Radio Controlled Clock

[Radio Fixer]

We needed a kitchen clock (why are they all so big?) and opted for a Habitat one that is radio controlled from an atomic clock somewhere.
Not for the accuracy but just to avoid getting in a large pair of steps to put it right twice a year.  Stupid BST  

It, at first, took an hour or so to get the time set right, which was fine, as it says with the blurb it can take up to 5 hours Ugh!.  But after working properly for a day the time is out by 8 hours or so.  We wait now wait for the 5 days for it to get right again else it goes back.

If it works, well, it is pretty amazing technology as 'HT' is one AA cell.  Its hard to imagine doing circuit design from such a low voltage power source. 

Anyone else got one or the watch version?

Gary

[Mike Watterson]

I have a clock Radio that uses the UK Time signal. Stupidly there is no way to manually set it and it can take several days to update.
Also why do no devices with UK or German time signal reception have:
1) A DST disable switch. Some usages require UTC.
2) A +/- offset switch with maybe 3, 4 or 5 settings. What if you are not on UK or German (CET) timezone?

Penny pinching.

Low voltage? Possible 40+ years ago for 60 kHz or 77kHz and also the logic. Quartz clocks divide from 32768 Hz to 1 Hz on 1V supply.

The UK MSF signal, formerly the Rugby clock is on 60 KHz and now in Anthorn, Cumbria. The other well known one is on 77.5 kHz, DLF77, Located southeast of Frankfurt am Main with a range of up to 2,000 km. So I should be able to get that in Limerick as it's about 1230 km. UK effectively blocked Ireland joining CET permanent Summer Time as we can't have a time border in Ireland, so the scheme to ditch the pointless twice a year time switch adopted in UK & Germany due to the war in 1917 is on hold.

Radio Time clocks maybe also should have a MSF /DLF77 switch? None have. You buy one or the other.

Other time signals:
https://en.wikipedia.org/wiki/Radio_clock

Atomic clocks are now affordable which makes it a risky cost saving using GPS Satellite derived timing for mobile phone masts, DTT, DAB and some internet backbone systems. One decent solar flare and the GPS is gone.

The ZN414 TRF receiver was 1972 and used a 1.5V cell. The 4000 series CMOS was launched in 1968! It could run off 3V. There has been logic that will run off less than 1V for decades.

Oh, and Irish consumers that bought Clock Radio that has DAB and FM? Many only set time by the DAB reception. At best Irish National DAB only had about 45% coverage and closed in May 2021. It was a duplication of Digital Radio on DTT and Satellite and had no local stations.

I now use a Sangean World Radio with a standalone quartz clock as the alarm. Unusually you can use the numeric keypad to type in the time.

[PerdioPal]

I got an analogue German one from Amazon UK (note: UK) it was one hour fast (it set within five minutes) easy solution was to pop the front off and shift the hour hand back an hour.

https://www.123pricecheck.com/p/product/...5qzdw.html

[Mike Watterson]

Anyone else got one or the watch version?

Casio do or did one that works on six frequencies.
https://en.wikipedia.org/wiki/Casio_Wave...lti-Band_6

We have a small LCD temperature display (outdoor part failed) that uses MSF to set the date and time. It seems to take a few hours to lock, much better than the near useless clock-radio. The DAB/FM clock-radio is in the big attic box of Clock-Radios.

[Murphyv310]

Hi
I have a Lidl weather station with radio controlled clock, it sets normally within 10 minutes but can take a little longer on occasions. I also have an analogue radio controlled clock, the hands whizz around for a minute or two then sit at a predetermined time untill the real time synchronises with hands, deadly accurate and occasionally resets over night. I've heard the older clocks actually work better than the modern ones.

[joebog1]

Many years ago I worked for a company called General Electronic Developments. WE made a master clock there, but it was specifically as a master clock and if I remember correctly was tuned to 10.00 megs WWV in Hawaii.
I never knew how much we sold them for, but it would not have been cheap. The local oscillator in that ran inside an oven. The oven was a big 5 watt block resistor, then the crystal body, then an MJE2955 as the current source. It all fitted into the smallest diecast box from Eddystone, which was packed with polystyrene foam. I know NASA had a few of them, as did the CSIRO Division of Radiophysics where I worked later.
They had Nixie display elements, mainly because LEDS were just sticking their heads up.

