It is a simple circuit, whose development can be monitored with the 100 MHz equipment of my shack/lab (oscilloscope, frequency counter). So I dediced to give it a try.
After I built the oscillator, buffer and diode-ring mixer I checked waveforms on two "test points" as identified on this modified schematic diagram:
On TP1 the waveform is almost a sinewave. The small knee close to the top occurs both with a ceramic resonator and a quartz. It also gets worse when the resonator is pulled upwards: what is causing it? How to fix it?
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| Probe was 10x, so 2V/div, AC coupling |
Then I measured voltage on TP2, with diode ring mixer installed but without the output transformer; the effect of diodes is evident:
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| Probe was 10x, so 2V/div, AC coupling |
And finally a glimpse at my ugly Manhattan style (probe on TP1):
