Topics

WSJT-X Time Sync--Request for Document Change


w6de
 

Dave and group, in this WIKI article:

http://www.dxlabsuite.com/dxlabwiki/GettingStartedwithK1JTModesWithJTAlert

it states:

“If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard, install one and initiate it:

·         Dimension 4

·         Meinberg

·         Net Time

I believe this should be re-written as follows:

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg software and run it.

 

The Meinberg software can be obtained free from: the Meinberg Software Download web site.  On the left side select NTP for Windows.  This will take you to the NTP for Windows XP and Newer, with IPv6 support web page.  Click to download the highlighted ntp #version.exe file.  This file will work for both 32 bit and 64 bit version of Windows.  Note the web site comment below the download regarding Visual Studio Redistributable package.  More information about the Meinberg installation is available further down the web page.  You may select a time server for Meinberg to work with from one of these sources:

https://tf.nist.gov/tf-cgi/servers.cgi

https://timetoolsltd.com/information/public-ntp-server/

The second site provides time server locations WorldWide.

 

The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock; so there are no radical shifts in the clock which can cause issues in processes.  This includes WSJT-X timing (both TX and tone timing). 

W6DE’s comments:  I found out about the tick vs clock Issue with WSJT-X and the Meinberg solution in a discussion with Rick NK7I.  I also believe Joe W4TV has pointed out this issue in the past too.  Although, I didn’t ‘get it’ until my discussion with Rick, NK7I.

 

Dimension 4 and Net Time fail to adjust the ticks. I had previously been using NetTime with my own GPS Disciplined Time Server.  I now use Meinberg synced to my GPS Time Server.

 

Finally, It may be appropriate to write a separate WIKI article about Time, Clocks and Computers for the WIKI instead of  sticking all this into the “Getting Started with K1JTModes With JTAlert” WIKI article.

73,

Dave, w6de

 


Dave AA6YQ
 

+ AA6YQ comments below

Dave and group, in this WIKI article:

http://www.dxlabsuite.com/dxlabwiki/GettingStartedwithK1JTModesWithJTAlert

it states:

“If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard, install one and initiate it:

· Dimension 4 <http://www.thinkman.com/dimension4/download.htm>

· Meinberg <https://www.meinbergglobal.com/english/sw/ntp.htm>

· Net Time <http://www.timesynctool.com/> ”

I believe this should be re-written as follows:

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg software and run it.

The Meinberg software can be obtained free from: the Meinberg Software Download web site. On the left side select NTP for Windows. This will take you to the NTP for Windows XP and Newer, with IPv6 support web page. Click to download the highlighted ntp #version.exe file. This file will work for both 32 bit and 64 bit version of Windows. Note the web site comment below the download regarding Visual Studio Redistributable package. More information about the Meinberg installation is available further down the web page. You may select a time server for Meinberg to work with from one of these sources:

https://tf.nist.gov/tf-cgi/servers.cgi

https://timetoolsltd.com/information/public-ntp-server/

The second site provides time server locations WorldWide.

The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock; so there are no radical shifts in the clock which can cause issues in processes. This includes WSJT-X timing (both TX and tone timing).

W6DE’s comments: I found out about the tick vs clock Issue with WSJT-X and the Meinberg solution in a discussion with Rick NK7I. I also believe Joe W4TV has pointed out this issue in the past too. Although, I didn’t ‘get it’ until my discussion with Rick, NK7I.

Dimension 4 and Net Time fail to adjust the ticks. I had previously been using NetTime with my own GPS Disciplined Time Server. I now use Meinberg synced to my GPS Time Server.

Finally, It may be appropriate to write a separate WIKI article about Time, Clocks and Computers for the WIKI instead of sticking all this into the “Getting Started with K1JTModes With JTAlert” WIKI article.

+ Re "The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock"

+ What is the difference between "the value of the tick" and "the clock"?

73,

Dave, AA6YQ


iain macdonnell - N6ML
 

On Thu, Dec 24, 2020 at 2:57 PM w6de <v8dave@gmail.com> wrote:

Dave and group, in this WIKI article:

http://www.dxlabsuite.com/dxlabwiki/GettingStartedwithK1JTModesWithJTAlert

it states:

“If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard, install one and initiate it:

· Dimension 4

· Meinberg

· Net Time”

I believe this should be re-written as follows:

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg software and run it.



The Meinberg software can be obtained free from: the Meinberg Software Download web site. On the left side select NTP for Windows. This will take you to the NTP for Windows XP and Newer, with IPv6 support web page. Click to download the highlighted ntp #version.exe file. This file will work for both 32 bit and 64 bit version of Windows. Note the web site comment below the download regarding Visual Studio Redistributable package. More information about the Meinberg installation is available further down the web page.
If we're updating that page, it should really refer to the software as
"Meinberg NTP [for Windows]". Meinberg is a company. The NTP software
for Windows is just one of their products.


