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WSJTX-FT-8 Clock Synchronization

Arvind MallyaArvind Mallya Member ✭✭
I will appreciate if someone can explain the Clock Synchronization for WSJTX-FT-8. It has been hit or miss on QSOs and I checked the CPU utilization which is about 25%. In Windows 10 I set the clock to NIST and found I got fewer QSOs, the Windows display clock and the FT-8 incomming QSOs were off by 13 seconds. When I switched to the Microsoft clock it was much better and was able to complete a QSO in South America. What I would like to know is how does some of the other suggested clocks help improve the synchronization? I would expect all of them have a reference to NIST or some other standard atomic clock standard. image
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Answers

  • Mark NS9NMark NS9N Member
    edited March 2019
    Go to the FT8 web site and there is a link to synchronize your clock. Click on it and all should be good.
  • Dwayne_AB6ADwayne_AB6A Member ✭✭
    edited May 2019
    In comparison to Linux and MacOS, Windows is awful at maintaining time. Your sources are fine, the issue is the frequency of updates. I updated my own system to update every 1800 seconds / 30 minutes... Check out the following articles on how to tweak time update frequency...

    https://timetoolsltd.com/time-sync/how-to-synchronize-microsoft-windows-to-a-ntp-server/

    This second link validates all your processes...
    https://www.thewindowsclub.com/windows-10-clock-time-wrong-fix


  • Tom WorthingtonTom Worthington Member ✭✭
    edited March 2019
    All of those sources depend on your internet connection.  If you have long and uneven delays the corrections can be in error.  I use a GPS receiver and NMEATime to keep my computer synced.
    I started doing this for Field Day since we don't have an internet connection at our (KH6RS) site.
    73 and Aloha, Tom, NH6Y
  • edited March 2019
    An important idea in FT8 is that everyone all over the world starts each 15 second FT8 frame at very nearly the same UTC time, every 15 seconds after the minute.  WSJTx takes its time from your PC clock.  So if your PC is synchronized to UTC (within about 1 second) and so is everyone else's, all our FT8 frames will start at about the same time.

    There are utilities that periodically (every 10 minutes or so) synchronize your PC clock to UTC to within a fraction of a second using data from network time servers.  The utility I use is Dimension4 (so called since time is the fourth dimension).  It works well and doesn't need much setup.  It starts up automatically and you hardly every need to think about it.  

    One nice thing about using a Flex for FT8 is that you can see the signals from other stations on the panadapter as they all startup and shut down each 15 second frame.  You can look at the green bar at the bottom WSJTx (which is based on your PC clock) and see if it starts and finishes at the same time as the signals on the panadapter.

    Good luck with this.

    73,
    Sterling, AK1K

  • Craig_KØCFCraig_KØCF Member ✭✭
    edited June 6
    The recommended method for keeping your computer clock accurate is to download and install the Meinberg NTP Software, available here: https://www.meinbergglobal.com/english/sw/ntp.htm
    Install and run this software and it will keep your clock within milliseconds of the true time. There is virtually no overhead in running this software. You can also check your clock at this site: https://time.is/

    For further information on this, please see the ZL2IFB FT8 Operating Guide at:
    http://www.g4ifb.com/FT8_Hinson_tips_for_HF_DXers.pdf
    Gary has produced an excellent guide to all things FT-8.

  • Justin_KL2DJustin_KL2D Member ✭✭
    edited March 2019
    Meinberg does work great, and if you want to be independent from the internet then check out this small easy to use NTP server: https://timemachinescorp.com/producttimeservers/ I use this with an outside mounted GPS antenna and it keeps everything on my network squared away. I set a static IP on my intranet and pointed meinberg at it, no worries after that. Justin KL2D
  • N8AUMN8AUM RETIRED Member ✭✭
    edited March 2019
    I had similar situation with my little old i5 laptop & Wimblows 10 when I had WSJT set for "DEEP" in the decode menu, it took over 10 seconds to do all the decodes and obviously too late to respond or do anything. Looking at ur screenshot, I see no major time issues with ur "DT". Something else might be causing way too much latency ? my old i7 running Winblows 7 usually sits at 20% cpu usage and I usually have at least 20 tabs open and stream Netflix and have "deep" decode enabled running SSDR on the 6600 and PowersSDR on my 5000 

    gud luck, N8AUM
  • Craig_KØCFCraig_KØCF Member ✭✭
    edited March 2019
    Meinberg NTP is free. And once installed, you don't need to remember to re-sync your clock. Meinberg just sits in the background keeping your clock as close to perfect as is possible. It does not make periodic large corrections to the time, which can upset WSJT-X, but rather adjusts the clock frequency in your PC to maintain the correct time.
  • John - AF3KJohn - AF3K Member
    edited March 2019
    Craig - Completely agree!  I use Meinberg NTP too and love it.  Whenever I use https://time.is/ for a sanity check it always says "Your time is exact!"
  • Neil D Friedman N3DFNeil D Friedman N3DF Member ✭✭
    edited March 2019
    Don't understand how it works (probably magic), but downloaded Meinberg the same day I downloaded WSJT-X (about a year ago) and have never had a time synch problem.  
  • Geoff AB6BTGeoff AB6BT Member ✭✭
    edited March 2019
    Likewise! Meinberg should be used with WSJT-X. No ifs, ands, or buts!!!

