[ntp:questions] Re: questions on msf (via shm) clock
jonathan at uk.me.buzzard
Thu Dec 30 10:54:18 UTC 2004
On Mon, 27 Dec 2004 20:07:27 +0000, dave morgan wrote:
> after a couple of false starts (transistor back to front,
> resistor connected to wrong pins :-/ ) I have got my MSF refclock
> working. This has raised the following questions -
> a) will its jitter figure never go below 1?
>From my machine running the original hardware
remote refid st t when poll reach delay offset jitter
LOCAL(1) LOCAL(1) 10 l 43 64 377 0.000 0.000 0.004
*SHM(0) .MSF. 0 l 36 64 355 0.000 0.183 0.497
> b) why does the refid for this clock show SHM(0), even though the
> lines for it in the ntp.conf file is as follows?
> #msf rx on serial port 1
> server 127.127.28.0 prefer
> fudge 127.127.28.0 stratum 2 time1 0.022 refid MSF
>From memory because you have changed fudged the stratum level.
> c) what stratum should I declare it? I have left it fudged to 2 for
> now as the jitter seems no better than the other stratum 2 servers
> I use.
You should leave it at it's default stratum level of zero. This is because
what you have is a genuine stratum zero reference clock. All hardware
reference clocks that acquire their time from a remote source via radio or
microwaves are by definition stratum zero. Don't be fooled by the fact
that it did not cost very much.
Jonathan A. Buzzard Email: jonathan (at) buzzard.me.uk
Northumberland, United Kingdom. Tel: +44 1661-832195
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