[Elecraft] Crystal Tester Trouble!

[Don Wilhelm]

Steve,

If you have a large value trimpot at the output, that could cause 
problems.  Try a pot in the range of 500 to 1k.  You may have to change 
the values of the two capacitors in the base/emitter part of the circuit 
for use at a lower frequencies.  The capacitors control the feedback, so 
some experimenting may be in order - either too much feedback or too 
little can cause a failure to oscillate.

Remember that oscillator is intended to develop a huge output that is 
handy for troubleshooting - the output is easily measured with an RF 
Probe and DMM.  If you want a low level oscillator better suited for 
alignment purposes, I would suggest that you use a circuit similar to 
that used in the Elecraft XG1 or XG2 - download the manuals and take a look.

73,
Don W3FPR

Elecraft Reflector wrote:
> Hello Group!
>
> I have built two crystal testers from the circuit shown on page 5, Appendix E of the K1 construction manual. The components used were exact values. The circuit works fine with crystals from 10MHz and upwards but good 80m crystals will not fire up the oscillator. I have tried a fair few good 80m QRP crystals (standard package) but no joy. Has anyone had the same problem? Any ideas how to solve it please?
>
>