[time-nuts] Time syncing WiFi routers using FM radio

Richard (Rick) Karlquist richard at karlquist.com
Thu Nov 12 09:23:00 EST 2015

On 11/12/2015 12:04 AM, Hal Murray wrote:
> I think it was HP that measured the signal in the Silicon Valley area.  NBS
> published and distributed the offset.
> Does anybody remember that booklet?  Did I get the story reasonably accurate?

When I was hired by HP in 1979, my new boss (who was the head of the
Precision Frequency Sources R&D section) gave me a tour of the
Santa Clara Division site, including the "Metrology Room" which
was a glassed in area strategically located at the intersection
of the main east-west and north-south corridors in the complex.
Right next to the windows was a rack with several HP 5061A cesium
standards and various other non-descript rack chassis.  There
was also a small TV set that was rack mounted.  This was part
of the system to compare the cesium standards to the TV signal.
My boss described this as "the most accurate clock on the west
coast".  Passersby were invited to set their watch according to
the front panel display on the 5061A.  There was also a 5087A
distribution amplifier that supplied 10 MHz to my R&D section as
well as the various production lines.  This was referred to as
the "house standard".  My memory is a little hazy about the
transition from the TV signal to Loran C, which was fairly new
at that time.  Later, they built a large time display for the
lobby that was synchronized to the 5061A in the metrology room.

Interestingly, the Santa Clara site came with built in wall
clocks that were supposed to be centrally synchronized, as was
common in the 1960's.  These were not connected in any way
to the "most accurate clock on the west coast" and were frequently
off by several minutes and were not even consistent among
themselves.  So the joke was that we had both the most accurate clock 
and the least accurate clock.

Rick Karlquist N6RK

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