Radio controlled clock question

The MSF transmitter at Rugby provides a time signal service on a very low (60kHz) frequency from a highly accurate atomic clock.

IIRC, the time data are transmitted once per minute so it should not take more than a couple of minutes for the clock to synchronise. It's up to the clock to decide how it uses the signal, and it may choose to compare successive time codes before changing anything to reduce the risk that interference affects the setting.

The signal is susceptible to local interference and the level may be low if you are a long way away. However it should be OK over most of the UK.

You could try taking the clock outside on the side of the house that faces in the direction of Rugby and you could also try rotating the clock. Depending on the design, the built in antenna may be directional.

It may simply be that the problem is in your first sentence ("cheap" and "Littlewoods") and you have a second dud clock.....

.andy

To email, substitute .nospam with .gl

Mark

are the minutes correct?......if so you may need to manually adjust for time zone.

continuous, it

I did wonder if perhaps I'm in an area where the signal's not getting through but I did try it during the 5 mile trip home in the car and still no update! Can't see that I'm doing anything wrong, Just press the receiving button to start a forced update. The instructions say the RCC symbol will flash for a maximum of 8 minutes and if signal is successful it will update the clock and the RCC symbol will become stationary - otherwise the RCC symbol will be off (which mine is after the maximum 8 minutes of trying). I will have a read up on the Rugby transmitter.

In article , Andy Hall writes

I have got an Oregon Scientific MSF alarm clock, and it will only pick up MSF in certain areas of the house. My bedside table is a place it does not work! 10cm either way and it works. I would try leaving it in different places in the house, you will probably find the place you have it now is in an MSF "dead spot" or there is too much interference there.

very low frequency.I believe it is continuous, it

No, it just starts from the default 12 o'clock settings. I even tried manually adjusting the clock to close to the right time to give it a helping hand but it still refuses to budge on its own.

I changed the batteries in my r/c clock last weekend & it took a few hours before it picked up the Rugby signal. It tries to sync every hour. Just leave it near a window overnight & forget about it.

JW

I've got one on which you need to set the time manually to the nearest hour before the current time and then it adjusts itself on the next time pulse. It's quite uncanny to watch the second hand moving round on the time pips and hitting the 12 spot on

On 17 Oct 2003, Mark wrote

-snip-

I suspect that out of sheer rotten luck you've hit an outage during the annual maintenance period -- my bedside clock hasn't updated since about 9 am this morning.

This shouldn't last more than a day, though: take a look at the NPL outages page at

Usually during annual maintenance periods it is likely that the service will be interrupted, although these outages will be kept to a minimum. The service is restored overnight between 2000 BST and 0800 BST whenever possible.

So: leave it overnight, and see if it picks up the signal.

HTH

I'll give it till tomorrow and get a refund if now't happens.

It's possible it's not receiving the signal. Mine shows a steady 'receive' indication when things are ok, flashes when it's not happy, and goes out completely when the signal is lost.

I'd say mine is sited well to receive an LF signal but still shows no signal at times - perhaps you could try moving yours to see if it works ok elsewhere.

On 17 Oct 2003, Mark wrote

Sounds wise.

Given the "outages" link in my other post and my clock's failure to reset itself, it would be interesting to know if anyone has successfully had a radio-controlled clock reset itself since around 9 this morning.

Yes thanks for the link. Looks like problems solved. Still no update but I rang the number on the NPL site and a recorded message confirmed the MSF signal was down from 9am 6th Oct until 9am 20th Oct, but will be working overnight whenever possible.

On 17 Oct 2003, Mark wrote

Excellent -- I hope mine updates as well!

The Rugby transmitter sends a continuous time signal. It takes exactly one minute to send the time *once*. Most clocks try to receive two or three consecutive signals, with time values that differ by one minute, before they commit to updating the clock itself. So, a weak signal can mean they don't ever update, and even a string one will take three or four minutes.

Bear in mind this is long wave. It's subsceptible to nearby metallic objects, so try moving the clock around the room and trying again. Try it upstairs too. Some of them have pretty useless antenna systems.

Try also taking it upstairs!

Being low frequency it won't have a problem going round corners because the signal bounces off the upper atmosphere, whereas with high frequency (FM, VHF, TV etc) you have to have line of sight.

They use low frequency to communicate with submarines on the other side of the world from Northwood in north London (the signal might go out from Rugby though - I don't know the details). A sub can receive signals at periscope depth, as happened in the Falklands when HMS Conqueror was told to take out Belgrano by Northwood (the instruction was issued from Downing Street).

Leastways, that's what was explained to me a few years back. So if I'm right then the submarine will always have an accurate clock.... :)

I've got one of those radio clocks sitting on my desk. Every so often the receiving signal flashes for a period of time when it updates itself. I don't have a problem with the clock being wrong.

Are you sure you haven't got it set to some other time zone? You need GMT in the UK.

PoP

On 17 Oct 2003, PoP wrote

-snip-

Are you sure it's been able to reset itself during the day, today?

As noted in my other posts, the NPL site says the Rugby transmitter is on annual maintenance from 6 to 20 October, with signal transmission probably out from 9 am to 9 pm. (There's an indicator on my clock that shows if the hourly update was successful, and if not how many hours it's been since the last update was made: that's now sitting at 8 hours missed, and since it's currently 17:30, it must have last updated at 8 am, in line with what the NPL site says.)

The signal is transmitted at 1 bit per second, represented by a 100ms or 200ms break in the carrier IIRC. I built a rugby clock receiver about 12 years ago, together with a driver for Interactive UNIX for it to keep the system clock in sync. If you arrange for the breaks in the carrier to cause an audiable tone, it's quite easy to decode it by ear. I sat up on a few occasions to listen to it handling the daylight savings shift (not sure I should admit things like this;-).

For some years (certainly when I built my receiver 12 years ago), there was also a fastcode transmission in the last second of each minute which encoded much (maybe all) of the data again within that second. I vaguely recall hearing they have since dropped the fastcode transmission.