I had a Morion MV89A that would stop oscillating when Vtune was more
than +600 mV.
So I cut it open to recover at least the crystal, for own experiments.
Pics are there:
<
https://www.flickr.com/photos/137684711@N07/49585174873/in/album-72157662535945536/
>
and then following the right arrow.
To get a first impression, I soldered the crystal to an SMA plug and put
it on an
R&S ZVB-8 network analyzer and measured S11. I could see the 5 MHz resonance
as a 15 dB dip. There was also a resonance at 5.45 and a smaller one
another 90 KHz
higher. the +10% suggest that it is an SC cut.
But I could not see anything at 1 or 1.6666 MHz, so it should be a
fundamental crystal?
Is that common?
I made most measurements at room temperature. I can turn the hot air solder
station down to 91°C which is not far away from the crystal's 87.7°C
inflection point, and I could see some variation on the 5.45 MHz
resonance vs. temp.
I must build a fixture for the hot air because the sweep time at 1 Hz
bandwidth
is close to eternal.
Is the un-harmonicity (???) between fundamental and overtones stronger
with SC-cuts
than normal AT? I also could not see anything at 15 MHz. Next I'll make
a board
for the PI fixture as described by Bernd Neubig in his crystal cookbook.
BTW I could see some more dips with >= 10 Hz resolution. I hope that
does not mean
that the ZVB needs service.
cheers, Gerhard
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