Joe

[Richard_FM]

I've got an LCD radio controlled clock which usually resets overnight when daylight saving starts & ends.

Occasionally it takes a while when I need to change the batteries, but there is the option to set it manually. Once it must have picked up a stray signal because it was showing the wrong time for no obvious reason.

[DrStrangelove]

I have  a remarkable number of Lidl clocks that use the 77.5 kHz signal.

They all seem to work rather well, though one developed a short on the LCD driver which was rather irritating.

I also have a couple of MSF clocks plus a home made one that eventually emerged when I got a Round Tuit some 30 years after the receiver appeared in "Wireless World".

Compared with the bought versions it's enormous and drives decoder software in a PIC rather than the shedload of ttl in the original articles.

[Radio Fixer]

Thanks for the interesting replies. Looked up the TRF radio chip and lots here:
https://www.cool386.com/zn414/zn414.html

Still seems remarkable to do logic on 1V. Used a lot of Cmos over the years with a normal supply on 5V.

Our clock did come accurate within a few hours and so is a 'keeper'

Gary

Gary

[hamid_1]

I have quite a collection of radio-controlled clocks and watches, and have been using them for many years. They vary in features and quality.

Most of them use the MSF UK transmitter. This normally has good reception day and night. The clock usually acquires the correct time in less than 5 minutes. DCF77 reception from Germany is more difficult in the UK. The signal is usually stronger after dark; you may have to leave your clock overnight to get a signal.

Back in 2005 I built a radio-controlled nixie tube clock from a German kit. It came with a DCF77 receiver module. Unfortunately I couldn't get this to work reliably with the nixie clock. The HV power supply for the nixie tubes is quite noisy which doesn't help. So for the last 17+ years it's been running as a mains-synchronous clock. It's had over 150,000 hours of use and the nixies are still good! The mains frequency varies throughout the day, so the clock may gain or lose up to 30 seconds or so, but this drift is corrected periodically by the electricity company so over the long term it's more accurate than most quartz clocks.

Talking of quartz clocks and watches, most of them have used a single 1.5v battery since the 1970s when mass-produced ones first started to appear. Accuracy is typically +/- 1 second per day. The best ones I've got are about 1 minute per year; some as bad as 10-20 seconds per day. An annoying number of digital watches seem to run slightly too fast, yet the time cannot be adjusted backwards. Whose idea was that?

Radio-controlled LCD clocks and watches usually have an indication on the display to show that a signal is being received. Analogue wall clocks usually don't. Sometimes your clock can't get a good signal where you've placed it. You may have no way of knowing this. I have occasionally had R-C clocks and watches do strange things, like go exactly 1 minute slow, or even show a completely random time. It's rare but be aware that it can happen, maybe due to interference. Surprisingly when this has happened to me, only one of the clocks in the same room was affected.

As I said, there's variation in quality and features. I have a Lidl weather station with radio-controlled clock. Perhaps not surprisingly this defaults to a location in Germany and CET when the batteries are first inserted. It's possible to change it to UK time and location but it's a bit fiddly. The procedure is in the instruction manual. Likewise I have a Casio Wave Ceptor watch that can receive a choice of several different time transmitters around the world. Your exact time zone can be set too. Battery life is surprisingly good - several years life from a lithium button cell. To save battery power, the analogue part does not have a moving seconds hand. The minute hand only moves once every 20 seconds. The MSF wall clocks often have no means of setting the time manually. If you're in a different time zone or can't get a signal, you're out of luck. My Acctim LCD MSF clock has a GMT/CET switch on the back, but that appears to be the only option.

Yes, there are other devices that can auto-set the time by other means (FM RDS, DAB, DTT, Internet). All of these have their pros and cons. And of course they will only work as long as the transmission is maintained. Bad luck to those in Ireland who lost their DAB signal. At least nearly all DAB radios can receive FM broacasts, and some but not all can set the time from FM RDS. I have heard there was some software for Apple mobile phones that could generate the 60KHz signals used by radio-controlled clocks, thus providing another way to auto-set them in case things change in the future. Of course the mobile phone is likely to be obsolete long before then!

On the whole, I like radio-controlled clocks in their various forms. Not having to keep re-setting them is a real boon!