On Mar 23, 8:29�pm, Phil Kane wrote:
On Sun, 23 Mar 2008 22:53:54 EDT, Klystron wrote:
� Wouldn't it make more sense to include WWV and WWVH along with
WWVB?
Are you familiar with the Internet-based ntp system? Then, there is the
matter of GPS, which has a time capability that is incidental to its
navigation function.

Want some fun? �Compare the time ticks received from �WWVB
, WWV,
NIST-on-line, and GPS. �What, they are not all simultaneous? ï
¿½Welcome
to the real world. �GPS time does not correlate with UTC by any me
ans
(several seconds difference).

In one of the first digital military command and control system that I
was involved in during the early 1960s, we used rubidium standards at
our switching centers to get accurate time synchronization, and even
then it was rather crude because the line delays varied so much. �
HF
propagation (WWV/WWVH) is even worse in that regard.

I've compared each of our three radio-set clocks at this residence (in
Los Angeles) and find excellent correlation between their one-second
changes and both WWV and WWVH. Don't have any GPS receiver
to try the same.

In 1960, while working in the Standards Lab of Ramo-Wooldridge Corp.
in Canoga Park, CA, I got to pull some OT on Saturdays to measure
the difference between east coast transmissions of WWV and the
local General Radio frequency standard. Just a plain old quartz
crystal standard oscillator driving divider chains to the built-in
clock.
I would record the microseconds of difference between local clock
ticks and WWV ticks from the east coast. Not much variation in a
week's time, don't remember just how much (it was 48 years ago).

Yes, propagation on HF does vary but it is sometimes exaggerated.
Before R-W went into a business tailspin, the Standards Lab was
ready to get a low-frequency HP receiver for 20 KHz to improve on
establishing a local, secondary frequency standard. No joy on that
corporation which was eventually sold off. All I ever got to see was
the 'diurnal shift' of 20 KHz phase recordings at sunrise and sunset.
:-)

73, Len AF6AY