JT65 on 40M Newby Help

David Ahrendts

Need a quick Elmer for JT65.
I have the fabulous  and remarkableFlex 6500 operating just wonderfully on 20M with WSJT-X and JTAlertX (it talks!). So in our current propagation cycle, like everyone, I switch to 40M after 20M dies and I see a ton of really strong signals North (that is, higher) of 7.076 MHz, and like a good SSB operator I set the mode to DIGL. Decodes nothing. Switched tonight to DIGU on 40M and OMG, the heavens open to a ton of strong signals and it starts talking away! YAY!
So, I have learned it is custom to use use DIGU mode on the 40M band that we would regard as LSB, Lower Sideband for phone -- am I correct. And where does one use DIGL?

George KF2T

You are correct. USB 
DIGL is not used too often (I hear some FreeDV guys use it 40 and below). RTTY is in LSB, but has its own Flex mode.

Welcome & enjoy! Hope to work you soon.

David

Digital is mostly usb on any band. FreeDV follows voice mode practice even though it is digital.

Bill Turner

I never use DIGIL for anything. All digital modes are DIGIU and of course, RTTY has its own mode.

73, Bill W6WRT

Ria

Use DIGU as that turns off all speech processing. WIth DAX the signals are "perfect." 

YV5WZ

DIGU  is  .....enjoy it

dan flynn

So get ready to loose  sleep.  Now you'll be tracking the grey line on 40 meters till dawn and then back to 20... Enjoy.. hope to work you..

Al K0VM

In the voice sub bands, it is common practise to follow the voice convention and use DIGL for things like SSTV, EasyPAL & FDV on 40,80& 160.  Outside the voice sub bands, digital modes are  generally all DIGU. Except RTTY which now has is own mode in FLex. 

But there maybe exceptions.

AL, K0VM

Keith Flint

Your clock may be a bit out of sync with WWV UNIVERSAL TIME. Download and install network time. Or others.

Ria

I did not know that about SSTV. Thanks. 

Ria

You need very accurate clock sync for WSJT modes, so yes that is correct.

Most people use dimension 4 or Meinberg NTP to sync their computer clocks. The built in time sync facility in Windows is not sufficient. 

Meinberg: https://www.meinbergglobal.com/english/sw/ntp.htm#ntp_stable
Dimension 4: http://www.thinkman.com/dimension4/

len

For JT65 use DIGU as others have indicated. I have been playing with WSPR using a Raspberry Pi transmitter with the TAPR board.  You can see the reports on http://dev.wsprnet.org/drupal/wsprnet/map
The TAPR board is http://tapr.org/kits_20M-wspr-pi.html
For 20mW of power, I can do quite well!
WF2V

David

I have good success with WSJT-X using the standard Windows 10 Internet Time settings to synchronize with an internet time server. I have changed it to use time.nist.gov.

The key issue he is having is the use of upper for digital modes with the few exceptions as noted.

Al K0VM

Wether or not the windows time setting are sufficient is determined by the stability of the PC clock. Many ( most??) PC clocks are not sufficently stable.
.
AL, K0VM

Ria

Built in time sync may or may not work. Joe K1JT recommends using a better program than the built in time sync feature.

The main reason is that Windows time sync doesn't sync as frequently, or it didn't do so in the past. Dimension 4 syncs much more frequently and Meinberg continuously keeps track of clock skew and syncs (as does the unix NTP daemon in general). 

David

Correct Windows client polls weekly by default. That can be adjusted with a regedit. Just don't make it too frequent to avoid becoming abusive to the NTP servers. Here are some links to better understand Microsoft time service and NTP.

HKEY_LOCAL_MACHINESYSTEMControlSet001 servicesW32TimeTimeProvidersNtpClient SpecialPollInterval 

http://www.windows10update.com/2015/08/windows-10-tutorials-155-change-the-time-synchronization-inte...

https://technet.microsoft.com/en-us/windows-server-docs/identity/ad-ds/get-started/windows-time-serv...

http://www.ntp.org/ntpfaq/NTP-s-algo.htm

Ria

Windows is more like SNTP, as is D4. SNTP does what you describe - it looks at the time returned from the server and makes a massive update at fixed, specific intervals.

Meinberg and other NTP daemons on the other hand, look at the stability of the clock and the NTP sources it is connected to and make corrections on an as-needed basis. This is much better than polling at fixed intervals since corrections are applied gradually and on an as-needed basis. Not all NTP sources are equal, and most of us should be using the NTP pool anyway to spread the load. My eventual goal is to have a stratum-1 on our local LAN using GPS or maybe a WWVB receiver.

wb7ond

I like to use NMEATime, when at home in the shack I set it to network, in the park, I set it to use my Holux Bluetooth GPS receiver set out in the bushes.  Only downfall is I have to put a string on the GPS receiver so I don't leave it behind.  It updates the computer and provides it own clock face, has free and paid version.