[time-nuts] Weird GPSDO behavior
bownes at gmail.com
Fri Sep 29 09:54:17 EDT 2017
How much jitter is there in the 8am number?
If industrial, I could easily see the first shift coming in and all
starting up at about the same time and shutting things off one by one as
the jobs finish. But I would also expect it to not show up on weekends
and/or holidays, etc. Same applies for the theoretical UPS truck w GPS
jammer. And there could be several minutes of jitter.
If it's very precise, that would be more along the lines of a software
More data! :)
On Fri, Sep 29, 2017 at 9:13 AM, Rob Kimberley <robkimberley at btinternet.com>
> I'd go with a power surge as it's so regular at 8AM.
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Skip
> Sent: 28 September 2017 21:18
> To: time-nuts
> Subject: [time-nuts] Weird GPSDO behavior
> Hello Time-Nuts,
> I have a NTGS50AA GPSDO (close cousin to the NTBW50AA and Thunderbolt)
> with the OCXO removed and a SRS PRS-10 rubidium oscillator in its place. I
> have been running Lady Heather 5.0 and have changed the damping, gain, and
> time constant to give me a 20,000 second time constant with a damping of
> .6. I have attached a Lady Heather screen shot of the weird behavior. You
> can see that my GPS antenna is in a very none ideal location (window on the
> west side of the building).
> Once per day (about 8am) something disturbs the system. So, the GPSDO
> spends much of its time recovering and never gives me anywhere near the
> performance that this system is capable of. I would think that it is not
> the PRS-10 as it has no knowledge of time. I would also think that it is
> not the GPS system or receiver, since the GPS constellation repeats twice
> per day.
> Kind of the two things that I am left with are a glitch by the power
> company every morning (there is some large industrial machinery across the
> street (but then I would kind of expect glitches at 8am and 5pm), and
> perhaps Lady Heather doing something funny. This system has been running
> for quite some time, I have not tried restarting Lady Heather yet.
> Anybody seen anything like this, or have any good ideas?
> Thanks in advance,
> Skip Withrow<div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2"><br /> <table
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