"Time" Now That Ceefax Has Ceased To Be
"Time" Now That Ceefax Has Ceased To Be
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GC8

Original Poster:

19,910 posts

212 months

Thursday 2nd January 2014
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As Im sure that many people know, BBC Ceefax time was used as a reference for road rallying.

Now that instant analogue television broadcasting and Ceefax are a thing of the past, what is being used as the time reference now?

Im guessing that it will be a time signal on Radio4 or similar, but Id like to know if anyone can tell me.

thunderbelmont

2,982 posts

246 months

Thursday 2nd January 2014
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GPS Time is far more accurate, and I'd assume that's what they use as not all cellular networks carry "NTP broadcasts" (Network Time Protocol)properly. Unless they pull the time from a DVB signal, which will be GPS based anyway as that's where the transmitters get their signal from to sync the signals.

GPS Time is accurate to something like 10nS ie: 10 billionths of a second.

Also known as a "Shake" in Nuclear circles - short for "One Shake of a Lambs Tail" - the time taken for one generation of nuclear chain reaction using fast neutrons.



GC8

Original Poster:

19,910 posts

212 months

Thursday 2nd January 2014
quotequote all
I new that I was missing the bleeding obvious!

DVB lags quite badly, I believe, but GPS GMT will be ideal. I want to time a box of analogue and digital stopwatches over 12hrs & 24hrs and I have been struggling with lag and latency when using the internet.

Thanks.

Truckosaurus

12,843 posts

306 months

Friday 3rd January 2014
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I once heard "BBC Time" described as "the clock reads 21:00 at some point during the 9 o'clock News".

Slidingpillar

761 posts

158 months

Friday 3rd January 2014
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The only accurate broadcast pips are the R4 LW ones, at 100 miles from Droitwich.

Anywhere else, they'll be received a bit late - they are adjusted to be correct at the NPL in Cambridge.

GC8

Original Poster:

19,910 posts

212 months

Friday 3rd January 2014
quotequote all
Thank you. Im pretty much bang-on 100 miles away from Droitwich. Do you know its only the long wave signal which is accurate and not the FM? I had a car which only had a LW and MW radio in a few years ago and even though R4 LW and R4 FM are substantially different, I thought that they transmitted the same service at news and time signal time?

I have to add that it is consistency that Im after as opposed to absolute accuracy. It doesn't matter if its a few tenths out today, providing that its the same number of tenths out tomorrow too.

velocemitch

4,019 posts

242 months

Friday 3rd January 2014
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In my experience 'Rally Time' is not necessarily linked to BBC time or anything central at all. A simple clock is provided at signing on and everybody sets theirs to that.

Some individual start clocks do have a habit of adopting local time too.... wink

thunderbelmont

2,982 posts

246 months

Sunday 5th January 2014
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Which is why GPS time should be used to ensure that all "clocks" are the same.
You can get serial and USB port GPS receivers and apps to use them to correct the hardware clock on a PC.
They are as cheap as chips.


velocemitch

4,019 posts

242 months

Monday 6th January 2014
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thunderbelmont said:
Which is why GPS time should be used to ensure that all "clocks" are the same.
You can get serial and USB port GPS receivers and apps to use them to correct the hardware clock on a PC.
They are as cheap as chips.
It's not as simple as that I'm afraid.
A; most clocks used are Wharton type clocks which are out of the Ark, some events use Liege timing which is an automatic chip system, I doubt it's been made with that facility, though I could be wrong.

B; you are assuming the organisors actually want all the clocks to be the same.... wink