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Joe,
well maybe the "crystal drift" is not the whole
story... I measured both your Op-32 and QRSS transmissions (nominally on
137477 and 137777 Hz respectively), before and after the OCXO tweak. Opera has
been -0.7 mHz before and is now closer to nominal (~ -0.1 mHz).
However on Nov 9 the QRSS has been only slightly below nominal (-0.17
mHz), and the tweak has moved it up to +0.44 mHz. So the
offset seems to depend on the selected frequency.
I wonder if you are using a binary DDS, which
would be expected to show a frequency-dependent error due to the
finite stepsize (e.g. 10MHz/2^32)? Anyway this won't be a
problem for EbNaut, as long as the offset is known and
constant.
Good luck with the Canadian MF-crossband
activities!
Best
73,
Markus (DF6NM)
Sent: Thursday, November 12, 2015
10:14 PM
Subject: Re: LF: VO1NA
frequency
Hi Markus,
Convinced that the oscillator had
drifted since calibration 2 years ago, I tweaked the DOXCO up 0.05 Hz and was
happy to see the result on your OPDS page.
Thanks for the tips on getting
started on EbNaut. I'll tinker with it and hopefully make some progress.
Our cat seems anxious lately!
73
Joe
On Thu, 12 Nov 2015,
Markus Vester wrote:
Hi Joe,
an interesting change happened last
night: as far as I can see, your frequency has shifted to nominal 137477.000 at
22:45 UT, and appeared to be rather stable thereafter.
...
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