The home time-lab
I hope this isn't too far off topic, as this is having a big impact on my testing.
I decided to run an A/B test on one of my GPSDOs: comparing the phase of the two 10MHz output channels. In the middle of the night, there was a long series of 35ns pops in the phase data. Strangely enough, there was nothing in the data collected directly from the unit involved. The preceding two days we had had a number of switching transients where the lights blinked but nothing shut down. So, putting one and one together, I suspect that a fair percentage of the strange results I've been getting has been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even understand enough to waste my money on a bad one. The two big questions seem to be "on-line" and "sine wave". Make that three: can I trust the mfgs claims? Is there something affordable that could run a pair of 5370s and maybe another 50W worth of DUTs for up to an hour or two and not be prey to power-line transients? Or would it be more cost effective to somehow monitor the power line for spikes or phase jumps and blow off tests or cut out the offending data? From time to time we get a thread on power-line nuts. Should I have been paying more attention?
Bob - AE6RV
-----------------------------------------------------------------------------------
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
I recommend rigging up something to operate from storage batteries for the
rest, thus eliminating the power line temporarily.
Jeremy
N6WFO
On Thursday, July 7, 2016, Bob Stewart bob@evoria.net wrote:
I hope this isn't too far off topic, as this is having a big impact on my
testing.
I decided to run an A/B test on one of my GPSDOs: comparing the phase of
the two 10MHz output channels. In the middle of the night, there was a
long series of 35ns pops in the phase data. Strangely enough, there was
nothing in the data collected directly from the unit involved. The
preceding two days we had had a number of switching transients where the
lights blinked but nothing shut down. So, putting one and one together, I
suspect that a fair percentage of the strange results I've been getting has
been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even
understand enough to waste my money on a bad one. The two big questions
seem to be "on-line" and "sine wave". Make that three: can I trust the
mfgs claims? Is there something affordable that could run a pair of 5370s
and maybe another 50W worth of DUTs for up to an hour or two and not be
prey to power-line transients? Or would it be more cost effective to
somehow monitor the power line for spikes or phase jumps and blow off tests
or cut out the offending data? From time to time we get a thread on
power-line nuts. Should I have been paying more attention?
Bob - AE6RV
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
time-nuts mailing list -- time-nuts@febo.com javascript:;
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
--
Sent from Gmail Mobile
1/35ns is about 30MHz. Is there anything in your clock chains that is
ticking at 30MHz, such that a false count or slipped count induced by
inductive disruption, would cause a 35ns phase jump?
Related thread:
https://www.febo.com/pipermail/time-nuts/2016-May/098028.html
Tim N3QE
On Thu, Jul 7, 2016 at 8:44 PM, Bob Stewart bob@evoria.net wrote:
I hope this isn't too far off topic, as this is having a big impact on my
testing.
I decided to run an A/B test on one of my GPSDOs: comparing the phase of
the two 10MHz output channels. In the middle of the night, there was a
long series of 35ns pops in the phase data. Strangely enough, there was
nothing in the data collected directly from the unit involved. The
preceding two days we had had a number of switching transients where the
lights blinked but nothing shut down. So, putting one and one together, I
suspect that a fair percentage of the strange results I've been getting has
been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even
understand enough to waste my money on a bad one. The two big questions
seem to be "on-line" and "sine wave". Make that three: can I trust the
mfgs claims? Is there something affordable that could run a pair of 5370s
and maybe another 50W worth of DUTs for up to an hour or two and not be
prey to power-line transients? Or would it be more cost effective to
somehow monitor the power line for spikes or phase jumps and blow off tests
or cut out the offending data? From time to time we get a thread on
power-line nuts. Should I have been paying more attention?
Bob - AE6RV
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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.
Hi
As has been mentioned a few times before …. the best approach is to run batteries to supply the
gear in question off of DC power. Running everything off of it’s own battery may not be practical if
you have gear that is looking for 12V, 15V, 18V, 24V, 28V, 48V and -12V. The practical answer is
to pick a convenient voltage for the battery stack and derive the rest with switchers. 48V and 24V are
pretty good choices if you want to pick up surplus switchers cheap.
====
If you decide to go the UPS route, don’t bother with anything that does not produce a sine wave
output. Modern power factor corrected stuff is a lot happier with sine waves than with weird looking
semi-square wave stuff.
By far the most expensive gear is the stuff that runs full time. You take the AC line and convert it to DC.
That plus a battery supply the DC to sine wave converter. Everything downstream runs off of the DC to
sine wave converter all the time. Since it always supplies the gear, it needs to be big enough to supply
whatever surge the gear requires. That tends to make them a bit large …
None of the UPS systems take care of all issues. There are things like RFI and ground isolation that
still could be an issue. To get into the next layer of that onion you go with stuff like faraday cages and
fairly big filters.
