[time-nuts] WWVB format change in 2012

[Bob Camp]

Hi


Ok, I think we have a bit of a terminology issue here. 

The new WWVB format is troublesome for older gear that looks at carrier 
phase as a source of precision timing. The NTP driver does not do this.

The new WWVB format is fine for any gear that recovers time from the 
AM modulation on the carrier. This is what the NTP driver *does* do. 

Simply put - WWVB and NTP work just as well today as they did 20 years
ago. 

As a “future project”, adding a driver to NTP to work with the bitstream from 
the new phase modulation would be a nice thing. At the moment the number
of receivers capable of handling this modulation is pretty small. I would 
wait until there is at least one commercial product on the market before
a driver is written.

Bob

> On Feb 28, 2016, at 2:09 AM, Sanjeev Gupta <ghane0 at gmail.com> wrote:
> 
> Hi,
> 
> I am reviewing and expanding and for the NTPSec project <
> http://www.ntpsec.org >, a fork of NTP.
> 
> Among NTPSec's goals are a smaller, auditable, code-base; hence support for
> receivers last available in the early-1990s is being removed.
> 
> I have been on this list for some years (thank you), but as I am in
> Singapore, I did not pay attention to the WWVB format change.  I understand
> that as a result of the change, precision equipment may not be able to
> recover a usable signal from the new modulation scheme, rendering it
> useless for the sub-100 microsec disciplining.
> 
> However, I am not clear if WWV and WWVH are still usable by commercially
> available equipment, or of such equipment is also obsolete now.
> 
> I have read Wikipedia, the NIST pages, etc, and am still confused.  Could
> someone summarise current state:
> 
> 
>   1. Are there commercially (or widely-used) receivers for professional
>   use which listen to the WWVB signal?
>   2. Are there commercially (or widely-used) receivers for professional
>   use which listen to the WWV(H) signal?
> 
> A supplementary question: If you have your own homebrew for these signals,
> do you use them as a refclock for NTP?
> 
> Thank you
> 
> 
> -- 
> Sanjeev Gupta
> +65 98551208     http://www.linkedin.com/in/ghane
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