[time-nuts] WWV/CHU

Bob kb8tq kb8tq at n1k.org
Fri Mar 30 10:50:41 EDT 2018


Hi


> On Mar 30, 2018, at 12:42 AM, Hal Murray <hmurray at megapathdsl.net> wrote:
> 
> 
> jimlux at earthlink.net said:
>> Hal, you should know better than to have a question like "get time" on this
>> list without specify the precision and accuracy <grin>..... 
> 
> I was thinking of measuring the results, and maybe comparing various 
> receivers if I get that far.
> 
> "Good enough" for me would be to see the change in prop delay from night to 
> day.
> 
> 
>> I was in a meeting yesterday with a lot of technical people, discussing
>> testing an HF receiver, and I mentioned WWV as a source, and there were  a
>> combination of blank looks and amused/amazed looks (at the blank  looks) -
>> OK, so now we know who in the room are the computer only people  (WWV? is
>> that some sort of NTP protocol?) and who  are the radio people 
> 
> I listened to WWV as a kid.  I think my father told me about it.  (We had a 
> good collection of old tube radios.)
> 
> Roughly 40 years ago, a friend showed me a NBS booklet describing a scheme 
> for distributing time via TV.  I forget the details.  It was a cooperative 
> project with one of the major networks.

Back in the era when the network stations all “went direct” to the mothership for their
signal, all the sync pulses ultimately could be traced back to network HQ. That changed
when local frame buffers (and other forms of translation) became the “way to do it”. The
TV based sync timing survived in the Washington DC area longer than the rest of the
country. It may even still be active …..

Bob


>  NBS published the propagation delays 
> which changed occasionally as the phone companies providing the underlying 
> links rerouted things.
> 
> This is an IEEE article from 1972 that looks like a good fit:
>  Nationwide Precise Time and Frequency
>  Distribution Utilizing an Active Code Within
>       Network Television Broadcasts
>                    DAVID A. HOWE
> https://www.researchgate.net/publication/3092613
> 
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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