[time-nuts] Re: NTP server source needed

[shouldbe q931]

On Thu, Apr 21, 2022 at 9:23 AM Paul Watts  wrote:
>
> Long time lurker, first time poster.
>
> In the past, I've purchased the LeoNTP server to act as a local time server
> on my work network. Unfortunately, those NTP servers aren't available to
> order.
>
> I'm in need of two - three more NTP servers for various locations.
>
> Do any of you have an alternate NTP server recommendation?
>
> 1. I'd like to keep the price less than $1,000. The Leo's were a great,
> self contained choice at less than $400.
> 2. Support for IPv4 is required and IPv6 is desired. The main shortcoming I
> have with the Leo's is no support for IPv6.
> 3. I'll serve about 150 clients per site from a given NTP server. My NTP
> clients are a combination of Windows and Linux computers along with various
> types of network gear (Cisco, Palo Alto, Aruba, Juniper). The Leo's don't
> even breathe hard at that level.
> 4. No PTP support is required. My timing needs are IT related - log
> consistency, security protocol requirements, etc.
> 4. I'm not interested in building and using something like a Raspberry Pi.
> I'll be sending these to remote sites and don't want to worry about issues
> like memory card failures and the hobbyist feel of many Pi cases and
> cooling options. That's fine for my home but not for work.
> 5. Availability is important.
>
> Any suggestions are welcome.
>
> Thanks,
>
> Paul Watts.
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No connection to them, but these might fit
https://www.mouser.com/ProductDetail/NetBurner/PK70EX-NTP?qs=W62KBPEYc70bWh%252BpZOx83Q%3D%3D
and mouser appear to have stock.

Cheers

Arne
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[time-nuts] Re: GPS Splitter for L1, GNSS, etc?

[shouldbe q931]

On Wed, Jun 2, 2021 at 10:09 AM shouldbe q931  wrote:
>
> On Wed, Jun 2, 2021 at 5:21 AM W7SLS  wrote:
> >
> > Hello,
> >
> > Looking for group wisdom to avoid newbie mistakes with a GPS splitter.
> >
> > For context, I’m a home- not National- or University-Lab.
> > That said, I have a non-zero budget.
> >
> > Today:
> > Antenna
> > 1- CORS RTK GNSS Survey Antenna high gain measurement GNSS GPS 
> > GLONASS BDS <https://www.ebay.com/itm/253786590956>
> > 2 - patch antenna - works really well with Time Hat, even a few 
> > meters way from window
> >
> > Splitter
> > 1 - Symmetricom 58536A
> >
> > Devices
> > 1 - Auction Site GPSDO
> > 2 - Leo Bodnar GPSDO
> > 3 - Time Hat <— wow!  a fan!
> > 4 - (on the way) 2nd Time Hat
> >
> > Site
> > - suburban, forest to the S, hill to the N
> >
> > Challenge:
> >
> > Existing  splitter is L1 only (I think), which blocks the many 
> > newer GPS satellites.
> > With my compromised (for GPS) location, that’s not so good.
> >
> > I need / want a wider band GPS Splitter
> >
> > 1 - some posts talk about removing the bandpass filters in an 
> > existing splitter
> > OK, but (a) it nukes any value of that splitter, and (b) 
> > those filters also eliminate other interference (yes?)
> >
> > 2 - new choices seem to be in the $1000 and way above, outside of 
> > my budget
> >
> > 3 - more interested in ‘ready to use’ than ‘have to add on 
> > bypasses' to power the antenna (e.g., Cable TV splitter)
> >
> > 3 - auction site has numerous options, but I’m not sure how to 
> > 'separate wheat from chaff’
> >
> > LOL, some of you may be the sellers :)
> >
> > several items $500+  <— more than I want to spend
> > several items $30 -   <— I’d rather not get  aTV antenna 
> > splitter and a hobby to make it work
> >
> > 324575653743  GPS Source S14 $175
> >
> > 153359161105  GPS Antenna Splitter GPS/GLONASS L1 GALILEO 
> > E1 BEIDOU B1- FedEx Fast Ship SV1AFN $120
> >
> >
> > Thoughts?   Thanks for the group bandwidth.
> >
> > Scott W7SLS
> >
> > PS:  yes the Symmetricom 58536A will be for sale after I replace it.
> > ___
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> > an email to time-nuts-le...@lists.febo.com
> > To unsubscribe, go to and follow the instructions there.
>

And now for the complete email...

One might consider something like 40252864 combined with Bias Tee
DC blocks such as 124130508678 for all bar one of the receivers, which
is used to power the antenna.

Not a one box solution, but very simple to put together with some SMA
to SMA cables.

Cheers

Arne
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[time-nuts] Re: GPS Splitter for L1, GNSS, etc?

[shouldbe q931]