    (OK, maybe one if...If you have no Internet then a stable, accurate external time source...)
  • Ted  VE3TRQTed VE3TRQ Member ✭✭
    edited March 2019
    If you don’t mind spending the few dollars it takes to buy NMEATime, and have an old serial or Bluetooth GPS receiver lying around (funny enough, I had two :-), you can take your PC out in the field, nowhere near an Internet connection, and have perfect time. You spent lots of money on a great radio, and a decent amount on a PC that works - do your digital mode apps a favour and have accurate time.
  • Dwayne_AB6ADwayne_AB6A Member ✭✭
    edited May 2019
    Here's a little project for everyone... http://www.dxatlas.com/ToyNtp/ The Garmin 18x which has time sync capabilities is $85.
  • Arvind MallyaArvind Mallya Member ✭✭
    edited March 2019
    So Meinberg still synchs to some reference clock like NIST? Windows 10 already has that option. So is the duration of synching more frequent and makes sure there is no slip?
  • Ted  VE3TRQTed VE3TRQ Member ✭✭
    edited March 2019
    Meinberg talks to NTP (Network Time Protocol) servers on the Internet. The daemon (background process) nudges the internal clock sufficiently to keep it accurate - and those "nudges are minuscule once the clock has been brought "close enough". You will never see large clock time changes. Also, the algorithms are designed to look after network delays and latencies to the NTP servers. Meinberg is a Windows NTP client implementation - all Unix systems have an NTP client built in.

    If you want independence on a Windows machine, buy NMEATime (or install one of the free alternatives) and hook up a GPS receiver to your PC.
  • Neal Pollack, N6YFMNeal Pollack, N6YFM Member ✭✭
    edited March 2019
    Hi Craig:

    Just be aware, that Meinberg NTP for Windows 10 occasionally has problems.
    While NTP is an amazing time protocol, the implementation on windows seems to
    have more problems that what we use on Linux in the I.T. industry.   Several times
    a month when I boot up windows 10 to run FT8, I notice no decodes.  If I start the meinberg NTP status windows (Which is just "ntpq --peers" for you linux users),
    I can see bizarre delay and offset numbers.   If I manually restart Meinberg NTP, then it comes back into time sync and FT8 works.

    So if you choose Meinberg NTP, I suggest placing the icon on your desktop for RESTART.

    Cheers,

    Neal
  • Neal Pollack, N6YFMNeal Pollack, N6YFM Member ✭✭
    edited March 2019
    The only problem with ToyNTP, is that it has not been updated since Windows 7 time frame.  So it has no idea how to turn OFF the Windows 10 time service, and both will fight each other.  Since windows time service does not update Windows 10 very often, it may appear to be working just fine anyway.   But the newer programs automatically turn off the windows 10 time service processes, so that they can control the clock without fighting the operating system.

    Neal
  • Dwayne_AB6ADwayne_AB6A Member ✭✭
    edited March 2019
    I did update Windows NTP refresh timer and that worked ok for me... Given all the feedback, I made the jump to Dimension 4... It shuts down the Windows NTP task and is prepopulated with all the best time sources. I cut the list down to my favorite local sources.
  • Arvind MallyaArvind Mallya Member ✭✭
    edited March 2019
    Thanks, I downloaded the Meinberg software but it hung halfway through. I'll have to do it again not sure why it did not complete the installation. I also found reloading DAX seems to fix the problem. If I start the SDR program and it loads automatically loads CAT and DAX, but sometimes there are no decodes. When I reload DAX it seems to start a whole lot of activity.
  • Neil D Friedman N3DFNeil D Friedman N3DF Member ✭✭
    edited March 2019
    Interesting.  In my experience (using Meinberg), being two seconds or more off from another station is rare -- perhaps one half of one percent.  I don't recall ever losing a "rare one" to a time difference. 
  • John - K3MAJohn - K3MA Member ✭✭
    edited March 2019
    I am glad your satisfied and it meets your needs.  All I can say is you can't know what you have missed when your not decoding it.  This is also the case when you compare FT8 decoding in WSJT-X with other programs.  I recently did a comparison running WSJT-X alongside another decode program using the same feed from DAX.  I decoded and worked 5X2S using the other program.  There was no decode in WSJT-X to even let me know he was there.  The other friends with similar stations were on the band at the same time and claimed I worked a false decode.  Nope, the next day the contact appeared in the 5X2S clublog.

