[jrblasde]

The new components arrived this evening. I built a new prototype per my last description. I ordered a 3.3 μH coupled inductor and two individual 3.3 μH inductors. This time I went with axial leads; I found that they have much tighter tolerances.

I noticed that I get a better range of adjustment if I use an 82 pF fixed capacitor in parallel with a 20 pF trimmer. I still also find that the individual inductors perform best. However, my oscilloscope shows that I am obtaining a resonant frequency of 7.0 MHz. 

I decided to compare against a working IF can. I’ve been trying to create a replacement for the 1st IF can, but the 2nd IF can is original. I found that its resonant frequency was also close to 7.0 MHz. I am wondering if something about the way I have my test set up is introducing capacitance.

I’ve decided that the only way I will know if this is working is if I insert the device into the actual radio for a test under real conditions. Tomorrow I will attempt to solder it into the circuit.

One last note — it’s not seen in my photo, but I did use an experimental resistance on the primary side.

Joseph