On Wed, Jun 2, 2021 at 5:21 AM W7SLS  wrote:
>
> Hello,
>
> Looking for group wisdom to avoid newbie mistakes with a GPS splitter.
>
> For context, I’m a home- not National- or University-Lab.
> That said, I have a non-zero budget.
>
> Today:
> Antenna
> 1- CORS RTK GNSS Survey Antenna high gain measurement GNSS GPS 
> GLONASS BDS 
> 2 - patch antenna - works really well with Time Hat, even a few 
> meters way from window
>
> Splitter
> 1 - Symmetricom 58536A
>
> Devices
> 1 - Auction Site GPSDO
> 2 - Leo Bodnar GPSDO
> 3 - Time Hat <— wow!  a fan!
> 4 - (on the way) 2nd Time Hat
>
> Site
> - suburban, forest to the S, hill to the N
>
> Challenge:
>
> Existing  splitter is L1 only (I think), which blocks the many newer 
> GPS satellites.
> With my compromised (for GPS) location, that’s not so good.
>
> I need / want a wider band GPS Splitter
>
> 1 - some posts talk about removing the bandpass filters in an 
> existing splitter
> OK, but (a) it nukes any value of that splitter, and (b) 
> those filters also eliminate other interference (yes?)
>
> 2 - new choices seem to be in the $1000 and way above, outside of my 
> budget
>
> 3 - more interested in ‘ready to use’ than ‘have to add on bypasses' 
> to power the antenna (e.g., Cable TV splitter)
>
> 3 - auction site has numerous options, but I’m not sure how to 
> 'separate wheat from chaff’
>
> LOL, some of you may be the sellers :)
>
> several items $500+  <— more than I want to spend
> several items $30 -   <— I’d rather not get  aTV antenna 
> splitter and a hobby to make it work
>
> 324575653743  GPS Source S14 $175
>
> 153359161105  GPS Antenna Splitter GPS/GLONASS L1 GALILEO E1 
> BEIDOU B1- FedEx Fast Ship SV1AFN $120
>
>
> Thoughts?   Thanks for the group bandwidth.
>
> Scott W7SLS
>
> PS:  yes the Symmetricom 58536A will be for sale after I replace it.
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an 
> email to time-nuts-le...@lists.febo.com
> To unsubscribe, go to and follow the instructions there.

One might consider something like
https://www.ebay.com/itm/40252864 combined with SMA
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[time-nuts] Re: time-nuts Digest, Vol 201, Issue 22

[shouldbe q931]

To disable Windows Updates on a workgroup Windows.

Start > Run > gpedit.msc
Computer Configuration > Administrative Templates > Windows Components
> Windows Update
Open Configure Automatic Updates
Select Disabled, then OK to close

To block feature releases (1803/1909/20h4 etc.) requires editing the
registry directly.

Other methods to prevent Windows Updates include running on an
isolated VLAN/Subnet etc.

I would however suggest that three raspberry Pi4 each with GPS/GPSDO
using PPS over GPIO would consume less power, and have greater overall
stability.

Cheers

On Wed, Apr 14, 2021 at 4:47 PM paul swed  wrote:
>
> Several comments along this line.
> I have also attempted a number of ways to stop the enforced reboots and
> upgrades in win 10.
> I do know win 10 embedded/IOT does allow you to shut upgrades off. But
> getting an embedded license seems challenging in 1 or 2 units. As far as I
> can tell embedded is pretty much full win 10 with a bit more control.
> But all that said this threads has been really good with respect to a small
> ntp server for the home. Almost enough to twist my arm into a linux
> implementation.
> Regards
> Paul
> WB8TSL
>
> On Wed, Apr 14, 2021 at 11:28 AM Russ Ramirez 
> wrote:
>
> > Hi Kevin, I tried this (am a Consultant) but on Windows 10 Enterprise, and
> > it had no effect. That's OK though because I am sick of the cr@p MS and
> > other companies are pulling with these platforms (even though it feeds
> > me:-).
> >
> > I'll be implementing the PPS guidance that Canonical has documented for
> > 20.04 tonight.
> >
> > Russ
> >
> >
> > > Message: 5
> > > Date: Tue, 13 Apr 2021 17:28:53 +
> > > From: Kevin Schuchmann 
> > > Subject: [time-nuts] Re: Replacement of Windows NTP server with Linux
> > > To: Discussion of precise time and frequency measurement
> > > 
> > > Message-ID:  > > OJsl2SwfkcECE75dkZWE5KY3ztyPUzz5GSokE1oP5byKdUwf7I=@
> > protonmail.com
> > > >
> > > Content-Type: text/plain; charset=utf-8
> > >
> > > Russ,
> > >   You could have also just run gpedit.msc (group policy editor) to turn
> > > off the updates/reboots in windows 10.
> > > It comes standard on pro but can be added to home also I believe.
> > >
> > > Kevin
> > >
> > >
> > ___
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> > an email to time-nuts-le...@lists.febo.com
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> >
> ___
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Re: [time-nuts] Thunderbolt E failing

[shouldbe q931]

On Mon, Sep 14, 2020 at 10:36 AM Poul-Henning Kamp  wrote:
>
> 
> Matthias Welwarsky writes:
>
> > > The point is that there is no need to compensate the part while it is
> > > locked.
> >
> > It depends. For short time constants, yes, likely the control loop is able 
> > to
> > follow the temperature-induced drift of the OCXO. But you might want the TC 
> > to
> > be as long as possible.
>
> The word you are looking for here is not "Temperature Coefficient"
> but "Thermal Impedance" (more on this below).
>
> > By following the temperature, you have an additional input that allows
> > the controller to act more quickly to a changing environment. Effectively 
> > this
> > will lead to higher stability of the output.
>
> Only if you first spend months and years measuring all the parameters
> and time constants of the multiphysics model you use, well enough
> to make useful predictions with it.
>
> > Maybe, but a linear approximation is probably better than nothing [...]
>
> No, it is usually worse.
>
> A major part of the trouble is the complex hysteresis-effects when
> the temperture changes direction: The components which warm fast
> also cools fast.
>
> For example:  When the temp goes up you will likely find that your
> DAC warms faster than the XTAL, but when the temp goes down it also
> cools faster than the XTAL.
>
> That means the temperature difference between the DAC and XTAL depends
> on the temperature rising or dropping, so you have to model the tempco
> and temperature of them individually.
>
> > If you look at the attached screenshot - there's roughly 5500 seconds of 
> > data
> > from my GPSDO. At about 2500 seconds the temperature compensation was 
> > engaged.
>
> This is nowhere near enough data to show anything.  Collect a full
> week with/without and we can talk.
>
> In the end, the proof is in your allan-variance, if it improves, you got
> something, if it does not, you wasted your time.
>
>
> The easiest and cheapest way for you to get better results, is to increase
> the thermal impedance between the surroundings and your GPSDO.
>
> That will make the temperature change slower, which also means it
> changes less and therefore your hysteresis effects also get smaller.
>
> Note that "thermal impedance" is not the same as "thermal insulation":
>
> Thermal insulation materials have high thermal resistance and low
> thermal mass, and wrapping your GPSDO in that would just make it
> run hot.
>
> Think of it is a thermal RC filter with a huge resistor and a small
> capacitor.
>
> We want the a low to moderate resistor, so the GPSDO can still dump
> its heat, with a huge capacitor to filter out the changes in
> temperature.
>
> Apart from the entire "get electronics wet" thing, water would have
> been near perfect.

