[Milsurplus] Re: Loran C

[J. Forster]

There is a difference between time (time of day) and time interval.

WWVB's TOD is not very good
LORAN-C does not transfer TOD AFAIK
GPS can be a pain because of satellites appearing and leaving. More receiver smarts
helps there.

All in all, I prefer LORAN. I'm in ground wave of a transmitter, BTW.

It can be interesting to watch the 60 KHz WWVB phase shift wrt my local crystal or Rb
source as a function of atmospheric conditions and TOD.

-John

Brooke Clarke wrote:

> Hi John:
>
> The radio time transfer systems, in chronological & quality order are:
> WWV - H.F. radio, suffers from large path length changes
> WWVB - 60 kHz - much better than WWV, but still has a dinural change
> LORAN-C - 100 kHz pulse system , much more stable than WWVB
> GEOS Satellite - has variable path length that needs corrections, still
> in service
> GPS - by knowing the receiver position, the time can be very accurate.
> All the prior systems required user input to determine the propagation
> delay, but with GPS  you get an absolute time referenced signal (need to
> correct for antenna to receiver time delay).  Less than 30 ns from the
> UTC edge.
>
> Have Fun,
>
> Brooke Clarke, N6GCE