Radio 4 time code.

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dr pepper

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Sep 24, 2013, 3:05:17 PM9/24/13
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A question for those of us in the UK.

I allready have a frequency standard that uses radio 4 on long wave to synchronise to, however the carrier has phase modulated data on it, I believe this is used by the power companys to control heating and the likes.
Does this signal contain the time of day, and any info on how the protocol works?

Grahame Marsh

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Sep 24, 2013, 3:40:15 PM9/24/13
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Yep, it carries a lot of information including date/time, try this link

http://www.freescale.com/files/microcontrollers/doc/app_note/AN1597.pdf

searching on "198khz phase modulation" will hit a lot of related sites.

But I believe, like most AM services, the Beeb Radio 4 LW is doomed...

Grahame
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dr pepper

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Sep 25, 2013, 12:55:22 PM9/25/13
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Yes of course a pll, my standard allready has one locked to the carrier.
I could incorporate another with a much quicker loop filter response to detect the phase changes.

I agree and disagree about the 'doomed' situation.

Some FM stations from the BBC are certainly pending 'doomdom', allthough due to demand they have suspended this.
Most of the AM stations that are going have gone, the rest are due to stay.
The beeb has no intentions of discontinuing radio 4 on long wave, what they said was the valves used in the transmitter are no longer manufacturer and it would cost too much to replace the transmitter, so when it goes down its gone, but it could last 10 years, by which time some cheap import transmitter may well be available.
R4 lw is used by lots of folk.

MrNixie (UK)

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Sep 26, 2013, 5:03:10 AM9/26/13
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Yes, I believe a still HUGE number of ECONOMY7 electricity meters up and down the UK use the Radio4 timecode signal to switch between rates. They'd all need replacing if the LW signal went down. Of course, this will come to pass once we all have Smart Meters, but don't hold your breath for that one!

Nick

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Sep 26, 2013, 5:55:24 AM9/26/13
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John Rehwinkel

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Sep 26, 2013, 10:16:34 AM9/26/13
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> http://www.elexon.co.uk/wp-content/uploads/2012/07/BBC-Letter-John-Mottram-180712.pdf

Ah, Radio 4 is broadcast out of Droitwich. That station first came on the air in October 1934, to improve the quality and coverage of the BBC longwave service. It used a "T" aerial strung between 700 foot masts, powered by six Marconi-Osram CAT14 valves operating in push-pull with 20kV anode potential.

They put out a brochure in 1994 called "Droitwich calling", giving the history of the station.

- John

Grahame Marsh

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Sep 26, 2013, 10:53:58 AM9/26/13
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On 26/09/2013 15:16, John Rehwinkel wrote:

Ah, Radio 4 is broadcast out of Droitwich. That station first came on the air in October 1934, to improve the quality and coverage of the BBC longwave service. It used a "T" aerial strung between 700 foot masts, powered by six Marconi-Osram CAT14 valves operating in push-pull with 20kV anode potential.

They put out a brochure in 1994 called "Droitwich calling", giving the history of the station.

- John

Perhaps?

www.bbceng.info/Operations/transmitter_ops/Reminiscences/Droitwich/droitwich_calling2.pdf



dr pepper

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Oct 15, 2013, 2:07:21 PM10/15/13
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Thanks for the replies.

At one time we were a proud nation, now its a case of in it for the readies.

looks like we'll be having radio 4 for the next 3 years then.

There are 2 other transmitters for radio 4 in scotland, they are synced to the same rubidium source, I take it if the main xmiter goes down they'll shut these too.

I've been researching and found some data on radio france, also on lw, it transmitts phase modulated time data too, and its synced to a caesium fountain resonator, I found a schematic to strip the data bits from the carrier, the encoding is similar to dcf77. I think I'll look into this, radio france doesnt have any sob stories about shutting down.


On Tuesday, 24 September 2013 20:05:17 UTC+1, dr pepper wrote:
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