Putting the clocks back

There's a few interesting clocks to be seen in this article about putting the clocks back at Windsor Castle.

With the clocks going back tonight (02.00 hrs) I woke yesterday morning and the bedside alarm radio had reset itself one hour behind, creepy as the clocks don’t change until tonight. The clock in question is one set by a radio signal so should always be right, I switched it off yesterday to allow a reset when I switched it back on, however it reset to minus one hour again so I am leaving it as is to see what it does tonight when it should reset by radio signal to winter time. Anyone else had their radio signal clocks misbehave.
Dave W

I've just stopped all my pendulum clocks and will restart them in the morning.

Martin P

Put mine back this morning

Jim

Further to my post above about my clock putting itself back 2 days early, this morning it was functioning as it should showing correct time and the alarm went off as normal, very strange.
Dave W

Just for convenient reference: **LINK**

https://www.npl.co.uk/msf-signal

MichaelG.

We have one of those radio-controlled clocks. It copes fine with the change of hour, but has been consistently four minutes slow for years. No idea how that happens.

Pete

Using the beacon on Mars?

pgk

Some clocks and watches sold in the UK use DCF77 from Mainflingen,Germany.

.

Yes ... but I don’t currently have a ‘convenient reference’ for DCF77

Do you ?

MichaelG.

Same thing happens across the pond. It will miss one time change then make it up some other time. We have to use the phone alarm to be sure.

Peter, is it an analogue display? Maybe the hour hand is displaced.

Yesterday morning one of our "weather stations", the older one in the kitchen, seemed to have shifted 2 hours and now won't synchronise at all. It must be 20 years old so something has probably died. The other one, an update of the same model with a colour display, is fine. My radio controlled alarm clock didn't change its time and doesn't have a manual set function, but overnight has got back in sync.

.

Exactly my first thought, John

@Peter : Simple to check ... the hands should be aligned at 12 [noon or midnight]

MichaelG.

Nope. Digital display.

Pete

I've just spoken to Mrs Hall about this. Apparently her mother has two more, which are also 5 minutes slow. She thinks she may have bought them at the same time, so possibly a faulty batch? It doesn't bother us. Ours lives in the spare room.

Pete

.

Thanks for the clarification, Pete

The likelihood of finding/fixing a digital fault is small ... but, for anyone who wants to play:

There’s an explanation of the data structure in a link from that NPL page I referenced yesterday.

MichaelG.

I suspect the clocks are getting a poor signal, perhaps the antenna isn't optimally aligned, or the clock is shielded by metal in the building, or power lines outside, or suffers from local interference. Domestic radio clocks go for a small internal ferrite rod antenna with a simple receiver; a bit deaf and liable to pick up nearby noise. Professional clocks have better receivers and an efficient external antenna - typically mounted outside and clear of the electrical fog found in most homes.

The nature of the signal may explain why the clock is minutes out. Second and Minute markers are ON/OFF obvious, while the other information is encoded. A clock subject to interference could struggle with the decode part whilst having no bother spotting minute ticks, without knowing how far past the hour each is.

The encoded data is repeated, making it possible for radio clocks to gradually build up correct readings but much depends on the sophistication of their software. Simple clocks may fail while a clever clock recovers the answer quickly. Pete might try taking his clock outside and hold it up for 30 minutes with the face looking towards Cumbria. If it corrects then poor signal is confirmed.

My mobile phone only works outside or if I stand in the bath...

Dave

I have a couple of these radio controlled clocks which worked fine for a few years then one of them started to slowly gain about two seconds a month and refused to change time when the clocks changed. I tried moving the clock into various locations and changed the batteries but nothing would make it work properly. On the point of throwing it out I tried one last location on the roof of my outside workshop. Next morning the clock had adjusted itself correctly, but I have to do this every 6 months to keep the right time.

Doug

When digital tv was introduced into the UK we displayed the time on the box but left it to customers to make the change. After grumbling that autumn we put an automatic change in the operating system. However the higher level programmers also put a change in so in the spring 2001 it changed by 2 hours!. We did a lot of testing before the autumn.

When we obtained equipment from the USA I had to detail the checks the software had to perform, about 22 stages I recall, like the Americans had never heard of it before to work out what to do themselves. Interetingly the Uk does the actual change at a different time in the early morning to Europe and of course most of the world doesn't change anyway and Australia goes in the wrong direction and two weeks earlier than us.

How about this: **LINK**