connect the capacitor I found an incomplete soldering joint.
For the picture I lifted one leg of the resistor away to show that it was not properly soldered.
I don’t know how long it has been like that. Perhaps since it was built. Tension kept it pressed against the right tube socket leg. Therefore functionality was not affected. I choose to solder it in place.
So that is part of what has kept me busy instead of aligning the receiver. Which I should get around to do.