WSJTX-FT-8 Clock Synchronization

Arvind Mallya

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.

Mark NS9N

Go to the FT8 web site and there is a link to synchronize your clock. Click on it and all should be good.

Dwayne_AB6A

Tom Worthington

Sterling, AK1K

Craig_KØCF

Justin W4JTD

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

N8AUM

Craig_KØCF

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 - AF3K

Neil D Friedman N3DF

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 AB6BT

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 VE3TRQ

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_AB6A

Here's a little project for everyone... http://www.dxatlas.com/ToyNtp/ The Garmin 18x which has time sync capabilities is $85.

Arvind Mallya

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 VE3TRQ

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.

John - K3MA

Neal Pollack, N6YFM

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, N6YFM

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_AB6A

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 Mallya

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 N3DF

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 - K3MA

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 - K3MA

@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.

Kevin

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

Kevin

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 N3DF

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 2E0XXO

Bill English

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, N6YFM

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

Kevin

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