OT: radio controlled clock

[Scott]

Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I
am guessing it lost its signal during the journey. Two things puzzle
me here:

1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then
set the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?

It has now recovered so I am assuming the battery and the mechanism in
general are okay.

[Mark Carver]

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I
am guessing it lost its signal during the journey. Two things puzzle
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then
set the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

Funny you should say that, last night at 10pm I noticed our MSF kitchen
clock was exactly two hours fast !

I assumed it needed a new battery, so I thought I'd sort it out this
morning.

This morning (at 6am) it was displaying the correct time again.

I wonder if something at Anthorn had a glitch ?

[Woody]

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I
am guessing it lost its signal during the journey. Two things puzzle
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then
set the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

If your battery is dying the radio will stop working long before the
rest of the clock (same goes for radio thermometers as well.) If you
re-power the clock it will wind the fingers in normal clock fashion to
12:00, then when the receiver kicks in - usually after about 2-3 minutes
- it will wind round to the current time. The second hand will sync with
the radio immediately it syncs as that hand is managed independently of
the clock mechanism.

The only other question that comes to mind is whether the clock is
running off DCF in which case there should be a system setting within
the clock to add or subtract time-shift hours which for DCF would be one
hour negative. There may also be an independent DST switch, which could
account for the two hour error. Having said that these last two points
will usually only apply to digital clocks.

[Scott]

Post by Woody

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I
am guessing it lost its signal during the journey. Two things puzzle
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then
set the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

If your battery is dying the radio will stop working long before the
rest of the clock (same goes for radio thermometers as well.) If you
re-power the clock it will wind the fingers in normal clock fashion to
12:00, then when the receiver kicks in - usually after about 2-3 minutes
- it will wind round to the current time. The second hand will sync with
the radio immediately it syncs as that hand is managed independently of
the clock mechanism.
The only other question that comes to mind is whether the clock is
running off DCF in which case there should be a system setting within
the clock to add or subtract time-shift hours which for DCF would be one
hour negative. There may also be an independent DST switch, which could
account for the two hour error. Having said that these last two points
will usually only apply to digital clocks.

See Mark's post which muddies the water considerably.

[Mark Carver]

Post by Scott

Post by Woody

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I
am guessing it lost its signal during the journey. Two things puzzle
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then
set the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

If your battery is dying the radio will stop working long before the
rest of the clock (same goes for radio thermometers as well.) If you
re-power the clock it will wind the fingers in normal clock fashion to
12:00, then when the receiver kicks in - usually after about 2-3 minutes
- it will wind round to the current time. The second hand will sync with
the radio immediately it syncs as that hand is managed independently of
the clock mechanism.
The only other question that comes to mind is whether the clock is
running off DCF in which case there should be a system setting within
the clock to add or subtract time-shift hours which for DCF would be one
hour negative. There may also be an independent DST switch, which could
account for the two hour error. Having said that these last two points
will usually only apply to digital clocks.

See Mark's post which muddies the water considerably.

Is your clock DCF (Frankfurt) or MSF (Anthorn) ?

[Scott]

On Mon, 16 Jan 2023 18:49:45 +0000, Mark Carver

Post by Mark Carver

Post by Scott

Post by Woody

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I
am guessing it lost its signal during the journey. Two things puzzle
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then
set the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

If your battery is dying the radio will stop working long before the
rest of the clock (same goes for radio thermometers as well.) If you
re-power the clock it will wind the fingers in normal clock fashion to
12:00, then when the receiver kicks in - usually after about 2-3 minutes
- it will wind round to the current time. The second hand will sync with
the radio immediately it syncs as that hand is managed independently of
the clock mechanism.
The only other question that comes to mind is whether the clock is
running off DCF in which case there should be a system setting within
the clock to add or subtract time-shift hours which for DCF would be one
hour negative. There may also be an independent DST switch, which could
account for the two hour error. Having said that these last two points
will usually only apply to digital clocks.

See Mark's post which muddies the water considerably.