Lots of choices …. lots of money that could be spent.
Bob
On Jul 7, 2016, at 8:44 PM, Bob Stewart bob@evoria.net wrote:
I hope this isn't too far off topic, as this is having a big impact on my testing.
I decided to run an A/B test on one of my GPSDOs: comparing the phase of the two 10MHz output channels. In the middle of the night, there was a long series of 35ns pops in the phase data. Strangely enough, there was nothing in the data collected directly from the unit involved. The preceding two days we had had a number of switching transients where the lights blinked but nothing shut down. So, putting one and one together, I suspect that a fair percentage of the strange results I've been getting has been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even understand enough to waste my money on a bad one. The two big questions seem to be "on-line" and "sine wave". Make that three: can I trust the mfgs claims? Is there something affordable that could run a pair of 5370s and maybe another 50W worth of DUTs for up to an hour or two and not be prey to power-line transients? Or would it be more cost effective to somehow monitor the power line for spikes or phase jumps and blow off tests or cut out the offending data? From time to time we get a thread on power-line nuts. Should I have been paying more attention?
Bob - AE6RV
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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.
Hi Tim,
I don't see how it could be related to a clock chain in my unit. I'm quite literally running the two outputs from one unit through about a meter of coax each to the 5370. These two outputs are from a single 74HCT365. Pins 12 and 14 of the chip (the inputs) are tied together, and pins 11 and 13 each go through a 50 ohm resistor and a 0.1uF cap to an SMA connector. So, even if the software did something really bad, I don't see how it could cause such a blip in the data. This should be measuring just the hardware, not the software. The other input to the 5370 is the PPS pulse from the LEA-6T on the unit buffered through a M74VHC1GT125, which I use to gate the time sample through the EXT input. The EXT level is at preset. And since I had had a few anomalies days before, I set the A and B channel levels to about midpoint in the active range. I'm using 50 ohms, divide by 10, DC, positive slope on both inputs. I had gotten the same sort of thing days before using preset on all inputs.
By the way, I've seen exactly the same sort of thing on my other 5370. It was one of the reasons I chose to get the "new" one. So, unless it's something inherent to the 5370, it pretty much has to be something external to the test setup. The only thing I can think of is the power grid.
Bob -----------------------------------------------------------------------------------
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Tim Shoppa <tshoppa@gmail.com>
To: Bob Stewart bob@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Thursday, July 7, 2016 8:16 PM
Subject: Re: [time-nuts] The home time-lab
1/35ns is about 30MHz. Is there anything in your clock chains that is ticking at 30MHz, such that a false count or slipped count induced by inductive disruption, would cause a 35ns phase jump?
Related thread: https://www.febo.com/pipermail/time-nuts/2016-May/098028.html
Tim N3QE
On Thu, Jul 7, 2016 at 8:44 PM, Bob Stewart bob@evoria.net wrote:
I hope this isn't too far off topic, as this is having a big impact on my testing.
I decided to run an A/B test on one of my GPSDOs: comparing the phase of the two 10MHz output channels. In the middle of the night, there was a long series of 35ns pops in the phase data. Strangely enough, there was nothing in the data collected directly from the unit involved. The preceding two days we had had a number of switching transients where the lights blinked but nothing shut down. So, putting one and one together, I suspect that a fair percentage of the strange results I've been getting has been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even understand enough to waste my money on a bad one. The two big questions seem to be "on-line" and "sine wave". Make that three: can I trust the mfgs claims? Is there something affordable that could run a pair of 5370s and maybe another 50W worth of DUTs for up to an hour or two and not be prey to power-line transients? Or would it be more cost effective to somehow monitor the power line for spikes or phase jumps and blow off tests or cut out the offending data? From time to time we get a thread on power-line nuts. Should I have been paying more attention?
Bob - AE6RV
-----------------------------------------------------------------------------------
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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.
Tim,
There is one variable that I neglected to mention in the first response. I've been unhappy with the stability of the 10811s in both 5370s. So, for this test, I'm using the 10MHz output from another one of my units to supply the clock. In the past 71,000 seconds of the retest, I'm seeing a phase variance of only +60ps to -80ps in timelab with an "averaging window" of 0.
Bob
-----------------------------------------------------------------------------------
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Tim Shoppa <tshoppa@gmail.com>
To: Bob Stewart bob@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Thursday, July 7, 2016 8:16 PM
Subject: Re: [time-nuts] The home time-lab
1/35ns is about 30MHz. Is there anything in your clock chains that is ticking at 30MHz, such that a false count or slipped count induced by inductive disruption, would cause a 35ns phase jump?
