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

David davidwhess at gmail.com
Thu Aug 4 14:47:18 EDT 2016

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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