On Sun, 11 Jun 2006 10:47:31 GMT, W3JDR wrote:

John,

Most overtone crystals are designed for operation on their series resonance.
There is also a parallel resonance, usually a few khz higher than the series
resonance. The fact that your oscillator is putting out a signal a few khz
higher than the frequency marked on the crystal is a good indicator that you
might be operating the crystal in the parallel mode.

You shouldn't have to resort to any 'tricks' like operating it in its
fundamental mode & multiplying, or putting frequency 'pulling' components in
the circuit. It should come very close to the marked frequency if you use
the correct circuit.


Can you refer to a circuit that's similar to yours so we can look at it and
recommend what might be wrong?

Joe
W3JDR


"John Wilkinson" wrote in message
.. .
Hi,
I need a good second LO at 44.545MHz.
I have a few crystals that I bought, that are say they are 44.545MHz, but
are really 44.548MHz. I tried pulling the frquency somewhat, but to no
great avail.
I have read that overtone crystals are hard to pull.

Does anyone know where I can get good quality crystals at this frequency?

Or how I may combine some easily available crystal frequencies to get
either 44.545MHz or 45.455MHz?

Best regards,
John.

Hi,
Thanks,
The circuit I am using is a simple JFET J310 with a tuned drain circuit.
The XTAL is connected from the gate to the drain via a 10nF cap.

Another was a colpits oscillator, with a 2N3904 transistor. The XTAL was
used in palce of the usual L and C.


Regards,
John.