Why do you think a 30 MHz xtal is third overtone? Not impossible but unusual.
No such thing as oscillating at 2nd overtone.
Even as a multiplier the collector load should be tuned, which it isn't.
Keith
Maybe it's a matter of layout and connected load. Because the cicrcuit isn't a stable overtone oscillator, many parameters can play a role.but i would like to figure out why the original circuit works while mine do not .
Maybe it's a matter of layout and connected load. Because the cicrcuit isn't a stable overtone oscillator, many parameters can play a role.
It's a very simple class C output stage. A sufficient drive level is required to get any output, of course.There is an inductor shorting out the 2N2369A base-emitter, for example.
Do you know for sure, if the original product uses an overtone crystal?
If you check the 2000 c-mag catalog for the HC49/4H size, you'll notice, that 25 -40 MHz is offered both as fundamental and 3rd overtone type, but the ppm numbers are better for overtone. It's basically the same with present IQD products. So it's understandable, why a radio devive may use an overtone crystal, while processor crystals are mostly of the fundamental type. The fundamental frequency range has been apparently extended for recent SMD devices.I am not sure it is an overtone crystal....As they do AT fundamental cut up to 40MHz it would be strange to go for a 3rd harmonic at 30MHz.
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