Related thread: https://www.febo.com/pipermail/time-nuts/2016-May/098028.html
Tim N3QE
On Thu, Jul 7, 2016 at 8:44 PM, Bob Stewart bob@evoria.net wrote:
I hope this isn't too far off topic, as this is having a big impact on my testing.
I decided to run an A/B test on one of my GPSDOs: comparing the phase of the two 10MHz output channels. In the middle of the night, there was a long series of 35ns pops in the phase data. Strangely enough, there was nothing in the data collected directly from the unit involved. The preceding two days we had had a number of switching transients where the lights blinked but nothing shut down. So, putting one and one together, I suspect that a fair percentage of the strange results I've been getting has been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even understand enough to waste my money on a bad one. The two big questions seem to be "on-line" and "sine wave". Make that three: can I trust the mfgs claims? Is there something affordable that could run a pair of 5370s and maybe another 50W worth of DUTs for up to an hour or two and not be prey to power-line transients? Or would it be more cost effective to somehow monitor the power line for spikes or phase jumps and blow off tests or cut out the offending data? From time to time we get a thread on power-line nuts. Should I have been paying more attention?
Bob - AE6RV
-----------------------------------------------------------------------------------
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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.
You'd be better off running the GPSDO off a LiFePO battery and float
charge the battery with an appropriately constructed linear PS...
ALL but the most expensive UPSs use switch-mode power supplies... to
power the load when on mains.
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389
On 7/7/2016 7:44 PM, Bob Stewart wrote:
I hope this isn't too far off topic, as this is having a big impact on my testing.
I decided to run an A/B test on one of my GPSDOs: comparing the phase of the two 10MHz output channels. In the middle of the night, there was a long series of 35ns pops in the phase data. Strangely enough, there was nothing in the data collected directly from the unit involved. The preceding two days we had had a number of switching transients where the lights blinked but nothing shut down. So, putting one and one together, I suspect that a fair percentage of the strange results I've been getting has been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even understand enough to waste my money on a bad one. The two big questions seem to be "on-line" and "sine wave". Make that three: can I trust the mfgs claims? Is there something affordable that could run a pair of 5370s and maybe another 50W worth of DUTs for up to an hour or two and not be prey to power-line transients? Or would it be more cost effective to somehow monitor the power line for spikes or phase jumps and blow off tests or cut out the offending data? From time to time we get a thread on power-line nuts. Should I have been paying more attention?
Bob - AE6RV
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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.
Hi
Have you been through the full alignment process on one or both of the 5370’s ? They are as much
an analog beast as they are digital. They do drift out of calibration / alignment / adjustment. When
they go it’s usually not all of a sudden. They just gradually get worse and worse as the adjustments bake
away inside that hot box.
===========
35 ns pops are pretty big. Are you seeing spikes or are you seeing steps? Spikes can be just about
anything, including the next door neighbor’s bug zapper. Steps are a bit more indicative of something
actually wrong. In either case, a counter with far less resolution than a 5370 can be used to help “triangulate”
the problem. A free running OCXO (or three) is also perfect for this sort of thing.
Bob
On Jul 7, 2016, at 10:16 PM, Bob Stewart bob@evoria.net wrote:
Tim,
There is one variable that I neglected to mention in the first response. I've been unhappy with the stability of the 10811s in both 5370s. So, for this test, I'm using the 10MHz output from another one of my units to supply the clock. In the past 71,000 seconds of the retest, I'm seeing a phase variance of only +60ps to -80ps in timelab with an "averaging window" of 0.
Bob
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Tim Shoppa <tshoppa@gmail.com>
To: Bob Stewart bob@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Thursday, July 7, 2016 8:16 PM
Subject: Re: [time-nuts] The home time-lab
1/35ns is about 30MHz. Is there anything in your clock chains that is ticking at 30MHz, such that a false count or slipped count induced by inductive disruption, would cause a 35ns phase jump?
Related thread: https://www.febo.com/pipermail/time-nuts/2016-May/098028.html
Tim N3QE
On Thu, Jul 7, 2016 at 8:44 PM, Bob Stewart bob@evoria.net wrote:
I hope this isn't too far off topic, as this is having a big impact on my testing.
