[bars] WSJT-X tip

Wed Aug 9 10:23:23 EDT 2023

Your phone has GPS in it.  Any app on the phone can access this information. No need for an internet time server or even actual cell service.  Actually the NTP server is the least accurate method.

GPS modules are cheap.  The time from them can be captured in a serial interface of a laptop, RPI or Arduino.  GPS time is locally accurate, based on an atomic clock in the bird,  even corrected to Nano Seconds for relativistic effects by the GPS software.  It comes from a LEO (50 miles) satellite has far less propagation delay than anything over the internet.  That propagation delay is corrected in the GPS module based on multiple satellites which transmit their individual ephemerides. For some digital modes, this is a real advantage but also works anywhere that RF can be sent or received (unlike a cell phone connection)

The relativistic effect correction is even based on tables, stored on the bird, of inconsistent gravity effects.   Other than a private atomic clock (which tends to be less portable) this is the most accurate time reference available, including over the internet.   By the way, distributed databases that use time variant locking use GPS and not NTP.

If there is a cell tower, the time on the phone comes from the towers GPS antenna.  If you think about it, the entire function of a cell phone is a digital mode that depends on exacting time agreement and uses that for ECCs.

Geoff W1GCF

From: bars <bars-bounces at w1hh.org> On Behalf Of Juan Jiménez
Sent: Wednesday, August 9, 2023 8:59 AM
To: Jonathan Lyna <jonlyna at yahoo.com>
Cc: w1hh <bars at w1hh.org>
Subject: Re: [bars] WSJT-X tip

Most everywhere you don't have wired internet you usually have cellphone coverage. I use the hotspot on my phone to connect to my computer, and it then picks up the time as usual from the NTP server. Since i don't have to pay for the hotspot, I allow others around me to do the same if i am in a group. A GPS puck will do the job, I suppose, but sometimes you are inside and it can be a problem seeing the available GPS satellites in the constellation.

Also, most computer hardware clocks these days are VERY accurate. If you sync before you leave home there is little chance the clock will drift any significant value.

73,

K1CPR

Juan

On Wed, Aug 9, 2023 at 6:06 AM Jonathan Lyna <jonlyna at yahoo.com <mailto:jonlyna at yahoo.com> > wrote:

What about the people that want an external hardware device to sync their clock to something like a GPS satellite (an atomic clock in the sky, instead of an atomic clock at the end of a wire)?   A method that uses this would be portable, wouldn't it?   Of course you could sync the clock before you head out manually, or have it always "good to go"  automatically,  but what if you want to synchronize using radio waves, before you FT8 over radio waves?  A fully "wireless" solution.

Could you make a GPS dongle work in these cases?

Jon 

On Saturday, August 5, 2023 at 08:20:09 PM EDT, Juan Jiménez <k1cpr at bd5.com <mailto:k1cpr at bd5.com> > wrote: 

Considering that most of our members are older, I think the "set it and forget it" method is much more reasonable than having to remember to sync. It will also help with any other app that requires an accurate clock.

73,

K1CPR

Juan

On Sat, Aug 5, 2023 at 8:09 PM Christopher Wood <christopher.wood at firelinkllc.com <mailto:christopher.wood at firelinkllc.com> > wrote:

Yes, this method works. However, if you're just an occasional FT-8 (JS8Call, etc.) user (like me), you can skip the regedit method and just sync when necessary through the following:

1.	Right-click on the clock
2.	Left-click "Adjust date/time" (usually near the top)
3.	On the Date & time screen (you may have to scroll down a bit) and left-click on the "Sync now" button

Your clock only needs to be with about 500 msec of UTC.

This site www.time.gov <http://www.time.gov>  will give you a good estimate of the difference between your clock and UTC (the system corrects for network delays).

Good luck,

Christopher KC1GHR

  _____  

From: bars <bars-bounces at w1hh.org <mailto:bars-bounces at w1hh.org> > on behalf of Juan Jiménez <k1cpr at bd5.com <mailto:k1cpr at bd5.com> >
Sent: Saturday, August 5, 2023 6:41 PM
To: w1hh <bars at w1hh.org <mailto:bars at w1hh.org> >
Subject: [bars] WSJT-X tip 

One thing FT-8 is sensitive to is your computer's clock, which has to be accurately sync'd with a time server. If you are running on Windows, the default is to update your clock once a week using the NTP protocol and a Microsoft time server. WSJT-X recommends installing software to update more often, but that's not necessary. It's easier to use Regedit. The key to change the auto time sync time interval settings is located at: 

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient

The key name is SpecialPollInterval and the type is DWORD. The default value is 604800 (decimal) or 0x00093a80 (hexadecimal). That number is the seconds between update. Change the value to 86400 to auto time sync every day. Don't make it much shorter than that or you risk getting blocked for swamping the server with requests. This works on all versions of Windows back to XP.

Windows uses NTP, not SNTP, and you can also change the NTP server it uses here:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\Parameters

...in the NTPServer key.

73, 

K1CPR

Juan

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