Hi Alan,
I have never seen anything like this before. One unit generates by gating the
1PPS from the receiver with the 10MHz output. The other gates a 1PPS generated
in the PIC with the 10MHz output. So, different methodologies and different
software. And yet, the 5370 saw nothing of consequence. I wish I had been
logging both units, but that wasn't the case.
I really think this was an external event. The only thing that's changed
environmentally is that we've had a couple of cold nights; as in below freezing
(Houston). But why there would be two sets of glitches spaced 4 hours apart, I
can't imagine.
I've changed nothing on the two units, other than to plug a USB cable into the
second one and started logging. So, if there's a problem with either the
hardware or the firmware, then hopefully it'll repeat. If it's not the current
space weather or the ionosphere, then I'm baffled.
I should mention that the phase glitches weren't sudden "pops". I can see the
phase rising fairly rapidly and then the PLL goes to correct it. In fact, the
phase is moving a lot faster than the analog EFC filter would allow for unless
there was a major movement of the DAC. That wasn't the case. Also, I've got
all the GPSDOs on a UPS. We have quite a few power glitches here, and none of
those in the past have gotten through the UPS. Major power glitches usually
reset my computer, and that didn't happen. I would know because the monitoring
windows were all still open, and there are 8 of them plus VirtualBox and
Windows XP running on that. In short, everything was nominal except for the
fact that the phase moved so far.
Hmm, that does maybe call into question the splitter. I've got a GPS Source 4
port splitter, but I've never traced a problem back to that. It gets its power
from the UPS, as well.
Bob
-----------------------------------------------------------------
AE6RV.com
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Alan Melia <alan.me...@btinternet.com>
To: Discussion of precise time and frequency measurement <time-nuts@febo.com>
Sent: Sunday, January 8, 2017 5:56 PM
Subject: Re: [time-nuts] Something odd - ionosphere?
I doubt that was the cause. The stream was high velocity but low density,
The geomagnetic activity has been relatively low with little precipitation.
Th Kp has touched 4 but that is not unusual and what you report seems an
unusual event. NOAA data is more reliable than Spaceweather which tends to
overhype Solar events in my experience. TheDst index has hardly changed over
the last 6 days.
If no one else reports a glitch.....Do you need to look closer to home??
Alan
G3NYK
----- Original Message -----
From: "Graham" <planoph...@aei.ca>
To: <time-nuts@febo.com>
Sent: Sunday, January 08, 2017 10:17 PM
Subject: Re: [time-nuts] Something odd - ionosphere?
>
> *SOLAR WIND SURROUNDS EARTH:*For the fifth day in a row, Earth is
> surrounded by a fast-moving stream of solar wind flowing froma large hole
> <http://spaceweather.com/images2017/03jan17/ch_strip.png?PHPSESSID=qldvtt9u8qamt2b19ncupb86p2>in
>
> the sun's atmosphere. NOAA forecasters say there is a 40% chance of
> G1-class geomagnetic storms on Jan. 8th asbright auroras
> <http://spaceweathergallery.com/aurora_gallery.htm>flicker around the
> Arctic Circle.
>
> http://spaceweather.com/ for further details
>
> cheers, Graham ve3gtc
>
> On 2017-01-08 20:48, Bob Stewart wrote:
>> This morning at about 0400 CST and again at more or less 0800CST, I
>> noticed a number of large phase excursions on one of the GPSDOs I'm
>> testing. It also happened the day before but I didn't notice the time.
>> I am comparing the 1PPS from two separate units on a 5370. On the one
>> unit I was logging, there were 2 or three phase excursions of up to +/-
>> 28ns or so at these times. And yet, the 5370 showed nothing out of the
>> ordinary on the plot of the phase difference between the two units. So
>> that tells me that it happened to both GPSDOs.
>>
>> Did anyone else see anything odd in whatever units you're logging at
>> around this timeframe? Was this likely caused by an ionospheric shift?
>>
>> Unfortunately, I didn't save the data for any of that, as I was only
>> logging one of the units. Now I'm logging both units in question, as
>> well as the Timelab data, and of course it probably won't happen again.
>> Bob
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