There are alternatives to water...
https://www.3m.co.uk/3M/en_GB/novec-uk/applications/immersion-cooling/

Cheers

Arne

>
> Table-top granite (about 2cm thick) is really great, but not very accessible.
>
> Metals almost conduct heat too well, but a box of 1-5cm thick iron
> plates works great, but pay attention to the weight.
>
> For most of us, concrete is the way to go:
>
> Get three cinderblocks of the kind that looks like a 'H' with two
> horizontal bars.
>
> Put the first cinderblock down on its side.
>
> Put the next cinderblock on top of it in normal orientation.
>
> Put your OCXO into the cavity.
>
> Hack notches in the edge of the cinderblock for the cables.
>
> Put the third cinderblock on top, also on its side.
>
> You have now increased the thermal impedance by almost two orders
> of magnitude, and your PLL will be boored.
>
> If need be, you can make the central cavity more air-tight by
> "sealing" between the cinderblocks with a layer of cloth or
> tissue-paper.
>
> --
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
>
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Re: [time-nuts] eLORAN will be on the air GRI 99600

[shouldbe q931]

On Thu, Aug 6, 2020 at 10:40 PM Bill Notfaded  wrote:
>
> Isn't there also CDMA?  We used a EndRun Technologies system not long ago
> that used a small short antenna that could be located inside and didn't
> need a cable to the roof for a GPS antenna.  This was handy for rooms that
> couldn't have anything penetrate the walls at all.  It was a good reference
> and ntp server we used for years that only used time reference from CDMA
> satellites.
>
> Bill

Unless I have misunderstood, CDMA on an Endrun would be a cellular
receiver, not satellite...

Cheers

Arne

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[time-nuts] measurement and Metrology courses from NPL

[shouldbe q931]

Are currently free

https://www.npl.co.uk/skills-learning/free-e-learning

I have no connection to NPL

Cheers

Arne

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Re: [time-nuts] GPS module recommendation for Pi timing

[shouldbe q931]

On Fri, Mar 13, 2020 at 2:07 PM Brian Lloyd  wrote:
>
> I have an application where I need to synchronize the internal TOD RTC in a
> raspberry pi and need to pick a GPS module. We are building our own
> hardware but still using the Pi so interconnection will be via GPIO/serial.
> We won't try to use USB.
>
> This is not an NTP application. These units will be in the field and will
> most likely not have Internet access. I need their clocks to be pretty
> close. I am shooting for 1ms ... if possible.
>
> The new M9F and M9T modules from Ublox are a bit pricey. The M8T is a bit
> more reasonable. OTOH I realize there are limits to how tightly I can
> control the Pi's RTC and will run into diminishing returns, so even the M8T
> might be overkill.
>
> Has anyone here figured out what the reasonable limit is for timing on a
> Pi, and what makes sense for a timing module for an application like this?
>
> Thanks.
>
> --
>
>
>
> Brian Lloyd
> 706 Flightline
> Spring Branch, TX 78070
> br...@lloyd.aero
> +1.210.802-8FLY (1.210.802-8359)

If you are using a Pi, then you are limited to the Pi onboard crystal,
however as long as the GPS signal is "good", and the temperature is
stable, <1ms should be easily acheivable (my logs show ~20us is) while
GPS is running, however without GPS, the drift can be significant.

Although you might not need external NTP, the "simple" stack would be
ue gpsd to listen to the GPS and PPS, and then ntp/ntpsec/chrony to
set the time.

If you wanted a "plug and play" solution, the uptronics board is the
probably simplest.
https://store.uputronics.com/index.php?route=product/product_id=81,
otherwise for 1ms, there are many suppliers of uBlox modules.

Cheers

Arne

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Re: [time-nuts] Fake new LPRO 101 Rb's on Ebay?

[shouldbe q931]

On Tue, Feb 4, 2020 at 9:17 AM Christoph Kopetzky  wrote:
>
> The seller is located in Israel :) not in China. So the corona would not
> really be the problem.
> But the items are not new(!). The product date code is 06/21/00 for the
> one and 0127 as 27th week of 2001
> is for the second one.
>
> best regards

While there are some for sale in Israel, there are also some in China

I would suggest just searching for "LPRO 101"

Cheers

Arne

>
> Chris
> ---
> 'Everything should be made as simple as possible, but not simpler.' -- Albert 
> Einstein
>
> Am 04.02.2020 um 08:29 schrieb Perry Sandeen via time-nuts:
> > Yo Bubba Dudes!,
> > There are two vendors on Ebay selling *new* LPRO 101 Rb's for around $160 
> > each, with discounts for larger purchases.  The general price of a used 
> > LPRO seems to be in the $250 to $350 range.  Anybody have any ideas?  
> > (Discount for coronavirus?)
> > In all seriousness, can the coronavirus be transmitted in gear we buy from 
> > China or does it require a living host for spreading?
> >
> > Regards,
> > Perrier
> >
> >
> >
> > ___
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> > To unsubscribe, go to 
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>
>
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Re: [time-nuts] Yesterday was the first palindromic date for 909 years

[shouldbe q931]

On Mon, Feb 3, 2020 at 2:05 PM  wrote:
>
> 2021-12-02
> 12-02-2021
>
> I'm afraid the UK is out of that one though and any 20xx year. Sucks to be
> them!
>
> Michael Lee Finney
>
> --
> Best regards,
>  Timenutmailto:time...@metachaos.net
>
The way I read it, 12-02-2021 is the twelfth day of February 2021 in
"UK" date format, a palindromic date

Have I missed something ?