You may select a time server for Meinberg to work with from one of these sources:

https://tf.nist.gov/tf-cgi/servers.cgi

https://timetoolsltd.com/information/public-ntp-server/

The second site provides time server locations WorldWide.
I would strongly suggest using a server pool
(https://www.ntppool.org/en/), rather than individual servers.
Meinberg NTP supports this. When I install Meinberg NTP, the only
non-default that I specify is to use the US server pool. I then forget
all about NTP, since it "just works", always.

[snip]

Finally, It may be appropriate to write a separate WIKI article about Time, Clocks and Computers for the WIKI instead of sticking all this into the “Getting Started with K1JTModes With JTAlert” WIKI article.
Agreed.

73,

~iain / N6ML


iain macdonnell - N6ML
 

On Thu, Dec 24, 2020 at 5:02 PM Dave AA6YQ <aa6yq@ambersoft.com> wrote:
+ Re "The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock"

+ What is the difference between "the value of the tick" and "the clock"?
https://kb.meinbergglobal.com/kb/time_sync/ntp/ntp_and_windows_history

Other "clock sync" applications may periodically (e.g. once a day, or
hour) set the clock to the correct time, which causes a sudden jump.

73,

~iain / N6ML


Dave AA6YQ
 

+ AA6YQ comments below

On Thu, Dec 24, 2020 at 2:57 PM w6de <v8dave@gmail.com> wrote:

Dave and group, in this WIKI article:

http://www.dxlabsuite.com/dxlabwiki/GettingStartedwithK1JTModesWithJTA
lert

it states:

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard, install one and initiate it:

Dimension 4

Meinberg

Net Time

I believe this should be re-written as follows:

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg software and run it.



The Meinberg software can be obtained free from: the Meinberg Software Download web site. On the left side select NTP for Windows. This will take you to the NTP for Windows XP and Newer, with IPv6 support web page. Click to download the highlighted ntp #version.exe file. This file will work for both 32 bit and 64 bit version of Windows. Note the web site comment below the download regarding Visual Studio Redistributable package. More information about the Meinberg installation is available further down the web page.
If we're updating that page, it should really refer to the software as "Meinberg NTP [for Windows]". Meinberg is a company. The NTP software for Windows is just one of their products.


You may select a time server for Meinberg to work with from one of these sources:

https://tf.nist.gov/tf-cgi/servers.cgi

https://timetoolsltd.com/information/public-ntp-server/

The second site provides time server locations WorldWide.
I would strongly suggest using a server pool (https://www.ntppool.org/en/), rather than individual servers.
Meinberg NTP supports this. When I install Meinberg NTP, the only non-default that I specify is to use the US server pool. I then forget all about NTP, since it "just works", always.

[snip]

Finally, It may be appropriate to write a separate WIKI article about Time, Clocks and Computers for the WIKI instead of sticking all this into the Getting Started with K1JTModes With JTAlert WIKI article.
+ If someone sends me text for a new Wiki article, I will be happy to format it and add it to "Getting Started with DXLab" under your byline(s), and then modify the two "Getting Started with K1JT modes" articles to reference it.

73,

Dave, AA6YQ


g4wjs
 

On 25/12/2020 01:02, Dave AA6YQ wrote:
+ Re "The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock"

+ What is the difference between "the value of the tick" and "the clock"?

73,

Dave, AA6YQ
Hi Dave,

normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.



--
73

Bill

G4WJS.


Dave AA6YQ
 

* AA6YQ comments below

+ Re "The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock"

+ What is the difference between "the value of the tick" and "the clock"?
normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.

* So Meinberg's implementation of the full NTP protocol results in more frequent updates to the computer's clock that only move the clock forward in time, avoiding larger changes or "time reversals" that could prevent correct decoding of time-sensitive protocols like FT8 and FT4. Correct?

* I tried installing Meinberg per the updated instructions. The installer complained that all was not well and instructed me to "check my event log". Wandering into the NTP/bin folder (a time warp back to command line interpreters), I managed to start the NTP server. How does one monitor the server's operation to confirm that it is behaving correctly?

73,

Dave, AA6YQ


g4wjs
 

Hi Dave,

comments in line below.

On 25/12/2020 01:47, Dave AA6YQ wrote:
* AA6YQ comments below

+ Re "The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock"

+ What is the difference between "the value of the tick" and "the clock"?
normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.

* So Meinberg's implementation of the full NTP protocol results in more frequent updates to the computer's clock that only move the clock forward in time, avoiding larger changes or "time reversals" that could prevent correct decoding of time-sensitive protocols like FT8 and FT4. Correct?
Not necessarily. NTP clients should adjust the clock frequency, no the clock value. When starting up an NTP client can be configured to make step adjustments to quickly synchronize the clock with the elected remote time server, after that it will attempt to characterize the system clock drift and allow the clock to free run. If the clock is stable it may turn out that an NTP client will make less adjustments than an SNTP client, either way it will not step the clock backwards nor forwards in normal operations, just adjust the clock frequency.

