[time-nuts] OCXO sensitive to gravity
SAIDJACK at aol.com
SAIDJACK at aol.com
Fri Aug 14 00:14:17 UTC 2009
Hi there,
there are special low-g OCXO's out there. We offer one that has better than
3E-010 per g per axis, which is about 10x better than your "standard"
OCXO.
This is also important for stationary applications where the unit is not
tilted, for vibration-induced phase-noise is also that much smaller with a
low-g OCXO versus a standard OCXO.
bye,
Said
In a message dated 8/13/2009 11:02:51 Pacific Daylight Time,
wpxs472 at gmail.com writes:
A while back there was some discussion about crystal oscillator's changing
frequency due to the effects of gravity. Since I got my Z3801 up and
running
full time, I have been trying to characterize some OCXOs I had picked off
eBay but had no specifications for. I was trying to fine tune one to the
'3801 and noticed that when I picked it up and tilted it to get to the
adjustment , the frequency changed. I started rotating it 90 degrees at at
time and noticed that the frequency changed up or down depending on which
it
was oriented. The change was immediate and quite noticeable. It is nice to
have something as stable as the Z3801 but now I realize all those OCXOs I
thought were so great, aren't. I do see why the rubidium sources are well
liked. They lock in a couple of minutes and that's pretty much it. The ones
I bought off eBay were both off by about 1E-9. It occurred to me that they
probably in equipment where they were locked to GPS and with nothing
connected to the frequency control input, they would naturally be a little
off.
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