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

Tom Van Baak tvb at LeapSecond.com
Thu Nov 12 10:03:39 EST 2015


And the decade before that the hp house standard looked like this:



----- Original Message ----- 
From: "Richard (Rick) Karlquist" <richard at karlquist.com>
To: "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Cc: <hmurray at megapathdsl.net>
Sent: Thursday, November 12, 2015 6:23 AM
Subject: Re: [time-nuts] Time syncing WiFi routers using FM radio

> 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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