[time-nuts] WWVB format change in 2012

[Tim Shoppa]

Having a diversity of refclocks is important for any real NTP
implementation. There is a strong tendency towards a GPS monoculture and
the implementers must work against it.

Support for WWV in ntpd using the wwv_audio refclock is very good and
delivers jitters substantially less than a millisecond. I have been using
this for over a decade.

ntpd also supports CHU.

Here is a recent article showing how to use the BPSK format of WWVB:
http://www.arrl.org/files/file/QEX_Next_Issue/2015/Nov-Dec_2015/Magliacane.pdf

Tim N3QE

On Sun, 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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