[DSP-10] A Clock Question

[Bob Larkin]

Hi Dave,

And thanks to all that have commented so far.  Keep the UTC feedback coming.

The mods for UHFA that I have now will handle UT+ binary format and also 
NMEA 0183 sentences. This is all done. The catch is that to get accurate 
timing with NMEA, you still need a 1PPS input, that can come in on the 
9-pin serial plug.  Some such as the Sandpiper GPS provide the 1PPS. More 
later when this all gets a little farther along.

Others NMEA input time setters are also available as stand alone programs. 
Someone may want to comment.

73
Bob

At 03:11 PM 3/12/2006, you wrote:
>answer: no problems
>
>all my radio computers run in utc for some of the reasons you mention
>
>what i need is a DOS program to automatically set the clock from an nme
>gps stream...like nmeatime does in windows. Havent found one yet
>
>dave
>
>ww2r
>
> > Hello All,
> >
> > I am in the process of "unifying" the clocks used inside the DSP-10
> > program
> > UHFA.  This is spurred on by wanting to have automatic, precision setting
> > of the clock from a GPS.  I have that part more-or-less under control, but
> > I am seeing complications in the handling of time zones, and particularly
> > daylight time.
> >
> > First a couple of comments. DOS allows for time zones through the
> > environmental variable TZ, which can be read and applied.  The C routines
> > use this to automatically change the offset for daylight time, if this is
> > specified, i.e., "SET TZ=PST8PDT"
> >
> > DOS does NOT change the computer time in April and October, it only
> > automatically adjusts for it when computing GMT from local time. If you do
> > not use the DOS command TIME it will be wrong.  Windows (I don't know
> > which
> > versions) allows for automatic time change, if Windows is run.
> >
> > All of this becomes very simple if the TIME command is set to GMT and the
> > environment is "SET TZ=GMT0"
> > With this, the program never checks for daylight time, and, it turns out,
> > all the clock operations can run from a single software time source (the
> > source that has the daylight info does not have fractional seconds, and
> > visa versa).
> >
> > Tell me what kind of problems running everything in GMT would create for
> > people?  I have always done this, but I know others have used local time
> > in
> > some way.
> >
> > Many thanks,
> > Bob Larkin  W7PUA
> >