[SMCARA] [Non-DoD Source] JT65

[Dave Q]

Tom, here is a blurb from nw7us.us that talks about using a GPS for time
sync.....

*YOU MUST SET YOUR PC CLOCK TO THE EXACT TIME*

Regarding the requirement to keep your PC clock synchronized: If your
station is at home, and you have internet access, then you should use a
time sync client such as Dimension4 or Symmtime. Both are free and readily
available online. The reason you want this is that *the built-in time-sync
feature in Windows XP/Vista/7 is not accurate enough to allow proper JT65A
operation*; you should disable it and *use a dedicated sync client*.

THIS CANNOT BE STRESSED ENOUGH

Your PC clock MUST be set very accurately--and the built in PC
synchronization is NOT accurate enough--in order for JT65A to correctly
sync with other stations!

If you don't have internet access at home, or are working rover/portable,
then you might consider using a GPS dongle together with a software package
that locks the PC's clock with the time signals received via GPS. (Many GPS
vendors provide a small software utility with the GPS which will do just
that, but I've also used the UIView32 APRS software package which can link
up with many GPS dongles and adjust your PC's clock.) If you're in a pinch,
on a tight budget, and still want to work JT65A, you can try syncing to the
WWV tones from NIST in Boulder, CO or other shortwave sources. F6CTE's
MultiPSK package comes with a WWV clock receiver application (clock.exe),
but bear in mind that PC clocks tend to drift a lot even during a short
period of time, so you'll have to tune back to WWV and readjust your clock
about every 30 minutes. For best performance you'll want a GPS dongle;
these can be purchased online for about US$30.

73... Dave - W3DLQ



On Wed, Jan 6, 2016 at 3:54 PM, Clarke, Tom AIR4.0P NATOPS <
frederic.clarke at navy.mil> wrote:

> Interesting.  The same issue exists in running WSPR.  I have been using
> Dimension4 (on an XP and Win7 machine) at home with good luck.  I was
> running a 17 m WSPR beacon at K3NAL on base and received a couple of emails
> indicating that my timing was grossly off.  Since there is no internet
> available at the station, I had to "hack" the time with WWV or Dominion
> Observatory Canada, but it soon drifts off.
>
> Tom, DL2WB, who reported my problem initially, described his system of
> syncing the time using a GPS receiver.  I now have a $16 GPS kit in work on
> my bench and hope to have it going soon!  Another possibility is the
> Rubidium time standard ( so-called atomic clock) in the next room!   50
> feet of RG-59 to bring the 1 PPS time code to the rig might solve all my
> problems.
>
> 73 Tom/W4OKW
>
> -----Original Message-----
> From: SMCARA [mailto:smcara-bounces at mailman.qth.net] On Behalf Of Dave Q
> Sent: Wednesday, January 06, 2016 3:19 PM
> To: smcara at mailman.qth.net
> Subject: [Non-DoD Source] [SMCARA] JT65
>
> I've been reading about JT65 and each article states that computer time
> has to be set accurately.  They all say Windoze time sync is not accurate
> enough.  I have used Dimension 4 in the past to set computer time.
>
> So... what are you using for time sync?
>
> Any suggestions on JT65 software would be appreciated especially any that
> can be used with HRD.
>
> 73... Dave - W3DLQ
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