Cheers

Arne

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Re: [time-nuts] Any (relatively) cheap TSIP GPS receivers without WNRO out there?

[shouldbe q931]

On Sun, Jan 12, 2020 at 3:55 AM Skip Withrow  wrote:
>
> I have an NTP server  that uses a Trimble GPS receiver (Accutime 2000,
> p/n - 39091-00, ROM 3.06) that has fallen prey to WNRO.  Just
> wondering if there are any Trimble (or other brand) receivers that
> have TSIP serial comms that are available for a reasonable price?  Any
> help appreciated.
>
> Skip Withrow
>
As TSIP is a Trimble proprietary protocol, to the best of my knowledge
it is only found on Trimble devices.

Does your NTP server only work with TSIP or might it be able to use
"standard" NMEA ? possible with PPS ?

Cheers

Arne

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Re: [time-nuts] Raspberry Pi TCXO Hat

[shouldbe q931]

On Tue, Nov 5, 2019 at 12:03 PM David J Taylor via time-nuts
 wrote:
>
> Folks,
>
> As a matter of interest, I've just compared the reported jitter on a RPi 3B,
> RPi 3B+ and RPi-4B, all PPS synced with classic NTP, all in the same room,
> but with slightly different puck antenna locations.


Have you considered driving multiple Pi from the same PPS source ? And
to keep their
temperature stable, keeping all three in the same enclosure ?

Cheers

Arne

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Re: [time-nuts] Low cost data recording for FA2

[shouldbe q931]

On Wed, Oct 23, 2019 at 2:04 PM ew via time-nuts
 wrote:
>
> From Juerg Koegel
>
> 4$ Openlog
> 6$ Micro SD Card
> 1 hour work
> Bert Kehren___
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Presumably one has to stop logging to access the logged data ?

Cheers

Arne

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Re: [time-nuts] "Deaf" receivers ?

[shouldbe q931]

On Wed, Oct 23, 2019 at 9:20 AM Martin Burnicki
 wrote:
>
> shouldbe q931 wrote:
> > I recently acquired a pair of Meinberg M600's (with GPS-CON downconverters).
>
> Just a summary of what it's for:
>
> Most Meinberg GPS receivers expect an input signal that has been
> down-converted from the original L1 frequency.
>
> The appropriate Meinberg antennae have a built-in down-converter which
> is DC-powered from the receiver, via the antenna cable.
>
> The GPS-CON is an external down-converter that expects an input signal
> from a standard L1 antenna, and outputs a down-converted signal that is
> appropriate for the receiver.
>
> The down-converter itself is powered by the receiver, just like the
> original antenna. The DC power that can be applied to the GPS-CON is
> only forwarded to the 3rd party antenna, whether a voltage is to be
> applied depends on the antenna.
>
> > From the usual auction site got a dual band antenna (for
> > futureproofing), a 2nd hand mini-circuits ZN4PD1-63W-S+, several SMA
> > BIAS-TEE to prevent DC issues, and an assortment of coax cables to
> > connect everything up.
> >
> > To power the antenna I used a ublox M8Q series without a BIAS-TEE
> > connected to the splitter, and then tested with another ublox (a NEO
> > 7M) via a BIAS-TEE that it could also see satellites and that both
> > could get a 3D fix.
> >
> > When I connected up each of the M600's, they eventually acquired
> > positions and acheived sync, but while the ublox receivers rarely do
> > not show a 3d fix, both of the M600's will show the a similar number
> > of satellites in view as the ublox, and sometimes more than one "Good"
> > satellite, but the "Selected Satellite Set:" never seems to change
> > from "00 00 00 00".
>
> When the receiver is powered up and has a good last known position and
> almanac, it expects to be able to track the satellites that should be in
> view at the given location. If those satellites can't be tracked then
> they are kicked out, and the number of good satellites goes down to 0.
>
> Eventually with a few minutes delay, the receiver should enter "Warm
> Boot" mode when this happens. In warm boot mode it tries to track any of
> the 32 possible GPS satellites, and whenever a satellite has been found,
> the number of "good" satellites is increased.

So if I understand you correctly, the number of "Good" satellits, is
the number of tracked satellites ?

>
> If at least 4 satellites can be received, the receiver position is
> determined / verified, and the receiver changes to "Normal Operation" again.
>
> See also the description here:
> https://kb.meinbergglobal.com/kb/meinberg_gps_receivers
>
> > I presume that as its a timing device, that once it has surveyed its
> > position, it only needs one satellite to solve for time, and the MRS
> > status shows "Signal available, Is master, Is locked, Is accurate"
> > with an offset that is usually within -50 to -120ns but I'm lost as to
> > what the "Selected Satellite Set:" should be displaying.
>
> If more tha 4 satellites can be tracked, it should display the 4 main
> satellites that yield the highest accuracy, depending on the constellation.

So if I understand you correctly, the "Selected" part is only filled
in if there are more than four tracked satellites ?

>
> > At the moment, one of the Meinbergs shows 10 in view and one good, and
> > one of the ublox shows 12 in view and 8 used.
>
> This sounds like the input signal is not quite correct, or the device is
> in "Warm Boot" mode where it has just detected a single satellite, but
> is still searching.
>
> A single satellite is enough to keep the time if the stored position is
> known to be the correct one, so the GPS signal propagation can be
> accurately compensated.
>
> If the real position has changed, e.g. because the device has been
> shipped from the previous owner to you, the compensation of the signal
> propagation delay would be wrong if it is based on the previously saved
> receiver position.
>
> This is why the GPS receiver only claims to be fully synchronized if it
> has at temporarily tracked at least 4 satellites, and has verified or
> determined its current geographic position.