Is your clock DCF (Frankfurt) or MSF (Anthorn) ?

MSF (Anthorn)

[jon]

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I am
guessing it lost its signal during the journey. Two things puzzle me
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then set
the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

Was moved faster than light..

[Scott]

Post by jon

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I am
guessing it lost its signal during the journey. Two things puzzle me
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then set
the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

Was moved faster than light.

You have been in my car then !!!

[Brian Gaff]

Yes well, they are not the fastest data devices in the world. I have a
relatively new one here and it can sometimes take several hours to get its
self sorted. I don't know hat the bit rate is to set these things but it has
to be slow.
Brian
--
--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
***@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I
am guessing it lost its signal during the journey. Two things puzzle
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.
2. I thought the control process first took the clock to 12:00 then
set the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

[Brian Gregory]

Post by Scott
Last night my radio controlled alarm clock was exactly two hours slow.
I previously lent it to a friend, then took it home in the my car. I
am guessing it lost its signal during the journey. Two things puzzle
1. I thought if a radio controlled clock lost signal it would keep
running until a new signal was found.

The error detection and correction on the protocols they use was
designed a long time ago and is very crude. This means there is a
relatively high chance of interference or weak signal causing the clock
to set itself incorrectly.

Since the data is transmitted in binary coded decimal common errors are
1, 2, 4, 8, 10, 20, or 40 minutes or hours (and days and months on
clocks that have those) or, more rarely, two or more of these at once.

Post by Scott
2. I thought the control process first took the clock to 12:00 then
set the hour hand then set the minute hand. How come the minutes were
showing exactly correct but the hour was two hours out?

The going to a certain time first is normally just the clocks way of
knowing where it's hands are after losing power. It shouldn't need to do
it again unless it loses power again.

Post by Scott
It has now recovered so I am assuming the battery and the mechanism in
general are okay.

Yes, almost definitely.

[Paul Ratcliffe]

On Tue, 17 Jan 2023 21:22:32 +0000, Brian Gregory

Post by Brian Gregory
The error detection and correction on the protocols they use was
designed a long time ago and is very crude. This means there is a
relatively high chance of interference or weak signal causing the clock
to set itself incorrectly.

There is no error correction, only detection using parity.

The data rate is 118 bits per minute:
8 bits are used for framing
4 bits are used for parity
53 bits are used for data
53 bits are unused (currently)

Any decent controller should at least wait for error-free consistent
data for at least 2 complete minutes before setting the clock.
That catches most of the errors that the parity checks don't.
That's what I did in my software anyway, way back when I wrote it
for the Maplin receiver module.

[Scott]

On Thu, 19 Jan 2023 19:27:32 GMT, Paul Ratcliffe

Post by Paul Ratcliffe
On Tue, 17 Jan 2023 21:22:32 +0000, Brian Gregory

Post by Brian Gregory
The error detection and correction on the protocols they use was
designed a long time ago and is very crude. This means there is a
relatively high chance of interference or weak signal causing the clock
to set itself incorrectly.

There is no error correction, only detection using parity.
8 bits are used for framing
4 bits are used for parity
53 bits are used for data
53 bits are unused (currently)
Any decent controller should at least wait for error-free consistent
data for at least 2 complete minutes before setting the clock.
That catches most of the errors that the parity checks don't.
That's what I did in my software anyway, way back when I wrote it
for the Maplin receiver module.

Does any of this explain how Mark's clock could be 2 hours fast at the
same time as mine was two hours slow, probably living about 500 miles
apart?

[Brian Gregory]

Post by Scott
Does any of this explain how Mark's clock could be 2 hours fast at the
same time as mine was two hours slow, probably living about 500 miles
apart?

I think we'd have heard about this elsewhere if this was anything other
than a co-incidence.

[Mark Carver]

Post by Brian Gregory

Post by Scott
Does any of this explain how Mark's clock could be 2 hours fast at the
same time as mine was two hours slow, probably living about 500 miles
apart?

