GA 2.4.0. DT margin smaller now? #FT8 #Timesync


Chris, HB9DFG
 
Edited

Dear Group

I succsessfully installed new WSJT-X 2.4.0 beside the old version 2.3.1 and saw a local station
on 2m with a clean FT8 signal on v.2.4.0 I could not decode while I could decode this same station
on another computer and tranceiver with v 2.3.1 clearly readable.

Then I remarked his DT value (on v2.3.1) which was -1.1 compared to other stations I received on
both time synchronized computers which always have +/- 0.0 to 0.2 on DT.

Now can someone please check or confirm that the newest v 2.4.0 has a smaller margin of "DT"
than all the versions before? Has this been decreased for a special reason and how much are the
limits now? Seems at DT 0.5 FT8 is still decoding - have to wait for stations with bader timings
again :-)

Edit:

While observing the HF bands I saw decodes with a DT from -2.4 to +2.5 decoded fine with GA 2.4.0,
so nothing special so far. But wonder why this strong local -1.1 DT signal did not appear on 2m.
Will try to save a wave file next time this appears again.

Regards, Chris, HB9DFG


Jim Brown
 

On 5/26/2021 7:49 AM, Chris, HB9DFG wrote:
Now can someone please check or confirm that the newest v 2.4.0 has a smaller margin of "DT"
than all the versions before?
No, it does not. Using it yesterday during a massive 6M opening, I was decoding signals with DT as high as 2.5 sec

73, Jim K9YC


Chris, HB9DFG
 

Hi Jim

Thanks for your info, and as you perhaps saw, I also added an edit of my mail a little
later on.
After my observation with this undecodable -1.1 DT signal I listened around the activ
HF-bands. I quite quickly saw a few stations with DTs of +1.1, +2.0, +2.2, +2.4 and
also +2.5, but for those with big "minus" values I had to wait much longer ;-)

It needed some time until I got the first -0.5 and half an hour later I saw someone
with -1.6 until I finally got also a -2.4 DT so it seems the DT margin is around +/- 2.5.

Maybe it's good to know, cause I did not found an info yet in the manual about the
maximal possible/allowed DT value (+ or -).

Regards de Chris, HB9DFG


William Smith
 

I run a Python program to get a histogram of dt from ALL.TXT and I’ve never seen anything outside +/- 2.5 seconds. 

If you are out by 1/2 second or more as determined by https://time.is/ then you probably aren’t keeping very good time and will eventually drift out of decodable dt from the rest of the universe. 

There are others but I’ve found
To be pretty easy to install and forget for Windows machines. 

73, Willie N1JBJ


On May 27, 2021, at 10:06 AM, Chris, HB9DFG <hb9dfg@...> wrote:

Hi Jim

Thanks for your info, and as you perhaps saw, I also added an edit of my mail a little
later on.
After my observation with this undecodable -1.1 DT signal I listened around the activ
HF-bands. I quite quickly saw a few stations with DTs of +1.1, +2.0, +2.2, +2.4 and
also +2.5, but for those with big "minus" values I had to wait much longer ;-)

It needed some time until I got the first -0.5 and half an hour later I saw someone
with -1.6 until I finally got also a -2.4 DT so it seems the DT margin is around +/- 2.5.

Maybe it's good to know, cause I did not found an info yet in the manual about the
maximal possible/allowed DT value (+ or -).

Regards de Chris, HB9DFG



Chris, HB9DFG
 

Hello Willie

Yes, I am personally quite in time of course with this one here:
bkttimesync 
It's from an italian HAM (IZ2BKT) and works for me very well on WIN7 and 10.
But "BKTTimeSync" seems not be very known like "meinberg" for USA-HAMs so
I think it is worth to mention it once here, too :-)

Chris, HB9DFG


Gary - AG0N
 



On May 27, 2021, at 9:57 AM, Chris, HB9DFG <hb9dfg@...> wrote:

But "BKTTimeSync" seems not be very known like "meinberg" for USA-HAMs so
I think it is worth to mention it once here, too :-)

I’ve been using it a few years now and really like it.  I had trouble with Meinberg a few years ago and found BKT at that time.  Set it and forget it.  Meinberg would occasionally have trouble with the server connections.

Gary - AG0N


Jim Brown
 

On 5/27/2021 11:01 AM, Gary - AG0N wrote:
I’ve been using it a few years now and really like it.  I had trouble with Meinberg a few years ago and found BKT at that time.
We've used it when roving and on FD with no access to internet and using GPS for sync. It works OK for that, but with an internet connection, http://www.timesynctool.com/ is FAR better and also free. I've been using it for about 10 years, since first starting with JT65.

73, Jim K9YC