Both devices showed their previous location when initially powered on,
I initialised both with cold boot, and both eventually acquired
position, so I would presume that they both managed to acquire 4
satellites during this process.

>
> > I tried with one of the Meinberg's (via the GPS-CON) connected
> > directly to the antenna with no improvement, and tri

[time-nuts] "Deaf" receivers ?

[shouldbe q931]

I recently acquired a pair of Meinberg M600's (with GPS-CON downconverters).

>From the usual auction site got a dual band antenna (for
futureproofing), a 2nd hand mini-circuits ZN4PD1-63W-S+, several SMA
BIAS-TEE to prevent DC issues, and an assortment of coax cables to
connect everything up.

To power the antenna I used a ublox M8Q series without a BIAS-TEE
connected to the splitter, and then tested with another ublox (a NEO
7M) via a BIAS-TEE that it could also see satellites and that both
could get a 3D fix.

When I connected up each of the M600's, they eventually acquired
positions and acheived sync, but while the ublox receivers rarely do
not show a 3d fix, both of the M600's will show the a similar number
of satellites in view as the ublox, and sometimes more than one "Good"
satellite, but the "Selected Satellite Set:" never seems to change
from "00 00 00 00".

I presume that as its a timing device, that once it has surveyed its
position, it only needs one satellite to solve for time, and the MRS
status shows "Signal available, Is master, Is locked, Is accurate"
with an offset that is usually within -50 to -120ns but I'm lost as to
what the "Selected Satellite Set:" should be displaying.

At the moment, one of the Meinbergs shows 10 in view and one good, and
one of the ublox shows 12 in view and 8 used.

I tried with one of the Meinberg's (via the GPS-CON) connected
directly to the antenna with no improvement, and tried with a patch
antenna directly connected, again with no improvement, and different
ports on the splitter etc.

The antenna location is by no means ideal (west facing window in
fairly central London), but none of the ublox receivers (just basic
Max8 and Neo7m, no timing ones yet)  have had any trouble getting and
keeping a 3D fix.

>From my "naive" viewpoint, it looks as if the Meinbergs are a little
"deaf", but I'm guessing that I'm missing something.

Any suggestions gratefully received.

Cheers

Arne

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Re: [time-nuts] HP105B HP 105B 1 amp fuse blowing

[shouldbe q931]

On Fri, Oct 11, 2019 at 10:00 PM Dana Whitlow  wrote:
>
> I once read that Supercapacitors come up short in handling really short
> spikes,
> and that this is not due to physical inductance arising from the
> structure.  Rather,
> the issue was of a subtle (to me) electrochemical nature.
>
> Can anyone either confirm or refute this?  Inquiring minds want to know.
>
> Dana
>

Granted the usage is different, but some time ago most HPE/Dell RAID
controllers moved from using battery (usually NiCad) backed cache
modules, to using flash backed cache with a supercapacitor to power
the transfer from cache to flash.

One would hope that as these are used to protect data integrity, that
HPE and Dell did their homework. I certainly have appreciated no
longer having to replace failed battery packs in servers (-:

Cheers

Arne

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Re: [time-nuts] FA2

[shouldbe q931]

On Thu, Oct 3, 2019 at 12:07 AM Didier Juges  wrote:

> Raspberry Pi has no display, no keyboard.

Yes, the Pi does not have a display or a keyboard, but it does have  USB,
GPIO, Bluetooth WiFi and Ethernet, and separate power.


> If you add those, you far exceed
> the cost of a 7" tablet

Does a device for logging data need a display or a keyboard ?


> and you still have a pile of stuff that barely fits
> in a shoe box let alone in a decent looking enclosure

Without the screen and keyboard you get a _much_ smaller device.


> and that you would
> not want to leave on a table unattended.
> A cheap Android tablet is hard to beat if you need a display and keyboard
> and having played quite a bit with both, my RPis are still all in the same
> box where they came in while a number of Android tablets are used
> throughout the house as remote controls for a number of things.
> The most recent is a$49 7" Fire tablet to use also as a controller. Nice
> piece of hardware for the cost.
>
As something to control other things, an Android tablet (or phone with
WiFi) is very good, I also have several, but for datalogging (temperature,
humidity, ADS-B etc), or for providing network access to a device that has
serial or USB management interfaces, I use an rPi without screen or
keyboard, all bar one have have never had a screen or keyboard connected to
them.

People have a tendancy to pick up tablets, when a single USB (mini/micro/C)
cable is used for data collection as well as power, I would be concerned
that the cable might be unplugged, with something like a rPi, there is no
requirement to move the rPi, but one could certainly use a tablet to access
the data that has been logged.

Different horses for different courses (-:


> Writing Android apps using a tool like B4A is a lot of fun, with a Visual
> Studio like environment.
>
> Of course, if you need a lot of discrete IOs, the RPi is very handy.
>
> Didier KO4BB
>
> On Wed, Oct 2, 2019, 12:00 PM shouldbe q931 
> wrote:
>
> > On Wed, Oct 2, 2019 at 4:00 PM ew via time-nuts <
> time-nuts@lists.febo.com>
> > wrote:
> >
> > > Good Morning DidierThank you for your response. The "ONLY" thing we
> would
> > > like to do is record and display the info coming out of the RS post. To
> > day
> > > making long term observations ties up a PC or Laptop with fans and a
> > > HP53132. Gone for a week the main concern is fan failure. Store the
> info
> > on
> > > the Tablet in a SD chip or in it and when ready download through the
> USB
> > > port that we use for importing data to a memory stick for further
> > processing
> > >
> > 
> >
> > Rather than a tablet, might I be so bold as suggesting using a fanless
> PC,
> > such as a RaspberryPi (other small fanless computers are available).
>
> Cheers

Arne
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Re: [time-nuts] FA2

[shouldbe q931]

On Wed, Oct 2, 2019 at 4:00 PM ew via time-nuts 
wrote:

> Good Morning DidierThank you for your response. The "ONLY" thing we would
> like to do is record and display the info coming out of the RS post. To day
> making long term observations ties up a PC or Laptop with fans and a
> HP53132. Gone for a week the main concern is fan failure. Store the info on
> the Tablet in a SD chip or in it and when ready download through the USB
> port that we use for importing data to a memory stick for further processing
>


Rather than a tablet, might I be so bold as suggesting using a fanless PC,
such as a RaspberryPi (other small fanless computers are available).