  • John - K3MAJohn - K3MA Member ✭✭
    edited March 2019
    @Arvind - DAX taking a fit and not decoding has been a problem for a long time.  I and several other suffer from the same issue.  It is annoying when you move to work a spot you saw using one of the digital modes and QSY and load up the software only to find DAX is not working correctly.  Then you have to waste time and shut down and restart programs.  I have missed a couple DX contacts as a result of these DAX failures.  However, there is a work around if you use Windows that I posted a long time ago and you can search to find it.  You can write a short batch program to automatically shutdown DAX and restart it.  I have found doing that a couple times a day seem to keep it working when I need it.

  • KevinKevin Member
    edited March 2019
    Never had a problem with Meinberg in the years I've used it. Follow the install instructions and disable Windows time updates. That may be what's giving you glitches.

    Kev


  • KevinKevin Member
    edited March 2019
    Time Fudge!!! So cool. I always thought there should be something out there to nudge the clock. It's almost like a community time source. 

    I use Meinberg. Most of the DT readings I see are +0.2 to +0.4. Not a big deal but I'm a bit odd about zeroing things out. I upset people adjusting SWR manually.

    With Time Fudge, i've got most everyone zeroed, a few +/- 0.2 and one outlier at 1.2.

    Cool! Another thing to tweak.

    73,
    K4VD Kev
  • Neil D Friedman N3DFNeil D Friedman N3DF Member ✭✭
    edited March 2019
    I guess I don't understand.  If I show within, say, 0.4 seconds of the 15 or so stations appearing on my screen, how would I even know that there is another station 3.0 seconds off that I can't see and that I have to "nudge" my time in order to work?
  • Stu      2E0XXOStu 2E0XXO Member
    edited June 6
    I have been using Dimension 4 since i started with jt9+jt65.
    it still works great, you just pick a local sntp server near you and set the update interval and leave it alone to get on with the job.

    https://download.cnet.com/Dimension-4/3000-2094_4-10039998.html

    stu

    p.s. but as mentioned by Bill its not totally reliable ! but it is free !!
  • Bill EnglishBill English Member
    edited March 2019
    I was using Dimension 4 for a time, and I noticed occasionally the server would be down and I would get no alert. I just had to check on it from time to time and change the server as needed. I felt that was more trouble than it was worth and purchased a GPS unit that I use for an external 10Mhz source for my radio and the serial connection running NMEAT2 to my PC. Well worth the small investment. 

    When I complained about my 1st PC not keeping time correctly, my IT mentor told me, you bought a computer, not a watch. 
  • Neal Pollack, N6YFMNeal Pollack, N6YFM Member ✭✭
    edited March 2019
    Hey John K3MA:

    Help me understand;  It appears as though you are claiming that one or another time sync programs might not let you decode FT-8 as well as another?  I might have read your reply wrong?    But, regardless of the choice of program for time sync, both WSJT-X and JTDX have a column in the decode window called DT (Delta Time).
    You can rapidly judge if ANY time sync program is working or not, by looking for
    the majority of the other stations in your decode window to have a DT value of .1 to .4
    or so.  Of course, there are always a few other people with clocks that are way off, so you will also see a few that have DT of .9, 1.3, or even 2.4 seconds.

    {For what it is worth, the few times that I have had Meinberg NTP fail to start properly,
    was noticed by seeing few decodes and seeing that the ones that did decode all had high DT numbers in the DT column in WSJT-X decode window.  Simply restarting Meinberg NTP made it randomly choose different time servers from the pool, and then it worked fine after that.}

    So if I understand correctly, if your DT values are low (under half a second) you ARE going to decode that station as long as they have enough signal strength [NOT -39dB :-) ]    So if your time is close enough in sync, less than a half second, decoding a weak one near -20 would be up to the difference in the decode and FFT math used between WSJT-X or the JTDX software applications (as well as your audio input level
    being properly adjusted for the WSJT-X or JTDX application).

    Do I have that right?

    Neal
  • KevinKevin Member
    edited March 2019
    I've been experimenting. I'm able to get the average (median?) DT down to 0 for most of the CQ calls I see. I'm actually set to -0.6 (I guess delaying my clock by 600 ms). So, if I wanted to see if there was anyone of interest +/- 2 seconds I might nudge up and down and see who's there. 

    I just set it to -2 seconds. I see IZ1MLQ at 0.8, M0JBF at 0.4, n2ujz at -0.2.

    Set to 2 seconds I see nobody within 2 seconds.

    To make this work, I had to turn off Meinberg as it kept adjusting the clock. With Meinberg running, Time.is reports exact and I see an average of 0.5 for DT. When I shut off Meinberg and nudge to -0.6 then most DT falls right around 0 but time.is reports 400 ms off (not 600 as I'd expect). 

    It seems to me, and just guessing here, ignoring ntp sync'd time and going by FT8 community time (made that up), I can fall right into a good average of zero offset.

    Now I'm wondering... if, for instance, I see DT=0 for a call, will he see DT=0 for me? Now I think I'm overthinking it.

    73,
    Kev K4VD

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