Hello Tom and Steve,
Some years ago I built a 3.5MHz QRP TX using a 3.58MHz ceramic resonator.
After some experimenting with the caps (to compensate the temperature drift
of the ceramic resonator and the FET) I obtained a drift of less than
10Hz/hour. Divided down to 136kHz this would be a drift of 0.4Hz/hour, good
enough for QRSS at 3 or 10 sec/dot but maybe a bit on the edge for the TA
stuff at 1 min/dot or slower.
The frequency range was 75kHz at 3.5MHz, so that would be about 2.8kHz at
136kHz.
73, Rik ON7YD
At 09:10 14/08/2002 +0100, you wrote:
Steve
Buy one of the ceramic (as opposed to quartz) resonators in the 2.5 MHz
region and use in a VXO circuit. About 100pF variable gives me band
coverage. Divide by 18 for 136 output, any drift is also divided by 18.
It's nice and stable for normal CW operation but I have never actually
measured its stablilty so have no idea if good enough for QRSS.
73, Tom G3OLB
In message <000a01c242fb$2b68ace0$7211f4cc@jsm>, Steve McDonald
<[email protected]> writes
>Perhaps someone who has already 'been there' can offer their advice.
>I would like to start building the exciter stages for what will be my
136KHz tx
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