Hi
The original question related to crystals that ran down into the 10’s of KHz
range. For those, a
high resistance is not unreasonable at all. For more “normal” AT cut
resonators in “big" packages
it is not unreasonable to expect the resistance on the fundamental to be
approximately the same
as the frequency in MHz. As the overtone goes up, it is not unusual for the
resistance to go up
as the overtone number. There are an almost infinite number of qualifiers on
all of that.
The range of crystal resistance between things like 3 MHz AT’s and 32 KHz
watch crystals is one
of the things that makes building an one size fits all oscillator difficult.
Bob
===============================
Folks,
There was a discussion about measuring 32 kHz crystals in the VNWA Yahoo
group recently, and Tom posted a note describing how to do it and get
sensible results:
https://groups.yahoo.com/neo/groups/VNWA/files/A1%20DG8SAQ/
https://groups.yahoo.com/neo/groups/VNWA/files/A1%20DG8SAQ/Measuring_32kHz_crystal.pdf
It struck me that a noise generator and the spectrum display for the Airspy
might be another low-cost way at least for HF crystals:
http://www.rtl-sdr.com/spectrum-spy-new-spectrum-analyzer-software-for-the-airspy/
http://www.rtl-sdr.com/using-the-airspy-as-a-low-cost-spectrum-analyzer-with-spectrum-spy/
73,
David GM8ARV
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv
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