* I tried installing Meinberg per the updated instructions. The installer complained that all was not well and instructed me to "check my event log". Wandering into the NTP/bin folder (a time warp back to command line interpreters), I managed to start the NTP server. How does one monitor the server's operation to confirm that it is behaving correctly?

When you install the Meinberg NTP Client it should have added a "Quick NTP Status" start menu entry, it shows the current status of the group of time servers selected for synchronization. The line with a '*' prefix is the currently elected server to synchronize with.

Here's a sample output:

Checking current status of NTP service with ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
-time.cloudflare 10.21.8.19       3 u  864 1024  377   18.870   19.749   8.220
-138.68.183.179  217.114.59.3     3 u  863 1024  375   20.199   22.219   5.218
+85.199.214.98   .GPS.            1 u  674 1024  277   20.325   21.871   3.905
-85.199.214.100  .GPS.            1 u  816 1024  377   21.069   22.056   6.667
*mail.classdesig .PPS.            1 u  345  512  377   19.377   12.428   6.712
+raspberrypi.cla .PPS.            1 u  898  512  376   22.690   14.646  10.550

In my case the selected server is my own GPS stratum 0 time server, it is showing my system is estimated as 12.428 milliseconds ahead with a clock jitter estimated at 6.712 milliseconds. This is my laptop on WiFi so synchronization is not as good as it could be with a wired Ethernet connection to the time server. I also have the uk.pool.ntp.org configured to select time servers for when I am away fro my local network.

As an aside, my GPS time server (Raspberry Pi Model 3+ and GPS receiver with PPS output) is a member of the pool.ntp.org service. This service has many contributors around the Globe, the service monitors and grades contributors and only keeps them in the pool while they show consistent and accurate time. Here's the NTP peer status on the time server itself:

pi@raspberrypi:~ $ ntpq -p
     remote                                   refid      st t when poll reach   delay   offset   jitter
=======================================================================================================
*SHM(1)                                  .PPS.            0 l   20   64  377   0.0000  -0.0378   0.0005
-SHM(0)                                  .GPS.           10 l   58   64  377   0.0000 -103.226 108.6767
 uk.pool.ntp.org                         .POOL.          16 p    -   64    0   0.0000   0.0000   0.0019
 wallace                                 .STEP.          16 u    -  68m    0   0.0000   0.0000   0.0019
-time.rdg.uk.as44574.net                 225.250.232.207  3 u  473 1024    1  19.0613   0.1362   0.1744
-ns4.turbodns.co.uk                      90.187.99.165    2 u  126  128  153  23.3696   0.9894   0.3462
+time.cloudflare.com                     10.21.8.19       3 u   33   64  377  17.0019  -0.5259   0.1454
+183.ip-51-89-151.eu                     18.118.244.103   3 u   51   64  377  17.3613   0.4036   0.0892
-ntp1.exa-networks.co.uk                 185.134.196.169  2 u   66  128  137  24.8810  -0.7166   0.4960
-time.cloudflare.com                     10.21.8.19       3 u   92  128  377  17.4720  -0.6846   1.5002

You can see that it is estimated as 37.8 microseconds behind the received GPS PPS clock with a jitter estimated at 0.5 microseconds.


    73,

              Dave, AA6YQ



--
73

Bill

G4WJS.


Joe Subich, W4TV
 

Dave,

My favorite reference on implementing the Meinberg NTP is:
<https://www.satsignal.eu/ntp/setup.html>

Here is the application I use to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>

73,

... Joe, W4TV

On 2020-12-24 8:47 PM, Dave AA6YQ wrote:
* AA6YQ comments below

+ Re "The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock"

+ What is the difference between "the value of the tick" and "the clock"?
normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.
* So Meinberg's implementation of the full NTP protocol results in more frequent updates to the computer's clock that only move the clock forward in time, avoiding larger changes or "time reversals" that could prevent correct decoding of time-sensitive protocols like FT8 and FT4. Correct?
* I tried installing Meinberg per the updated instructions. The installer complained that all was not well and instructed me to "check my event log". Wandering into the NTP/bin folder (a time warp back to command line interpreters), I managed to start the NTP server. How does one monitor the server's operation to confirm that it is behaving correctly?
73,
Dave, AA6YQ


Dave AA6YQ
 

@ more AA6YQ comments below

+ Re "The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock"

+ What is the difference between "the value of the tick" and "the clock"?

normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.

* So Meinberg's implementation of the full NTP protocol results in more frequent updates to the computer's clock that only move the clock forward in time, avoiding larger changes or "time reversals" that could prevent correct decoding of time-sensitive protocols like FT8 and FT4. Correct?