I think we'd have heard about this elsewhere if this was anything
other than a co-incidence.

Indeed. My clock has been fine since too, so just a co incidence

[Scott]

On Fri, 20 Jan 2023 08:08:14 +0000, Mark Carver

Post by Mark Carver

Post by Brian Gregory

Post by Scott
Does any of this explain how Mark's clock could be 2 hours fast at the
same time as mine was two hours slow, probably living about 500 miles
apart?

I think we'd have heard about this elsewhere if this was anything
other than a co-incidence.

Indeed. My clock has been fine since too, so just a co incidence

And so has mine ...

I wish I had been able to go to Paddy Power on this one. I think I
would have been the richest man in Britain :-)

[Paul Ratcliffe]

Post by Scott
On Thu, 19 Jan 2023 19:27:32 GMT, Paul Ratcliffe

Post by Paul Ratcliffe
On Tue, 17 Jan 2023 21:22:32 +0000, Brian Gregory

Post by Brian Gregory
The error detection and correction on the protocols they use was
designed a long time ago and is very crude. This means there is a
relatively high chance of interference or weak signal causing the clock
to set itself incorrectly.

There is no error correction, only detection using parity.
8 bits are used for framing
4 bits are used for parity
53 bits are used for data
53 bits are unused (currently)
Any decent controller should at least wait for error-free consistent
data for at least 2 complete minutes before setting the clock.
That catches most of the errors that the parity checks don't.
That's what I did in my software anyway, way back when I wrote it
for the Maplin receiver module.

Does any of this explain how Mark's clock could be 2 hours fast at the
same time as mine was two hours slow, probably living about 500 miles
apart?

No.

[Liz Tuddenham]

Post by Scott
On Thu, 19 Jan 2023 19:27:32 GMT, Paul Ratcliffe

Post by Paul Ratcliffe
On Tue, 17 Jan 2023 21:22:32 +0000, Brian Gregory

Post by Brian Gregory
The error detection and correction on the protocols they use was
designed a long time ago and is very crude. This means there is a
relatively high chance of interference or weak signal causing the clock
to set itself incorrectly.

There is no error correction, only detection using parity.
8 bits are used for framing
4 bits are used for parity
53 bits are used for data
53 bits are unused (currently)
Any decent controller should at least wait for error-free consistent
data for at least 2 complete minutes before setting the clock.
That catches most of the errors that the parity checks don't.
That's what I did in my software anyway, way back when I wrote it
for the Maplin receiver module.

Does any of this explain how Mark's clock could be 2 hours fast at the
same time as mine was two hours slow, probably living about 500 miles
apart?

I've had one jump about two hours fast when the battery connection was
slightly corroded. When the alarm tried to go off, the extra load of
the dial light broke the tenuous battery connection and stopped the
clock. It then reconnected and the clock re-started from the position
the hands were in. This was just before the hour, so the hands did
almost a complete turn before coming back into synch.

At this point the alarm tried to go off again and the whole process
repeated itself, ending up with the clock approximately two hours fast.

I was woken by a feeble squeak from the second alarm attempt, looked at
the clock and found the hands whizzing around because it had just done a
restart.

[MB]

I know that any time I have any problems with one of the clocks I check
the battery or just change it. Most electronic items tend to behave
erratically when the batteries are low. Sometimes even though the
battery voltage seems normal, the fault will clear after a battery change.

[charles]

Post by MB
I know that any time I have any problems with one of the clocks I check
the battery or just change it. Most electronic items tend to behave
erratically when the batteries are low. Sometimes even though the
battery voltage seems normal, the fault will clear after a battery change.

nothing really changes, When I first started doing equipment maintenance in
the 1960s, the first thing to look at was the power supply.

[Scott]

On Fri, 20 Jan 2023 14:29:30 +0000 (GMT), charles

Post by charles

Post by MB
I know that any time I have any problems with one of the clocks I check
the battery or just change it. Most electronic items tend to behave
erratically when the batteries are low. Sometimes even though the
battery voltage seems normal, the fault will clear after a battery change.

nothing really changes, When I first started doing equipment maintenance in
the 1960s, the first thing to look at was the power supply.