Cheers

Arne
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Re: [time-nuts] Precision Time Protocol – Windows 10 implementation

[shouldbe q931]

On Thu, Aug 8, 2019 at 4:07 PM Adam Kumiszcza  wrote:

> Hi everybody! My first post here, I hope the subject is adequate for this
> mailing list.
>
> I'm using a tiny layer 1 NTP server consisting of Raspberry Pi 3B+ with
> Ublox MAX-M8Q expansion board providing GNSS (currently GPS, Galileo and
> Glonass, sometimes I switch to Beidou, too) reference with PPS + a simple
> patch antenna hanging near the window. Offset, jitter and rms are most
> often smaller than 1 µs. The server is included in NTP pool.
>
> I'm using several Windows 10 machines on the same LAN, all using NTP client
> software from Meinberg. The typical offset and jitter in those are about
> 100-500 µs. I would like to make it lower. I've heard that one of the
> latest versions of Windows 10 provides support for PTP protocol (IEEE
> 1588v2). Hence my questions:
>
> 1. Did anybody try using it on Windows 10 already? From what I can tell
> right now, there's only a demonstration web site showing it works when
> using Ubuntu Linux as a virtual machine [1]. Or should I wait a bit for
> more robust implementation?
> 2. Do I guess correctly that current implementation of PTP works only on
> Ethernet? Some of the computers are on wlan.
> 3. Is there any other way of making the clients' time offset lower?
>

Although there is one method using WSL, there is also the "native" method
https://techcommunity.microsoft.com/t5/Networking-Blog/Top-10-Networking-Features-in-Windows-Server-2019-10-Accurate/ba-p/339739
"Precision Time Protocol - Try it out!"

PTP can be used across any IP network, but if there is non deterministic
latency (jitter), there is a fairly obvious effect.

The offset should reduce over time, but jitter will affect this.

I've already tried setting PTP on the Raspberry Pi 3B+. It needed a kernel
> recompilation with a patch I found here: [2], but I'm not sure it works
> correctly.
>

I have run PTP on a rPi 3B without any kernel modifications as a
grandmaster (with a ublox GPS to provide time and PPS), and experimented
with different NICs (intel, broadcom and solarflare, all with HW
timestamping) as clients in x64 hosts.

There are two issues with using a rPi as a PTP grandmaster, the crystal is
"not very stable", and the NIC is connected over USB, both of these add
jitter which is noticeable on PTP. The jjitter is obvious when compared to
a meinberg m600 with the HQ OXCO option.connected to a Solarflare NIC in a
Linux host.

To remove the jitter issues, you might care to try the ublox connected (via
a suitable level converter for NMEA and PPS) to a hardware serial port on a
Linux X64 host.

I have not tried the native Windows PTP client, there are also 3rd party
clients from greyware and fsmlabs.


> As you can see on the screenshot below, PTP appears here as a server, but
> I'm not sure if it's used at all.
> [image: status16.PNG]
>
> Ptp4l status shows this:
>
> pi@zegar:~ $ systemctl status ptp4l
> ● ptp4l.service - Precision Time Protocol (PTP) service
>Loaded: loaded (/lib/systemd/system/ptp4l.service; enabled; vendor
> preset: enabled)
>Active: active (running) since Wed 2019-08-07 12:32:28 CEST; 24h ago
>  Docs: man:ptp4l
>  Main PID: 323 (ptp4l)
> Tasks: 1 (limit: 4915)
>CGroup: /system.slice/ptp4l.service
>└─323 /usr/sbin/ptp4l -f /etc/linuxptp/ptp4l.conf -i eth0
>
> Aug 07 12:32:31 zegar ptp4l[323]: ptp4l[6.631]: port 1: link up
> Aug 07 12:32:31 zegar ptp4l[323]: ptp4l[6.631]: port 1: FAULTY to LISTENING
> on FAULT_CLEARED
> Aug 07 12:32:31 zegar ptp4l[323]: [6.631] port 1: link up
> Aug 07 12:32:31 zegar ptp4l[323]: [6.631] port 1: FAULTY to LISTENING on
> FAULT_CLEARED
> Aug 07 12:32:38 zegar ptp4l[323]: ptp4l[13.526]: port 1: LISTENING to
> MASTER on ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES
> Aug 07 12:32:38 zegar ptp4l[323]: ptp4l[13.526]: selected best master clock
> b827eb.fffe.006e65
> Aug 07 12:32:38 zegar ptp4l[323]: ptp4l[13.526]: assuming the grand master
> role
> Aug 07 12:32:38 zegar ptp4l[323]: [13.526] port 1: LISTENING to MASTER on
> ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES
> Aug 07 12:32:38 zegar ptp4l[323]: [13.526] selected best master clock
> b827eb.fffe.006e65
> Aug 07 12:32:38 zegar ptp4l[323]: [13.526] assuming the grand master role
>
> Thanks in advance for any suggestions!
>
> Adam Kumiszcza
>
> [1]
>
> https://techcommunity.microsoft.com/t5/Networking-Blog/Windows-Subsystem-for-Linux-for-testing-Windows-10-PTP-Client/ba-p/389181
> [2] https://github.com/twteamware/raspberrypi-ptp/issues/2
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[time-nuts] Delayed WNRO ?