Not necessarily. NTP clients should adjust the clock frequency, no the clock value. When starting up an NTP client can be configured to make step adjustments to quickly synchronize the clock with the elected remote time server, after that it will attempt to characterize the system clock drift and allow the clock to free run. If the clock is stable it may turn out that an NTP client will make less adjustments than an SNTP client, either way it will not step the clock backwards nor forwards in normal operations, just adjust the clock frequency.

@ Thanks, I understand now.

@ When I was designing minicomputers back in the 1970s, we used AC power zero crossings for long-term clock accuracy, since power companies ensured the correct number of zero crossings per day.


* I tried installing Meinberg per the updated instructions. The installer complained that all was not well and instructed me to "check my event log". Wandering into the NTP/bin folder (a time warp back to command line interpreters), I managed to start the NTP server. How does one monitor the server's operation to confirm that it is behaving correctly?

When you install the Meinberg NTP Client it should have added a "Quick NTP Status" start menu entry, it shows the current status of the group of time servers selected for synchronization.


@ It didn't.

The line with a '*' prefix is the currently elected server to synchronize with.

Here's a sample output:

Checking current status of NTP service with ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
-time.cloudflare 10.21.8.19 3 u 864 1024 377 18.870 19.749 8.220
-138.68.183.179 217.114.59.3 3 u 863 1024 375 20.199 22.219 5.218
+85.199.214.98 .GPS. 1 u 674 1024 277 20.325 21.871 3.905
-85.199.214.100 .GPS. 1 u 816 1024 377 21.069 22.056 6.667
*mail.classdesig .PPS. 1 u 345 512 377 19.377 12.428 6.712
+raspberrypi.cla .PPS. 1 u 898 512 376 22.690 14.646 10.550

In my case the selected server is my own GPS stratum 0 time server, it is showing my system is estimated as 12.428 milliseconds ahead with a clock jitter estimated at 6.712 milliseconds. This is my laptop on WiFi so synchronization is not as good as it could be with a wired Ethernet connection to the time server. I also have the uk.pool.ntp.org configured to select time servers for when I am away fro my local network.

@ There's an ntpstatus.bat in the NTP/Bin folder that invokes

ntpq -p,

which displays the above information.

@ Thanks!

73,

Dave, AA6YQ


Dave AA6YQ
 

+ AA6YQ comments below

My favorite reference on implementing the Meinberg NTP is:
<https://www.satsignal.eu/ntp/setup.html>

Here is the application I use to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>


+ Thanks, Joe! The first URL should be referenced by the Wiki article. The second provides the functionality I was expecting to see.

73,

Dave, AA6YQ


CSM\(r\) Gary Huber - AB9M
 

I've been using NTP and BKT Time Sync with a West Mountain Radio USB GPS Module (for those times when the internet link is down or not available) .

I know, belt and suspenders, but it keeps the computer clock in synch.

73, 
Gary ~ AB9M


From: DXLab@groups.io <DXLab@groups.io> on behalf of Joe Subich, W4TV <lists@...>
Sent: Thursday, December 24, 2020 8:31 PM
To: DXLab@groups.io <DXLab@groups.io>
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change
 

Dave,

My favorite reference on implementing the Meinberg NTP is:
   <https://www.satsignal.eu/ntp/setup.html>

Here is the application I use to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>

73,

    ... Joe, W4TV


On 2020-12-24 8:47 PM, Dave AA6YQ wrote:
> * AA6YQ comments below
>
>> + Re "The Meinberg time application sets the internal Windows time mechanism to adjust the value of the tick, not the clock"
>>
>> + What is the difference between "the value of the tick" and "the clock"?
>
> normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.
>
> * So Meinberg's implementation of the full NTP protocol results in more frequent updates to the computer's clock that only move the clock forward in time, avoiding larger changes or "time reversals" that could prevent correct decoding of time-sensitive protocols like FT8 and FT4. Correct?
>
> * I tried installing Meinberg per the updated instructions. The installer complained that all was not well and instructed me to "check my event log". Wandering into the NTP/bin folder (a time warp back to command line interpreters), I managed to start the NTP server. How does one monitor the server's operation to confirm that it is behaving correctly?
>
>      73,
>
>                Dave, AA6YQ
>
>
>
>
>
>






w6de
 

Thank you Iain, Dave, Bill, and Joe.

I will re-write an article strictly about Time, Clocks and Computers for the WIKI including all of your clarifying comments and re-submit it here. It may be tomorrow as I've lost the heater in my Shop/Shack and I'll be working remote.