With possessing any electrical knowledge, I understand that it the
battery goes flat the device usually stops working.

[MB]

Post by Scott
With possessing any electrical knowledge, I understand that it the
battery goes flat the device usually stops working.

But before the battery is 'flat' they can often do strange things.

[Scott]

On Fri, 20 Jan 2023 16:08:47 +0000, Scott

Post by Scott
On Fri, 20 Jan 2023 14:29:30 +0000 (GMT), charles

Post by charles

Post by MB
I know that any time I have any problems with one of the clocks I check
the battery or just change it. Most electronic items tend to behave
erratically when the batteries are low. Sometimes even though the
battery voltage seems normal, the fault will clear after a battery change.

nothing really changes, When I first started doing equipment maintenance in
the 1960s, the first thing to look at was the power supply.

With possessing any electrical knowledge, I understand that it the
battery goes flat the device usually stops working.

I mean 'Without possessing'

[Chris Youlden]

Post by Scott
On Fri, 20 Jan 2023 14:29:30 +0000 (GMT), charles

Post by charles

Post by MB
I know that any time I have any problems with one of the clocks I check
the battery or just change it. Most electronic items tend to behave
erratically when the batteries are low. Sometimes even though the
battery voltage seems normal, the fault will clear after a battery change.

nothing really changes, When I first started doing equipment maintenance in
the 1960s, the first thing to look at was the power supply.

With possessing any electrical knowledge, I understand that it the
battery goes flat the device usually stops working.

You'd make a great engineer. The other thing you need to know before you
qualify is - if it's not working, kick it.

[Scott]

Post by Chris Youlden

Post by Scott
On Fri, 20 Jan 2023 14:29:30 +0000 (GMT), charles

Post by charles

Post by MB
I know that any time I have any problems with one of the clocks I check
the battery or just change it. Most electronic items tend to behave
erratically when the batteries are low. Sometimes even though the
battery voltage seems normal, the fault will clear after a battery change.

nothing really changes, When I first started doing equipment maintenance in
the 1960s, the first thing to look at was the power supply.

With possessing any electrical knowledge, I understand that it the
battery goes flat the device usually stops working.

You'd make a great engineer. The other thing you need to know before you
qualify is - if it's not working, kick it.

I thought that was the role of HR :-)

[charles]

Post by Chris Youlden

Post by Scott
On Fri, 20 Jan 2023 14:29:30 +0000 (GMT), charles

Post by charles

Post by MB
I know that any time I have any problems with one of the clocks I
check the battery or just change it. Most electronic items tend to
behave erratically when the batteries are low. Sometimes even though
the battery voltage seems normal, the fault will clear after a
battery change.

nothing really changes, When I first started doing equipment
maintenance in the 1960s, the first thing to look at was the power
supply.

With possessing any electrical knowledge, I understand that it the
battery goes flat the device usually stops working.

You'd make a great engineer. The other thing you need to know before you
qualify is - if it's not working, kick it.

That is known, technically, as "Percussive Maintenance"

[MB]

Post by charles
That is known, technically, as "Percussive Maintenance"

Using a Manchester Screwdriver.

[NY]

Post by Paul Ratcliffe
Any decent controller should at least wait for error-free consistent
data for at least 2 complete minutes before setting the clock.
That catches most of the errors that the parity checks don't.
That's what I did in my software anyway, way back when I wrote it
for the Maplin receiver module.

How often is the time data sent? 2 minutes seems a long time to wait, but I
suppose if the time updates are 1 minute apart (for example), 2 minutes is
only two samples to check for consistency.