[shouldbe q931]

Hi All,

According to  https://support.apple.com/en-us/HT210239 Apple devices will
only be affected by the 2019-04-06 WNRO on 2019-11-03.

I wonder if there other devices out there that also have "delayed action"
issues from WNRO.

Cheers

Arne
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Re: [time-nuts] Most popular NMEA sentence with date and time?

[shouldbe q931]

On Mon, Jul 22, 2019 at 9:02 PM David Van Horn via time-nuts <
time-nuts@lists.febo.com> wrote:

> I'm helping a friend with a hobby project, a "Countdown To Christmas"
> clock.
> I haven't looked at the NMEA docs in a while or three..  What's the most
> widely supported sentence(s) that will give me date and time?
>
> We're doing one Arduino to grab the data from GPS and talk to the others,
> which each drive one digit of the display selectable by straps so that all
> the digits will be identical except for their strap settings.
>
> --
> David VanHorn
> Lead Hardware Engineer
>

There is a NMEA reference here https://gpsd.gitlab.io/gpsd/NMEA.html

Cheers

Arne
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Re: [time-nuts] Noob question, NTP stratum 1.

[shouldbe q931]

On Mon, Jul 22, 2019 at 5:03 PM wildylion via time-nuts <
time-nuts@lists.febo.com> wrote:

> Yeah, of course I will NOT do anything home-grown for the datacenter.
>
> But currently it uses 3 Stratum 2 NTP servers, one per DC, with them
> referencing a list of 4 close-by Stratum 1 sources.
>
> ntpstat generally says that time is correct within ~50 ms, while jitter
> and offset generally don't exceed 1ms, the root dispersion is quite large.
> Also these Stratum 2 NTPs are run from Cisco routers, which I doubt are
> very good at timekeeping.
>
> When I implemented this scheme, I offered to have S2 on a set of x86
> servers, but was overruled by management who said it'll be better if we run
> S2's off Cisco gear.
>
While one can run most Cisco routers as NTP servers, I would advise against
doing this as they don't have very good clocks, and it adds to the
management plane load.


> So what if we add a couple GPSDO's into the mix, using them as primary
> time sources alongside public Stratum1 NTP servers for sanity check? And of
> course moving the S2's to something more stable.
>
Moving away from the Cisco routers would be my first step.


> My own, homegrown S1 pool NTP is another matter entirely - I think just a
> tuned Raspi with a M8N will be enough?
>
A Pi with a ublox is great fun, unfortunately the clock on the Pi is
"poor", and this is a limiting factor.
https://www.ntpsec.org/white-papers/stratum-1-microserver-howto/

Cheers

Arne
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Re: [time-nuts] Cloudflare

[shouldbe q931]

On Sat, Jun 22, 2019 at 6:00 AM Bob Bownes  wrote:

>
> Most of the good data centers I’ve used either offer a connection to a
> stratum 1 server or are more than happy to put a antenna on the roof. Many
> offer microwave as a third redundant circuit path, which requires an
> antenna. All for a price, of course.
>
> When I worked for an ILEC, many moons ago, we had two and a half floors at
> 60 Hudson St. Our stratum 1 antenna was literally glued to a window. Next
> to a 10GHz dish. :)
>
> My hotel in Toronto two weeks ago overlooked a building that was clearly
> someone’s data center, based on the 6 generators, massive AC, numerous
> microwave links, and yes, GPS bullet antennas, covering the roof.
>
> Bob
>

Because of MIFID II etc. some datacenters are now providing traceable time
services
https://www.npl.co.uk/products-services/time-frequency/npltime/npl-ubs-whitepaper
(NPL is the UK equiv of NIST in the US)

As others have said, to get a cross connect is one thing, to get roof
access is another.

Cheers

Arne
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Re: [time-nuts] how to feed multiple GPS receivers ?

[shouldbe q931]

Hi Bob,  and others that responded off list.

On Mon, Feb 25, 2019 at 2:15 PM Bob kb8tq  wrote:
>
> Hi
>
> On a GPS distribution system the issue of 75 vs 50 ohm cable is pretty
much a
> non-issue. A lot of people have run 75 ohms (like Trimble on the TBolt)
and had
> no problems from this.

This is what I thought, thanks for the confirmation.

> The “TV” splitters are generally spec’d to 2 GHz, so well beyond GPS
frequencies.
> Again, it should not be an issue. There are also cheap multi-port
splitters on the
> auction sites.

Some hints on what to search for would be appreciated.

> DC blocks *are* a good idea. DC loads may or may not be needed. It’s a
try it and see
> sort of thing. Some have been known to simply drop a 50 ohm load on one
port of a
> 8 way splitter and let that be the DC load. You *can* run into issues
doing this ….
> (one device feeds 12V and another is a 3.3V feed …. smoke results …).
Cable TV
> DC blocks are dirt cheap ….

Some DC blocks have been ordered.

> Ideally you want the antenna as high as you can get it. In an urban area
with various
> constraints, that may or may not be very high. Coax losses plus splitter
losses should
> be considered when designing something like this. An amplifier ahead of
the splitter
> is not at all unusual.

To begin with I'm just going to use one of the "puck" antennas in the
window that it is currently in, at which point I'm expecting to discover
that the loss through the TV splitter means that more gain will be
required, or a lower loss splitter.

> With the arrival of world of low cost multi-band GPS devices … put up a
multi-band
> antenna. At the very least L1 / L2 (including Glonass coverage). Ideally
L1 / L2 / L5.
> Much easier to do it right the first time.