73,
Dave, w6de

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of Dave AA6YQ
Sent: Friday, December 25, 2020 02:52
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

+ AA6YQ comments below

My favorite reference on implementing the Meinberg NTP is:
<https://www.satsignal.eu/ntp/setup.html>

Here is the application I use to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>


+ Thanks, Joe! The first URL should be referenced by the Wiki article. The second provides the functionality I was expecting to see.

73,

Dave, AA6YQ


w6de
 

An Article for consideration to include in the DXLab WIKI.
---------------------------------------------

Computer: Time, Clocks and Ticks and their effect on K1JT modes—WSJT, WSJTX, et al

Dave, W6DE; Bill, G4WIS; Joe, W4TV

Computer clocks are notorious for drift. You may need to run a time sync process more frequently than the built in Microsoft Windows time service. One of the author’s computers drifts roughly -60 milliseconds every hour. Over several hours of operating the computer’s internal clock will shift more than 1/10 of a second. This is enough to be able to detect (hear) when operating WSJT-X and effect the start timing of WSJT-X exchange.

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg NTP [for Windows] software and run it.
The Meinberg “NTP for Windows XP and newer, with IPv6 support” is available here:
https://www.meinbergglobal.com/english/sw/ntp.htm#ntp_stable
Scroll down until you see download icon.

Joe, W4TV offers these references for the how-to-do-it for getting and running Meinberg NTP for Windows:
W4TV’s favorite reference on implementing the Meinberg NTP is:
<https://www.satsignal.eu/ntp/setup.html>

Here is the application W4TV uses to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>

The Meinberg NTP application sets the Windows time by adjusting the value of the tick, not the clock; so there are no radical shifts in the clock which can cause issues in processes. This includes WSJT-X timing (both TX and tone timing).

Huh? What is the difference between "the value of the tick" and "the clock"?

The following indented paragraphs are a compilation of several explanations from Bill, G4WJS, one of the developers of WSJTX—Thank You Bill:
Dimension 4, Net Time [and Windows time service, and probably others ..ed] are only basic solutions for correcting time. These applications are SNTP [Simple Time Network Protocol] time service clients and as such only adjust the PC time by periodically brute-force stepping of the clock. For many applications that is OK and if your PC keeps reasonably good time without any synchronization you may never see any issue. This is not the case for all users. There are full NTP [Network Time Protocol] implementations that will adjust the rate of the PC clock by characterizing it compared to a reference time servers known to be accurate. As such it is possible for an NTP implementation to guarantee that, after any start up adjustments, the clock is monotonic, which means there are no backward or forwards steps over clock ticks and every tick happens in their implicit order.

Normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.

A monotonic clock is important for real-time audio applications like WSJT-X since discontinuities introduced into sample streams, ultimately caused by clock adjustments, are likely to disrupt decoding of signals.

----------------------END----------------------

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of w6de via groups.io
Sent: Friday, December 25, 2020 22:11
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

Thank you Iain, Dave, Bill, and Joe.

I will re-write an article strictly about Time, Clocks and Computers for the WIKI including all of your clarifying comments and re-submit it here. It may be tomorrow as I've lost the heater in my Shop/Shack and I'll be working remote.

73,
Dave, w6de


iain macdonnell - N6ML
 

A couple of nit-picks:

Bill would probably appreciate his correct callsign; G4WJS :)

I think that this statement:

"The Meinberg NTP application sets the Windows time by adjusting the
value of the tick, not the clock"

might be better stated something like:

"The Meinberg NTP software effects clock accuracy by adjusting the
value of the tick, not by periodically shifting the clock's current
time".

73,

~iain / N6ML

On Sat, Dec 26, 2020 at 3:17 PM w6de <v8dave@gmail.com> wrote:

An Article for consideration to include in the DXLab WIKI.
---------------------------------------------

Computer: Time, Clocks and Ticks and their effect on K1JT modes—WSJT, WSJTX, et al

Dave, W6DE; Bill, G4WIS; Joe, W4TV

Computer clocks are notorious for drift. You may need to run a time sync process more frequently than the built in Microsoft Windows time service. One of the author’s computers drifts roughly -60 milliseconds every hour. Over several hours of operating the computer’s internal clock will shift more than 1/10 of a second. This is enough to be able to detect (hear) when operating WSJT-X and effect the start timing of WSJT-X exchange.

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg NTP [for Windows] software and run it.
The Meinberg “NTP for Windows XP and newer, with IPv6 support” is available here:
https://www.meinbergglobal.com/english/sw/ntp.htm#ntp_stable
Scroll down until you see download icon.

Joe, W4TV offers these references for the how-to-do-it for getting and running Meinberg NTP for Windows:
W4TV’s favorite reference on implementing the Meinberg NTP is:
<https://www.satsignal.eu/ntp/setup.html>

Here is the application W4TV uses to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>

The Meinberg NTP application sets the Windows time by adjusting the value of the tick, not the clock; so there are no radical shifts in the clock which can cause issues in processes. This includes WSJT-X timing (both TX and tone timing).