The very old clock/radio (*) that my wife had before I met her had
particularly stupid radio-controlled clock. It had a habit of adjusting
itself to random time, usually doing this in the middle of the night when
no-one was awake to notice that the clock was wrong. This meant that the
alarm didn't go off at the time it was set (because it was set for 07:00 but
the clock time was wrong), so it either went off in the middle of the night
or else long after she should have set off for work. And it had no way of
manually setting the time, so even if you noticed the night before, you
couldn't put it right (and hope it didn't get auto-adjusted to the wrong
time after that) - you had to want many hours until the time corrected
itself.

That radio went in the bin (after I'd had a quick look inside in case there
was obvious sign of the radio-clock aerial being detached). No we use Alexas
as (amongst other things) alarm clocks.

Are radio-controlled "Rugby/Anthorn" clocks still used much these days? I
imagine that as long as you have wifi link to an internet connection, you
can use an NTP source to get an update within a fraction of a second. Are
there any simple clocks which do this - apart from multi-purpose devices
like Alexa which do so much more as well.


(*) It was old enough that it had manual radio tuning with a rotary knob, a
needle that moved across a scale and a variable capacitor, rather than
digital synthesised tuning indicated on the LED display. Probably about 30
years old.

[Woody]

Post by NY

Post by Paul Ratcliffe
Any decent controller should at least wait for error-free consistent
data for at least 2 complete minutes before setting the clock.
That catches most of the errors that the parity checks don't.
That's what I did in my software anyway, way back when I wrote it
for the Maplin receiver module.

How often is the time data sent? 2 minutes seems a long time to wait,
but I suppose if the time updates are 1 minute apart (for example), 2
minutes is only two samples to check for consistency.
The very old clock/radio (*) that my wife had before I met her had
particularly stupid radio-controlled clock. It had a habit of adjusting
itself to random time, usually doing this in the middle of the night
when no-one was awake to notice that the clock was wrong. This meant
that the alarm didn't go off at the time it was set (because it was set
for 07:00 but the clock time was wrong), so it either went off in the
middle of the night or else long after she should have set off for work.
And it had no way of manually setting the time, so even if you noticed
the night before, you couldn't put it right (and hope it didn't get
auto-adjusted to the wrong time after that) - you had to want many hours
until the time corrected itself.
That radio went in the bin (after I'd had a quick look inside in case
there was obvious sign of the radio-clock aerial being detached). No we
use Alexas as (amongst other things) alarm clocks.
Are radio-controlled "Rugby/Anthorn" clocks still used much these days?
I imagine that as long as you have wifi link to an internet connection,
you can use an NTP source to get an update within a fraction of a
second. Are there any simple clocks which do this - apart from
multi-purpose devices like Alexa which do so much more as well.
(*) It was old enough that it had manual radio tuning with a rotary
knob, a needle that moved across a scale and a variable capacitor,
rather than digital synthesised tuning indicated on the LED display.
Probably about 30 years old.

The off-air clocks are still widely use - indeed we fitted a new CH
timeswitch a few years ago and that uses MSF.
Having said that most such clocks come from Aldi or Lidl and I have
found that they mostly use DCF but have an offset capability so that
they can be used in any country in which they are sold.

[Paul Ratcliffe]

Post by NY

Post by Paul Ratcliffe
Any decent controller should at least wait for error-free consistent
data for at least 2 complete minutes before setting the clock.
That catches most of the errors that the parity checks don't.
That's what I did in my software anyway, way back when I wrote it
for the Maplin receiver module.

How often is the time data sent? 2 minutes seems a long time to wait, but I
suppose if the time updates are 1 minute apart (for example), 2 minutes is
only two samples to check for consistency.

Every minute, which is why I said it takes at least two minutes - to receive
two complete frames.

[joe bloggs]

Curiously I have noticed that our RC clock is exactly one hour slow and has been like this for a few days. I have tried a power off/on etc but no difference.

The icon on the front panel display indicates it is receiving an RF signal. (Oregon RF308PU) . We have noted that in all the years we have owned it when there is a change to and from GMT/BST etc the clock display is incorrect for a week or so after the change and then corrects itself with no intervention. Odd.