[time-nuts] Using the HP 58503a to correct your PC clock

Ron Ott ronott at sbcglobal.net
Thu Aug 4 15:05:13 EDT 2016

My granddaughter would love to know I have a Tardis program. (-;>  Lots of things to try here, just to get a more accurate clock. No wonder there's a time-nutz group!

      From: David <davidwhess at gmail.com>
 To: Discussion of precise time and frequency measurement <time-nuts at febo.com> 
 Sent: Thursday, August 4, 2016 11:47 AM
 Subject: Re: [time-nuts] Using the HP 58503a to correct your PC clock
The old Tardis program for Windows (Tardis2000 now) handles it
correctly by altering the rate and only jamming the time if it is
outside of a specified window but I do not think its GPS mode supports
the 1 PPS signal.

I am not sure if Tardis works with Windows 7 and above though; I
forget to test it on my Windows 7 test system when I had it.  It is a
pretty old (but free) program.

On Tue, 2 Aug 2016 23:28:06 -0700, you wrote:

>The WRONG way to adjust a PC clock is to set the TIME periodically from
>some standard.  When you do this then the time on the PC is not running at
>a constant rate.  The correct way to do this is to adjust the PC's clocks
>RATE.  You make it runs slightly faster if you notice it is getting behind
>and slightly slower if it is running fast.
>Think about what you would do to a real physical clock.  You would not set
>it every few minutes, you'd adjust the rate and wait a little while to see
>if the adjustment needs refinement or not.
>Most operating systems in use today run NTP to keep their clocks in order.
>Well most OSes except for Windows.  Microsoft uses a vey much simplified
>version of this that does the wrong thing and periodically sets the PC's
>clock.  You could enable this and likely, maybe reach your +/- 100ms goal.
>  Not the "real" NTP is a free program and not hard to set up so you can
>have 1ms level accuracy without much effort and better with some work.
>On Tue, Aug 2, 2016 at 8:13 PM, Ron Ott <ronott at sbcglobal.net> wrote:
>> This has probably been covered in the past, but is there a way correct or
>> control a PC (Windows 7) clock with the HP 58503A GPS receiver? I just
>> bought one (on the way now) and have a copy of satstats50 on hand. I've
>> been using Dimension 4 and I'm surprised at the size of correction every
>> couple minutes to my PC clock.  I'd be happy if my PC clock were accurate
>> to plus/minus 100ms.
>> Ron
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