Huh? What is the difference between "the value of the tick" and "the clock"?

The following indented paragraphs are a compilation of several explanations from Bill, G4WJS, one of the developers of WSJTX—Thank You Bill:
Dimension 4, Net Time [and Windows time service, and probably others ..ed] are only basic solutions for correcting time. These applications are SNTP [Simple Time Network Protocol] time service clients and as such only adjust the PC time by periodically brute-force stepping of the clock. For many applications that is OK and if your PC keeps reasonably good time without any synchronization you may never see any issue. This is not the case for all users. There are full NTP [Network Time Protocol] implementations that will adjust the rate of the PC clock by characterizing it compared to a reference time servers known to be accurate. As such it is possible for an NTP implementation to guarantee that, after any start up adjustments, the clock is monotonic, which means there are no backward or forwards steps over clock ticks and every tick happens in their implicit order.

Normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.

A monotonic clock is important for real-time audio applications like WSJT-X since discontinuities introduced into sample streams, ultimately caused by clock adjustments, are likely to disrupt decoding of signals.

----------------------END----------------------

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of w6de via groups.io
Sent: Friday, December 25, 2020 22:11
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

Thank you Iain, Dave, Bill, and Joe.

I will re-write an article strictly about Time, Clocks and Computers for the WIKI including all of your clarifying comments and re-submit it here. It may be tomorrow as I've lost the heater in my Shop/Shack and I'll be working remote.

73,
Dave, w6de








g4wjs
 

On 26/12/2020 23:17, w6de wrote:
Dimension 4, Net Time [and Windows time service, and probably others ..ed] are only basic solutions for correcting time. These applications are SNTP [Simple Time Network Protocol] time service clients and as such only adjust the PC time by periodically brute-force stepping of the clock.
Hi Dave,

it is not clear to me if the MS Windows W32Time is an SNTP or full NTP implementation. Microsoft claim it is only an SNTP client but the registry parameters for it look very similar to those used by regular NTP clients like Meinberg, the Unix ntpd client, and more recent implementations like chronyd. I suspect that, like chronyd, it is a hybrid that allows faster corrections for systems that are not always connected to a reference time server, that would be useful for portable systems that do not always have a network connection, or are suspended regularly. Either way the default settings for W32Time only check the reference server at large intervals, probably because MS do not wish to invest in and maintain a network of time servers capable of handling the network traffic load that would occur if reference server intervals were low enough to guarantee accurate timekeeping.



--
73

Bill

G4WJS.


Dave AA6YQ
 

Thanks Dave.

It would be nice to explain what a "tick" is, rather than point the reader at another document to discover the meaning of this important concept.

73,

Dave, AA6YQ

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of w6de
Sent: Saturday, December 26, 2020 6:18 PM
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

An Article for consideration to include in the DXLab WIKI.
---------------------------------------------

Computer: Time, Clocks and Ticks and their effect on K1JT modes�WSJT, WSJTX, et al

Dave, W6DE; Bill, G4WIS; Joe, W4TV

Computer clocks are notorious for drift. You may need to run a time sync process more frequently than the built in Microsoft Windows time service. One of the author�s computers drifts roughly -60 milliseconds every hour. Over several hours of operating the computer�s internal clock will shift more than 1/10 of a second. This is enough to be able to detect (hear) when operating WSJT-X and effect the start timing of WSJT-X exchange.

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg NTP [for Windows] software and run it.
The Meinberg �NTP for Windows XP and newer, with IPv6 support� is available here:
https://www.meinbergglobal.com/english/sw/ntp.htm#ntp_stable
Scroll down until you see download icon.

Joe, W4TV offers these references for the how-to-do-it for getting and running Meinberg NTP for Windows:
W4TV�s favorite reference on implementing the Meinberg NTP is:
<https://www.satsignal.eu/ntp/setup.html>

Here is the application W4TV uses to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>

The Meinberg NTP application sets the Windows time by adjusting the value of the tick, not the clock; so there are no radical shifts in the clock which can cause issues in processes. This includes WSJT-X timing (both TX and tone timing).

Huh? What is the difference between "the value of the tick" and "the clock"?

The following indented paragraphs are a compilation of several explanations from Bill, G4WJS, one of the developers of WSJTX�Thank You Bill:
Dimension 4, Net Time [and Windows time service, and probably others ..ed] are only basic solutions for correcting time. These applications are SNTP [Simple Time Network Protocol] time service clients and as such only adjust the PC time by periodically brute-force stepping of the clock. For many applications that is OK and if your PC keeps reasonably good time without any synchronization you may never see any issue. This is not the case for all users. There are full NTP [Network Time Protocol] implementations that will adjust the rate of the PC clock by characterizing it compared to a reference time servers known to be accurate. As such it is possible for an NTP implementation to guarantee that, after any start up adjustments, the clock is monotonic, which means there are no backward or forwards steps over clock ticks and every tick happens in their implicit order.

Normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.

A monotonic clock is important for real-time audio applications like WSJT-X since discontinuities introduced into sample streams, ultimately caused by clock adjustments, are likely to disrupt decoding of signals.

----------------------END----------------------

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of w6de via groups.io
Sent: Friday, December 25, 2020 22:11
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

Thank you Iain, Dave, Bill, and Joe.

I will re-write an article strictly about Time, Clocks and Computers for the WIKI including all of your clarifying comments and re-submit it here. It may be tomorrow as I've lost the heater in my Shop/Shack and I'll be working remote.

73,
Dave, w6de










--
This email has been checked for viruses by AVG.
https://www.avg.com


w6de
 

I deleted the reference to Microsoft's time service. The catch all reference to SNTP time service should suffice for Windows' approach.
Thank you Bill.

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of g4wjs
Sent: Saturday, December 26, 2020 23:58
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

On 26/12/2020 23:17, w6de wrote:
Dimension 4, Net Time [and Windows time service, and probably others ..ed] are only basic solutions for correcting time. These applications are SNTP [Simple Time Network Protocol] time service clients and as such only adjust the PC time by periodically brute-force stepping of the clock.
Hi Dave,

it is not clear to me if the MS Windows W32Time is an SNTP or full NTP
implementation. Microsoft claim it is only an SNTP client but the
registry parameters for it look very similar to those used by regular
NTP clients like Meinberg, the Unix ntpd client, and more recent
implementations like chronyd. I suspect that, like chronyd, it is a
hybrid that allows faster corrections for systems that are not always
connected to a reference time server, that would be useful for portable
systems that do not always have a network connection, or are suspended
regularly. Either way the default settings for W32Time only check the
reference server at large intervals, probably because MS do not wish to
invest in and maintain a network of time servers capable of handling the
network traffic load that would occur if reference server intervals were
low enough to guarantee accurate timekeeping.



--
73

Bill

G4WJS.


w6de
 

Done.

Thanks, Iain.

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of iain macdonnell - N6ML
Sent: Saturday, December 26, 2020 23:44
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

A couple of nit-picks:

Bill would probably appreciate his correct callsign; G4WJS :)

I think that this statement:

"The Meinberg NTP application sets the Windows time by adjusting the
value of the tick, not the clock"

might be better stated something like:

"The Meinberg NTP software effects clock accuracy by adjusting the
value of the tick, not by periodically shifting the clock's current
time".

73,

~iain / N6ML


On Sat, Dec 26, 2020 at 3:17 PM w6de <v8dave@gmail.com> wrote:

An Article for consideration to include in the DXLab WIKI.
---------------------------------------------

Computer: Time, Clocks and Ticks and their effect on K1JT modes—WSJT, WSJTX, et al

Dave, W6DE; Bill, G4WIS; Joe, W4TV

Computer clocks are notorious for drift. You may need to run a time sync process more frequently than the built in Microsoft Windows time service. One of the author’s computers drifts roughly -60 milliseconds every hour. Over several hours of operating the computer’s internal clock will shift more than 1/10 of a second. This is enough to be able to detect (hear) when operating WSJT-X and effect the start timing of WSJT-X exchange.

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg NTP [for Windows] software and run it.
The Meinberg “NTP for Windows XP and newer, with IPv6 support” is available here:
https://www.meinbergglobal.com/english/sw/ntp.htm#ntp_stable
Scroll down until you see download icon.

Joe, W4TV offers these references for the how-to-do-it for getting and running Meinberg NTP for Windows:
W4TV’s favorite reference on implementing the Meinberg NTP is:
<https://www.satsignal.eu/ntp/setup.html>

Here is the application W4TV uses to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>

The Meinberg NTP application sets the Windows time by adjusting the value of the tick, not the clock; so there are no radical shifts in the clock which can cause issues in processes. This includes WSJT-X timing (both TX and tone timing).

Huh? What is the difference between "the value of the tick" and "the clock"?

The following indented paragraphs are a compilation of several explanations from Bill, G4WJS, one of the developers of WSJTX—Thank You Bill:
Dimension 4, Net Time [and Windows time service, and probably others ..ed] are only basic solutions for correcting time. These applications are SNTP [Simple Time Network Protocol] time service clients and as such only adjust the PC time by periodically brute-force stepping of the clock. For many applications that is OK and if your PC keeps reasonably good time without any synchronization you may never see any issue. This is not the case for all users. There are full NTP [Network Time Protocol] implementations that will adjust the rate of the PC clock by characterizing it compared to a reference time servers known to be accurate. As such it is possible for an NTP implementation to guarantee that, after any start up adjustments, the clock is monotonic, which means there are no backward or forwards steps over clock ticks and every tick happens in their implicit order.

Normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.

A monotonic clock is important for real-time audio applications like WSJT-X since discontinuities introduced into sample streams, ultimately caused by clock adjustments, are likely to disrupt decoding of signals.

----------------------END----------------------

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of w6de via groups.io
Sent: Friday, December 25, 2020 22:11
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

Thank you Iain, Dave, Bill, and Joe.

I will re-write an article strictly about Time, Clocks and Computers for the WIKI including all of your clarifying comments and re-submit it here. It may be tomorrow as I've lost the heater in my Shop/Shack and I'll be working remote.

73,
Dave, w6de








w6de
 

I have modified the 'tick' reference as follows:

What is the difference between "the value of the tick" and "the clock"? In keeping time on a computer there are two elements of time to consider: the right now Time displayed on the Clock; and the point at which the Seconds of that time changes. The point in time when the Seconds change is the tick. The interval between Ticks [a second] should not vary in length. This Tick interval and the actual Tick (sometimes called Hack) are extremely important in Communication and Navigation systems.

73,
Dave, w6de

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of Dave AA6YQ
Sent: Sunday, December 27, 2020 00:47
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

Thanks Dave.

It would be nice to explain what a "tick" is, rather than point the reader at another document to discover the meaning of this important concept.

73,

Dave, AA6YQ

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of w6de
Sent: Saturday, December 26, 2020 6:18 PM
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

An Article for consideration to include in the DXLab WIKI.
---------------------------------------------

Computer: Time, Clocks and Ticks and their effect on K1JT modes�WSJT, WSJTX, et al

Dave, W6DE; Bill, G4WIS; Joe, W4TV

Computer clocks are notorious for drift. You may need to run a time sync process more frequently than the built in Microsoft Windows time service. One of the author�s computers drifts roughly -60 milliseconds every hour. Over several hours of operating the computer�s internal clock will shift more than 1/10 of a second. This is enough to be able to detect (hear) when operating WSJT-X and effect the start timing of WSJT-X exchange.

If you aren't already running an application that synchronizes your computer clock with an internet-accessible time standard; download the Meinberg NTP [for Windows] software and run it.
The Meinberg �NTP for Windows XP and newer, with IPv6 support� is available here:
https://www.meinbergglobal.com/english/sw/ntp.htm#ntp_stable
Scroll down until you see download icon.

Joe, W4TV offers these references for the how-to-do-it for getting and running Meinberg NTP for Windows:
W4TV�s favorite reference on implementing the Meinberg NTP is:
<https://www.satsignal.eu/ntp/setup.html>

Here is the application W4TV uses to monitor the NTP server performance:
<https://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm>

The Meinberg NTP application sets the Windows time by adjusting the value of the tick, not the clock; so there are no radical shifts in the clock which can cause issues in processes. This includes WSJT-X timing (both TX and tone timing).

Huh? What is the difference between "the value of the tick" and "the clock"?

The following indented paragraphs are a compilation of several explanations from Bill, G4WJS, one of the developers of WSJTX�Thank You Bill:
Dimension 4, Net Time [and Windows time service, and probably others ..ed] are only basic solutions for correcting time. These applications are SNTP [Simple Time Network Protocol] time service clients and as such only adjust the PC time by periodically brute-force stepping of the clock. For many applications that is OK and if your PC keeps reasonably good time without any synchronization you may never see any issue. This is not the case for all users. There are full NTP [Network Time Protocol] implementations that will adjust the rate of the PC clock by characterizing it compared to a reference time servers known to be accurate. As such it is possible for an NTP implementation to guarantee that, after any start up adjustments, the clock is monotonic, which means there are no backward or forwards steps over clock ticks and every tick happens in their implicit order.

Normally a full implementation of the NTP protocol will slew the system clock frequency to guarantee that the clock is monotonic. SNTP implementations tend to simply step the clock now and again to force time synchronization. Audio streams are synchronized with the system clock, so discontinuities from a non-monotonic clock are likely to cause discontinuities in them.

A monotonic clock is important for real-time audio applications like WSJT-X since discontinuities introduced into sample streams, ultimately caused by clock adjustments, are likely to disrupt decoding of signals.

----------------------END----------------------

-----Original Message-----
From: DXLab@groups.io [mailto:DXLab@groups.io] On Behalf Of w6de via groups.io
Sent: Friday, December 25, 2020 22:11
To: DXLab@groups.io
Subject: Re: [DXLab] WSJT-X Time Sync--Request for Document Change

Thank you Iain, Dave, Bill, and Joe.

I will re-write an article strictly about Time, Clocks and Computers for the WIKI including all of your clarifying comments and re-submit it here. It may be tomorrow as I've lost the heater in my Shop/Shack and I'll be working remote.

73,
Dave, w6de










--
This email has been checked for viruses by AVG.
https://www.avg.com