I decided to run an A/B test on one of my GPSDOs: comparing the phase of the two 10MHz output channels. In the middle of the night, there was a long series of 35ns pops in the phase data. Strangely enough, there was nothing in the data collected directly from the unit involved. The preceding two days we had had a number of switching transients where the lights blinked but nothing shut down. So, putting one and one together, I suspect that a fair percentage of the strange results I've been getting has been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even understand enough to waste my money on a bad one. The two big questions seem to be "on-line" and "sine wave". Make that three: can I trust the mfgs claims? Is there something affordable that could run a pair of 5370s and maybe another 50W worth of DUTs for up to an hour or two and not be prey to power-line transients? Or would it be more cost effective to somehow monitor the power line for spikes or phase jumps and blow off tests or cut out the offending data? From time to time we get a thread on power-line nuts. Should I have been paying more attention?
Bob - AE6RV
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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.
Hi Bob,
They're spikes. So, what I'll do is just keep a test like this running for the next few days as I do other things. I'll go ahead and put it back on internal clock, just in case. If I see nothing, I'm going to have to conclude it's the power line. If bad weather comes back and they happen again, once again I have to conclude it's the power line.
I haven't taken the time to go through either unit. I'll try to make some time for that in the next few weeks.
Bob
-----------------------------------------------------------------------------------
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Bob Camp <kb8tq@n1k.org>
To: Bob Stewart bob@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Thursday, July 7, 2016 10:17 PM
Subject: Re: [time-nuts] The home time-lab
Hi
Have you been through the full alignment process on one or both of the 5370’s ? They are as much
an analog beast as they are digital. They do drift out of calibration / alignment / adjustment. When
they go it’s usually not all of a sudden. They just gradually get worse and worse as the adjustments bake
away inside that hot box.
===========
35 ns pops are pretty big. Are you seeing spikes or are you seeing steps? Spikes can be just about
anything, including the next door neighbor’s bug zapper. Steps are a bit more indicative of something
actually wrong. In either case, a counter with far less resolution than a 5370 can be used to help “triangulate”
the problem. A free running OCXO (or three) is also perfect for this sort of thing.
Bob
On Jul 7, 2016, at 10:16 PM, Bob Stewart bob@evoria.net wrote:
Tim,
There is one variable that I neglected to mention in the first response. I've been unhappy with the stability of the 10811s in both 5370s. So, for this test, I'm using the 10MHz output from another one of my units to supply the clock. In the past 71,000 seconds of the retest, I'm seeing a phase variance of only +60ps to -80ps in timelab with an "averaging window" of 0.
Bob
-----------------------------------------------------------------------------------
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Tim Shoppa tshoppa@gmail.com
To: Bob Stewart bob@evoria.net; Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Thursday, July 7, 2016 8:16 PM
Subject: Re: [time-nuts] The home time-lab
1/35ns is about 30MHz. Is there anything in your clock chains that is ticking at 30MHz, such that a false count or slipped count induced by inductive disruption, would cause a 35ns phase jump?
Related thread: https://www.febo.com/pipermail/time-nuts/2016-May/098028.html
Tim N3QE
I have this set up in my radio room with ham radio equipment and my
thunderbolt. I got the same size battery as is in my truck so if that fails,
I have a drop-in replacement.
There is a company in the USA that manufactures a product called
BatteryTender - excellent float charger and maintainer. Costco sells them
for $40
http://www.costco.com/Battery-Tender-Power-Plus-3-Amp-Charger.product.100241
973.html
Dave
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf
Of Jeremy Nichols
Sent: Thursday, July 07, 2016 18:12
To: Bob Stewart; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] The home time-lab
I recommend rigging up something to operate from storage
batteries for the
rest, thus eliminating the power line temporarily.
Jeremy
N6WFO
On Thursday, July 7, 2016, Bob Stewart bob@evoria.net wrote:
I hope this isn't too far off topic, as this is having a
big impact on my
testing.
I decided to run an A/B test on one of my GPSDOs: comparing
the phase of
the two 10MHz output channels. In the middle of the night,
there was a
long series of 35ns pops in the phase data. Strangely
enough, there was
nothing in the data collected directly from the unit involved. The
preceding two days we had had a number of switching
transients where the
lights blinked but nothing shut down. So, putting one and
one together, I
suspect that a fair percentage of the strange results I've
been getting has
been power-grid related.
So, what to do? I've been looking at UPS devices, and I don't even
understand enough to waste my money on a bad one. The two
big questions
seem to be "on-line" and "sine wave". Make that three: can
I trust the
mfgs claims? Is there something affordable that could run
a pair of 5370s
and maybe another 50W worth of DUTs for up to an hour or
two and not be
prey to power-line transients? Or would it be more cost
effective to
somehow monitor the power line for spikes or phase jumps
and blow off tests
or cut out the offending data? From time to time we get a thread on
power-line nuts. Should I have been paying more attention?
Bob - AE6RV
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
time-nuts mailing list -- time-nuts@febo.com javascript:;
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
--
Sent from Gmail Mobile
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.