[time-nuts] new year crashes
tractorb at ihug.co.nz
Mon Jan 2 05:21:03 EST 2017
The 'landline' networks also have significant (and variable) latency. ISTR measuring a maximum of around 400/500 mSec some years ago on a WN-CH digital link. Minimum over the test period of a week was nearer 250 mSec a few days later.
From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Will Kimber
Sent: Monday, 2 January 2017 1:01 p.m.
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] new year crashes
I have also noted the pips sound different and seem to recall an on air comment about using local time*. The last pip is not always longer.
You have also got to watch out for them using off air Freeview satellite transmissions rebroadcast on normal radio stations!
* Maybe from the Carter Observatory where the old solar transit was.
I'm not suggesting that they use it still.
On 01/02/2017 12:46 PM, Kiwi Geoff wrote:
> Will Kimber <zl1tao at gmx.com> wrote:
>> If you listened to Radio New Zealand National news New Year's day
>> morning you would have heard then stating there will be 7 pips at 1:00pm.
>> However there were only 6 !!! So what happened?
> I was listening to both of the above events too, and agree with your
> comments Will.
> The following is just my "observations" over the last few years as a
> keen RNZ listener, and so may not be correct to those in the know.
> To my ears, there are two "types" of Time Pips:
> The "normal" time pips sound like reasonably pure sine-waves of 1KHz,
> and are always correct to my house standard, and would be derived from
> the atomic clocks at:
> Measurement Standards Laboratory
> Callaghan Innovation
> PO Box 31 310
> Lower Hutt 5040
> New Zealand
> The "other" time pips sound different, they appear to be shorter in
> duration and more like a square-wave at 1KHz than a sine-wave. I
> assume they are locally generated at RNZ and are used when the
> land-line to Lower Hutt is broken by road-works, earthquakes, or a
> digger driver with a careless hand !
> In the past I have detected the "other" time pips drifting by about
> half a second per day, so I assume it's a relatively simple XO that is
> used rather than a GPS which I thought would have been a better option
> for a standby reference.
> So my guess as to what is currently going on (for RNZ time pips) is
> that they are using the backup system , which appears to be manually
> set - and is yet to be manually set by a man!
> Maybe someone who knows someone in RNZ engineering, can give a more
> accurate picture than just my conjecture.
> Regards, Geoff ( Christchurch, New Zealand ).
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