[time-nuts] ABC time signals in Tasmania/Australia wrong

Joe McElvenney ximac at btinternet.com
Sun Jan 3 14:44:43 UTC 2010


Hi,

I don't know whether the ABC signal you are referring to is TV, AM, FM
or DAB but, if it is digitally networked, it isn't uncommon for time
signals to be out by a second or so. Before Christmas, here in Sheffield
(UK), the digital clock on my bedside DAB radio was well over seven
seconds slow but suddenly 'pulled-in' to about two or so. When I first
got the radio, I rang the local manufacturer's 'Help Line' to be given
the two-word answer "Network Delays".

Some of these will be unavoidable but I seem to remember reading that
they are also something to do with synchronisation of, or preventing
interference from, multiplexes in nearby areas. It would be nice if the
offset were constant though but perhaps is set dynamically. First off I
wondered if they couldn't have preset the local transmitter clock to
take this into account but realised that it would then insert the 'pips'
at the wrong place in the audio stream. Still, if they can put GPS
disciplined clocks at mobile phone sites, they should be able to set the
local time bytes to better than two seconds.

If someone has more information on this I would like to hear it? A few
years back you could email the BBC engineering department but now it's
all out to contract and I've no idea who to ask.


Cheers - Joe G3LLV



Date: Sun, 3 Jan 2010 19:02:18 +1100
From: "Morris Odell" <vilgotch at bigpond.net.au>
Subject: Re: [time-nuts] ABC time signals in Tasmania/Australia wrong
To: <time-nuts at febo.com>
Message-ID: <000001ca8c4b$11f5fcd0$35e1f670$@net.au>
Content-Type: text/plain;    charset="us-ascii"

They appear to be spot-on here in Melbourne.

Morris


Date: Sun, 3 Jan 2010 12:14:05 +1100
From: Jim Palfreyman <jim77742 at gmail.com>
Subject: [time-nuts] ABC time signals in Tasmania/Australia wrong

For the Down Under nuts,

The ABC radio time signals in Hobart are one second out. Is it a
national
thing? Can others in the country check?

I rang the ABC locally on xmas eve but it is still not fixed.

Jim Palfreyman





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