The longer term plan is to get a L1/L2 (and possibly L5) antenna and roof
mount it, but stage one is just to get the same feed to the different
receivers.

> Bob

While I'm moderately good at fitting most connectors onto cables, making a
wilkinson splitter PCB or managing to cut coax to exactly the right length
do make on out of co-ax its a little bit beyond what I can get away with in
the workshop kitchen.

Cheers

Arne
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[time-nuts] how to feed multiple GPS receivers ?

[shouldbe q931]

After starting off with a single GPS module on a RaspberryPi, and
discovering the issues of just having a single clock... I now have
three GPS receivers (and a fourth on the way) of various types, each
with their own antenna. I'm aware that I'm heading off down an
interesting road that will consume ever more of my time, but at the
moment it's still fun (-:

To remove the difference of multiple antennas (different skyviews
etc), I'm thinking about using a single antenna and "distributing" the
feed to the receivers.

I should also add that I'm doing this in the UK (in central London),
and as inexpensively as possible.

Reading back through the mailing list several people appear to have
used SatTV splitters with GPS signals to apparently good results, and
I've ordered one of these
https://vision-products.co.uk/8-way-single-port-dc-pass-splitter/
which if I understand it correctly, will passthrough DC from one port,
and block DC from the other ports. From other reading of the mailing
list, it looks as if I will also need to present a DC load to the
other receivers, and if I've read corectly this would be a "Bias tee"
used with a resitive load instead of a DC voltage, but am not sure if
I have understood correctly.

I'm aware of impedance matching issues with using a mix of 75 ohm and
50 ohm parts, but as I said, I'm doing this as inexpensively as
possible, and a 58536A is way over budget at the moment.

Any suggestions gratefully received.

Cheers

Arne

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Re: [time-nuts] time-nuts humor

[shouldbe q931]

On Wed, Sep 19, 2018 at 1:48 AM Eric Scace  wrote:
>
> For a good time, call 303-499-7111
>
> (Sorry! My girlfriend made me do this.)

In the UK, the number used to be 123, which was quite pleasing when I
discovered ntp.

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Re: [time-nuts] Fwd: Re: law and regulation applying to time.. was Re: OOPS on my wwv legal post

[shouldbe q931]

On Fri, Aug 31, 2018 at 10:31 AM Dr. Götz Romahn  wrote:
>
> For German regulations see here:
> https://www.ptb.de/cms/en/ptb/fachabteilungen/abt4/fb-44/ag-442/dissemination-of-legal-time.html
> Götz
>
CET is derived from UTC

https://www.ptb.de/cms/en/ptb/fachabteilungen/abt4/fb-44/ag-441/realisation-of-legal-time-in-germany.html

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Re: [time-nuts] law and regulation applying to time.. was Re: OOPS on my wwv legal post

[shouldbe q931]

On Thu, Aug 30, 2018 at 2:03 PM jimlux  wrote:
>
> On 8/29/18 6:55 PM, John Hawkinson wrote:
> > Continuing reference to what is "legal" or "the law" is very confusing to 
> > me because no one has cited any statues, regulations, or case law.
> >
> > What's the basis for these claims about legal requirement? Can we please 
> > cite chapter and verse? Without it, it's hard to distinguish rumor and 
> > anecdote from fact, or refute anything.
> >
> >
>
> This is an interesting point - a year or so ago (probably around the
> time of the last leap second) there was all this stuff about UTC and
> leap seconds vis a vis electronic trading
>
> There's a internationally agreed second (defined by vibrations of Cs,
> etc.), and I assume that "standard practice" is that everyone adopts
> this rate.
>
As I have read it, the "law" regarding time is about when "something"
happened, and as the "something" is usually between two parties an
external standard needs to be used, so although the second is defined
by the number of transition between the two hyperfine ground states of
caesium, UTC is used as the "standard" and so even though a trading
entity may have a Cs "clock" it would only be used as a holdover
device if time from a directly continuously traceable (to UTC) was
unavailable.
>
> But is it a legal or regulatory *requirement* - or is it just standard
> practice, in the same sense that everyone uses the same M2 or 6-32
> threads.  There's no *law* that requires me to use a particular pipe
> thread or resistor color code. There's a standard that has been
> promulgated for these things, and if I buy, and you sell, it's to our
> mutual advantage to use the same standard.
>
As above the "law" usually relates to UTC rather than how you derive a second.
>
> But if wanted to be "different", (say I was hand crafting English sports
> cars :), I could use a completely different series of fasteners and
> standard dimensions, and I could even use the positive terminal of the
> battery as the chassis common.
>
While it would be possible to build using a different thread to
Whitworth https://en.wikipedia.org/wiki/British_Standard_Whitworth or
metric, having to make every single nut and bolt would be a
considerable overhead.

OT (very) I learnt to drive in a positive earth Morris Minor, and that
was only a "few" decades ago (-:
>
> But is there some International banking agreement that requires UTC? Or
> a SEC rule?
>
MIFID II is a European (not quite International, but when one
considers the reach, it is effectively International) law that
specifically names UTC and tracebility
http://ec.europa.eu/finance/docs/level-2-measures/mifid-rts-25_en.pdf
>
> I buy lots of things that have requirements that say, in effect
> "calibration shall be traceable to NIST or other National Standards
> Lab", but that's a *contractual* requirement, not a *legal* requirement.
>
> There may well be a law in the United States, probably buried in some
> enabling or appropriating bill, that says "The Department of Commerce
> shall provide national standards for mass, time, voltage, etc."  but
> that doesn't say "and all residents of the United States shall use only
> the standard provided by the Department of Commerce, and no other"
>
> What about Germany? Notoriously it is "Das Land der Gebote, der
> Vorschriften, und der Verbote."  (Commandments, regulations, and
> prohibitions)
>
Germany uses UTC
>

Cheers

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