[Mondial]

Will, have you tried increasing the value of the .0007 uF cathode bypass cap of the 36? It seems later production increased the value to .0014 uF.

How short can you make the gimmick wire before the osc quits? If you make it really short, does it make a difference if you bring it near the other coil terminals?

There is an advantage to using harmonics when checking low freqs with your digital receiver. The receiver has a fixed bandwidth and resolution regardless of RX freq so you want to measure at the highest freq possible to minimize percentage error.

Say you can measure the RX freq to an accuracy of 5 kHz. If you can receive the third harmonic at 780 kHz to an accuracy of 5 kHz, then your accuracy of measurement of the fundamental increases to 1.66 kHz at 260 KHz, which is much better than if you measured it directly. If you used the fifth harmonic at 1300 kHz then the possible measurement error drops to only 1 kHz.