A discursive look at Napoleonic & ECW wargaming, plus a load of old Hooptedoodle on this & that


Tuesday, 12 March 2019

Hooptedoodle #326 - Missing Pips - Today's Pointless Conundrum

This is a puzzle that occurs to me at almost exactly 7am each day. Just how exactly is, I guess, the essence of the puzzle.


I have a digital radio next to my bed (it's actually the one that used to be in the kitchen, until the volume knob became temperamental - you know how it goes). At 6am each day it switches on BBC Radio 4 - the "Today" programme on weekdays - so that I may update myself on the latest glories of Brexit and Trump and all the other things which guarantee that I may start my day as depressed as possible. At 7am it switches off - the assumption being that either I'm already up and functioning, or else I have probably had enough delight and happiness for one morning.

The reality, of course, is that I have set the menu on the radio so that BBC R4 will come on at 06:00 and switch off at 07:00. The radio knows what time it is because the exact time is transmitted constantly along with the programme signal - so you would expect that to be pretty accurate. I mean, we are speaking of the speed of light here.

Astonishing, really - in the digital age we just expect everything to be spot on. It's worth remembering that it was only the coming of the railways which necessitated some standardisation of clocks throughout Britain, and, before that, the coming of scheduled stagecoaches was a big push towards standardisation of the calendar - prior to that it didn't matter a huge amount if your village had a different date from the village down the road. Now we have so much accuracy we can't even remember why it's important.

I digressed there - sorry.

The point of my post is that each morning the radio switches itself off just as the "pips" of the time signal are being broadcast. I don't know much about the pips, really, except that they've always been part of listening to the radio - even when it was a wireless. Six pips - 5 short ones and a long one - like this...


Originally, I think these were generated by the Greenwich observatory, but for the past 30 years or so they have just been a service provided by the BBC - they are timed exactly so that the long final pip indicates the start of the next hour.

Here's the 8am signal - impressively accurate
Because my radio is busy switching itself off at just about the time the BBC are broadcasting the 7-o'clock pips, I only hear the start of the sequence - I never hear the sixth pip. OK - we may debate accuracy and stuff like that, but the number of pips I hear before the radio cuts out varies. Yes - that's right - calm yourself now - I don't think it's anything to worry about, but the number of pips I get to hear varies mostly (randomly) between two and four - very rarely five. Never six. The BBC, which ensures accurate precision of the timing of the sixth pip and which broadcasts the time continuously so that my radio knows exactly where we are up to - yes, that BBC - manages to either fool my radio very slightly or get the timing of the audio signal slightly wrong - maybe both - every morning.


A couple of seconds is near enough for me, of course, but I don't really see how this works. Is it possible that there is some buffering or delay in the programme transmission? - I have occasionally noticed that if you switch two DAB radios to the same station they may not be quite in sync - this is especially true, I find, if you listen to the digital radio service on your TV at the same time as the same station is connected via the DAB unit.

Anyone understand how this works? Is it possible that the BBC are going to the trouble of broadcasting an exact time signal which isn't actually accurate by the time it reaches the listener? Imagine the potential chaos - stagecoaches could be crashing into each other at crossroads all over the country.

Disaster.

It'll all end in tears

Anyone know how this works? 

26 comments:

  1. I'm sure the clock signal comes form Rugby??? Not sure why? I could be wrong though..........probably am?

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    1. Hi Ray - yes, that's right - that's where they generate the signal for all the radio-controlled clocks.

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  2. DAB signals are encoded and compressed. The delay relative to the clocks radio reflects the time taken to decode and decompress. Or so says the internet anyway...

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    1. Ivan - thank you for this - a bit of science - that's what we need. That sheds a little light, and is very reasonable. It does put a whole new slant on any idea of precision though. Interesting - just suppose (just suppose) the BBC have some contractual obligation to use accurate timings, and to transmit the national time signal - if they do that correctly, but for various technical reasons the accuracy is lost before the listeners get to hear it, does anyone care? If a stagecoach crashes in the forest, but the BBC doesn't know about it, does it make a sound? Hmmmm.

      For some reason this reminds me of a newspaper article I read about a Japanese family who received a letter dated 1944, telling them that their son had lost his life in the service of the Emperor on some recent date. The letter was finally delivered to them in 1996.

      My son used to do maths homework involving radio signals being sent to rocket ships travelling at large fractions of the speed of light. Perhaps if I listen to Radio 4 for long enough I will be younger than I would have been otherwise? Nah - older - it has to be older. It feels like older.

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    2. sorry, that should have said 'the radio's internal clock'. science is hard - no wonder only the best went from West Point into Artillery! and thank goodness for 'bounce sticks'. Re: precision vs. accuracy. your clock alarm radio is precise. It's just not accurate.

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  3. I listen to Wireless 4 in the morning too, but it can be a little like the Home Counties Broadcasting Company. I suspect changing weather conditions on the A1, together with the fact that it's all uphill is the cause of the fluctuating delay in you receiving the signal. Of course I never did understand technology. I am impressed that you can time your wireless to go off on its own, without having to give it a whack with a carpet slipper.

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    1. Not true, there’s a rich diversity of regional accents on the BBC (though maybe not on 4 at 7am). Do love the idea of the signal traveling uphill though....maybe if the transmitter was moved to Scapa, Foy would have a more accurate pip signal. Or maybe early? Flowing downhill and all. By the same token though, would folks in the Home Counties be on time, or slightly late getting up?

