WSJT-X -- A Tip and a Question

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  • Updated 5 months ago
As some of you may recall I am a relatively new Flex 6400M owner, having more fun than a human being should be allowed to have.  My main mode lately has been FT8 on WSJT-X software.  Learned something very interesting today about WSJT-X/FT8, which is that you really really really do have to have your computer clock synched with GMT.  I'd seen that when Reading TFM, but didn't really pay much attention.  Well, today I was calling CQ on FT8/20M and although the waterfall indicated guys were coming back, I didn't synch with them into a QSO (perhaps bad terminology there).  Finally someone "texted" me (question about that below) and told me that my clock was way off.  By then I had figured out that there was some problem in that regards.  Ultimately I adjusted my Windows clock to NIST time, called CQ, someone came back and immediately synched; problem solved.
My sincere apologies to the many people who tried calling me this morning and could not connect.  My noob bad.
You can tell if your clock is off, apparently, by looking at the "DT" (delay time) column in WSJT-X.  It should be something like .3, .4 or somesuch.  For me before I re-synched the clock it was more like 3.0 and so forth.  Obviously I had no clue what this column even meant, but that apparently is an easy way to tell if you are relatively synched.
So the obvious (now) lesson is, check your computer clock regularly to ensure that it is synched to NIST/GMT time.
Now, here is a question from a noob -- how the heck did that guy "text" me?  I'll have to RTFM again in WSJT to see if it has that capability -- how does that work?
.... the Flex adventure continues ... 
de Roger W6VZV
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Roger J. Buffington

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Posted 5 months ago

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Ken - NM9P, Elmer

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If you also have JTAlert running, there is a messaging module included. It makes it handy to coordinate beam headings, Transmit times, etc.

I have used it a lot to ask stations to listen for me in another band, etc.

Ken - NM9P
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Bill -VA3WTB

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Wow, that's cool. never knew that.
you know what I think would be neat? If we could text other Flex users on air from SSDR and have it pop up on their screen at the other end.
(Edited)
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David Decoons wo2x, Elmer

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In JTAlert click View and then Text
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Clay N9IO

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Thanks for the tip Ken, still learning here.
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Ken - NM9P, Elmer

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If JTAlert has focus, hit F5 will also bring it up. But the windo times out quickly after it pops up. It also grabs your text entry focus when someone texts you...caused a lot of. Messed up log entry or text entries. But overal a handy tool.
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David Ahrendts

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FT-8 is pretty cool. I actually setup a second screen to display just FT-8 and JTAlert while keeping my primary display for the Flex 6500. There is a nifty precision time sync program called Dimension 4 that keeps you precise:  http://www.thinkman.com/dimension4/   Runs totally in the background.

David A., KK6DA, Los Angeles
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Tim - W4TME, Customer Experience Manager

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D4 is an SNTP client.  SNTP makes large corrections in time rather than smaller corrections over time which is what NTP does.  Meinberg (https://www.meinbergglobal.com/english/sw/ntp.htm#ntp_stable) is an NTP client.

While a full-featured NTP server or -client reaches a very high level of accuracy and avoids abrupt timesteps as much as possible by using different mathematical and statistical methods and smooth clock speed adjustments, SNTP can only be recommended for simple applications, where the requirements for accuracy and reliability are not too demanding.

By disregarding drift values and using simplified ways of system clock adjustment methods (often simple time stepping), SNTP archives only a low-quality time synchronization when compared with a full NTP implementation.

SNTP version 4 is defined in RFC2030, where it reads: [quote] "It is strongly recommended that SNTP be used only at the extremities of the synchronization subnet. SNTP clients should operate only at the leaves (highest stratum) of the subnet and in configurations where no NTP or SNTP client is dependent on another SNTP client for synchronization. SNTP servers should operate only at the root (stratum 1) of the subnet and then only in configurations where no other source of synchronization other than a reliable radio or modem time service is available. The full degree of reliability ordinarily expected of primary servers is possible only using the redundant sources, diverse subnet paths and crafted algorithms of a full NTP implementation." [unquote]

Therefore the term "NTP time server" or "NTP compatible client" can - by definition - describe a system with a fully implemented NTP as well as any other product which uses and understands the NTP protocol but achieves far worse levels of reliability, accuracy and security.
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Ken - NM9P, Elmer

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I also use Meinberg, and it keeps my clock dead on.
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Roger J. Buffington

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Got it.  Installed.  Thanks everyone.
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Roger J. Buffington

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I am trying to get my shack set up to accommodate a second screen as you are doing. Like to have a dedicated screen for WSJT-X and JT Alert.
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Bill -VA3WTB

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Roger it is fun to watch what your doing, ever since you got your Flex you are doing more things with it over the last month then I did over 10 years.

I remember things your asked before your radio,,like, how hard is it to do digital?
Now look at you go!!!
(Edited)
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Craig - KØCF

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Roger,
Also follow Tim's advice and get Meinberg. It's free and works beautifully. Also see the website https://time.is/  to verify your clock. With Meinberg, mine is always precise. In fact, right now I show only 3 milliseconds off exact time.

73,
Craig, KØCF
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Roger J. Buffington

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Will get Meinberg as soon as I get home from work.  This community forum is so great!  Learn things here every day.
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Clay N9IO

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Don't feel bad Roger I too figured it out the hard way after the fact of course. Missed a few contacts the same way. Felt like a lid but eh stuff happens.
Have fun with that new rig.
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Roger J. Buffington

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Oh, screwing up is half of the fun, but I try to minimize it.  :-)
I did RTFM but guess my eyes just kind of glided over the part about synching the clock, and to be honest it worked fine until today; apparently windows screwed up the clock.  Glad to have figured this out.  But yes, apparently I missed many contacts this morning.  Life will go on, LOL.
de Roger W6VZV