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    2. Ah yes - regional accents - London, of course, is not a region. I think Radio 4's programming - or at least a lot of it - is now based in Salford.

      The early signal is a good idea - if the downhill flow was in the right direction, I might get to hear what John Edmunds had to say before he said it - in fact he could phone me up to check what it was he was going to say. Useful.

      The "regional" bit is not a problem - since Edmunds comes from Wales and Nick Robinson is a Mancunian, the Today program is already a good mixture, and even Justin Webb is from Portsmouth, which must be regional, you would think. All that is OK - what makes people fed up is when the weather lady comes on and tells us that it's going to be a lovely day for us all - of course, there are blizzards expected in the Lake District and the Scottish Borders, but the REAL weather is going to be fine. Now that is tiresome, even when you have come to expect it.

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    3. Chris - the carpet slipper trick - even though I don't need to switch the radio off by this means, I am still likely to throw the odd slipper or cup of tea during the parliamentary summary.

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    4. Ivan - people being late in the Home Counties - I had another think about that; if they left home when the BBC told them, then - as long as the local transport services and their own bosses also used the BBC (and had the same make of radio?) - they would probably be OK. We've undone the global view of time, but it doesn't really matter.

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    5. Edmunds? Not Humphreys? Bring back Wilfred Pickles I say. A proper accent.
      I think the Parliament programme gets off lightly if you only throw carpet slippers at it.

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    6. Ah, weather forecasts. I'd always assumed people in Scotland got their weather from the Shipping forecast...isn't that what it's for? But don't feel bad; my local radio station provides detailed forecasts for Kalamazoo, Cass, and Berien counties. Those of us in Calhoun co. are simply expected to listen and extrapolate based on prior history.

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    7. Chris - ah yes - Humphreys - bugger. John Edmunds is an old friend of mine, but he has **** all to do with the BBC. Sorry about that. Took my eye off the ball there.

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    8. Shipping forecasts are terrifying - I think the whole thing may be an extravagant joke - the BBC staff are bored last thing at night, so they just make up a lot of junk - "South Undies - falling - backing heliotope, 7 to 11, obscure - fair to middling." The guys place bets as to who gets the most stupid joke accepted.

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  4. I've noticed when I have a "real" radio on in another room that the digital one is a couple of seconds behind it. Which makes a mockery of the idea of an accurate time signal ...

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    1. Agreed - even two DAB radios can be out of sync - one way of generating a reverb effect for really important news. I guess it is reasonable that different devices might take different times to do the decompression job that I just found out about.

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  5. I cannot pretend to understand any of this new-fangled digital stuff, but I really miss hearing the time pips and Lily Bolero at the top of each hour on the World Service before ol' Auntie Beeb made its distinct move away from all things distinctly British near the end of the 90s in an attempt to be more relevant and global in outlook. Sad really. I always felt like the powers that be, or were, at Bush House threw out the baby with the bathwater on that one.

    Best Regards,

    Stokes

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    1. It is nice to have some traditions. The BBC are twitchy these days because their traditional role of maintaining a healthy scepticism is heavily undermined by fear that the right-wingers in the Government are going to cut their funding if they don't toe the line.

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  6. That's another post that could really only come from you Tony, you made us both laugh as I read it out to my wife :) Must be 20 years since I last heard the morning radio pips, never gave them another thought until now.Thanks for that.

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    1. Hi Lee - I just write them as I see them, squire. Hope things good with you and your lot - best wishes to all.

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  7. I miss the BBC pips. Our alarm is set to ABC Radio (specifically 97.3 ABC Illawarra), so this is what *we* get just before the hourly news-broadcast:

    https://www.youtube.com/watch?v=xT0BB98aIQM

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    1. Good grief KK - I played the clip - if that came on the radio when I was still in bed I'd have to leap out and stand to attention. Impressive - very imperial?

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    2. Crikey, it's no wonder they're good at cricket. Positively rippling with early starts, fresh vistas and Muscular Christianity. Could be a theme tune for a Ripping Yarns episode.

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  8. Our public broadcaster used to give a time signal just once a day but now you mention it I haven't heard it in ages, they may have given it up, it wasn't digital anyway.

    Anyway, since we are 5 time zones wide it was never really accurate for everyone, If you lived near the border between time zones, you could have tuned in two different CBC stations each in a different time one and got both signals, an hour apart.

    Of course since the earth turns, time isn't the same in any 2 places anyway, that's why we had navigational books that helped calculate the exact time of sunrise and sunset etc precisely where you are so you could double check your reckoning. Well, not precisely since being even 100 yards away from a given position can change the time by a millisecond or so, but close enough.

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    1. Excellent comment - educational. I'm a bit confused by the idea of the exact time where you are at that instant. Does anyone actually have a clock which shows the exact time where they are? - and if they do, how do they discuss the time with someone who is some distance away? - and (since I'm on a roll here) how do they work out how long it takes to get anywhere? I'm just too dumb to understand this stuff, but it fascinates me.

      A propos of nothing, I used to have a friend who kept his watch on UK time when he visited the USA, because he reckoned that for short visits it saved him getting jet lag - he must have been looking for meals at very odd times.

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    2. Prof De Vries emailed to point out that a great many people (potentially) have clocks which show the correct local time - people who live in Greenwich, for a start (provided they don't set them by the BBC).

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