Radio controlled clock

[Scott]

My radio controlled clock (Lexon Flip+) gained 10 minutes. My first
thought was that the battery might be flat and the clock stopped then
restarted. However, it is a very new battery. My second thought was
that the time signal (from Frankfurt) might have been affected by
atmospheric conditions. However, this has never happened before and I
cannot see how this could cause the clock to gain time. My third
thought was a fault at the transmitter. However, I restarted the clock
(removing the battery) and it picked up the time very quickly. I
cannot see how a main transmitter for Europe could be faulty.

I understood if the radio signal is lost, the clock has the ability to
keep time internally (the radio control can be switched off). I am
therefore mystified how this clock could gain 10 minutes. Any ideas?

[J. P. Gilliver]

In message <i58sei1im50lm8701...@4ax.com> at Tue, 29 Aug
2023 17:54:54, Scott <newsg...@gefion.myzen.co.uk> writes

Just one bad decode? (Maybe the 'fridge kicked in at the precise moment
the update code was received?) Though that _ought_ of course to have
corrected itself next update (do you know how often - once a minute?). I
suppose the combined system - radio decoder and free-running backup -
_could_ just get into some condition where it remains ten minutes out.

I continue to be amazed that my cheap one from Lidl runs for many years
on a single AA cell (and yes, it really is receiving). [I thought it
needed two cells, then I worked out that one was only needed for the
pressbutton backlight!]
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

"... all your hard work in the hands of twelve people too stupid to get off
jury
duty." CSI, 200x

[JMB99]

On 29/08/2023 17:54, Scott wrote:
> I understood if the radio signal is lost, the clock has the ability to
> keep time internally (the radio control can be switched off). I am
> therefore mystified how this clock could gain 10 minutes. Any ideas?

People often think that the clocks are synchronised to a Standard
Frequency Station all the time but most only update periodically. It
might be several times a day or only once a day.

Many indicate how long since the last update.

[Woody]

Most clocks synchronise at 04h00 to make sure they don't crash with DST
start/stop.

[Brian Gregory]

On 29/08/2023 17:54, Scott wrote:

A 1 bit error in decoding the binary coded decimal time could throw the
time off by 1, 2, 4, 8, 10, 20 or 40 minutes or 1, 2, 4, 8, 10 or 20 hours.

The error checking is probably only a very crude parity or checksum
and/or it reads the signal twice and checks for consistency so it's
unlikely but definitely possible for this to happen.

Once that has happened the clock stays wrong until next time it turns on
its receiver typically in the small hours around 24 hours later.

--
Brian Gregory (in England).

[Brian Gregory]

On 29/08/2023 19:00, Woody wrote:
> Most clocks synchronise at 04h00 to make sure they don't crash with DST
> start/stop.

I've never owned one that didn't sync at 0100 standard time or 0200
daylight saving time, That is immediately after any time change.

[Scott]

Thanks for this. It seems more likely than the clock gaining 10
minutes between signal checks.

[J. P. Gilliver]

In message <uclb9p$2bpib$1...@dont-email.me> at Tue, 29 Aug 2023 18:52:56,
JMB99 <m...@nospam.net> writes

Many - LCD ones, anyway, not sure about mechanical ones - have a symbol
to show whether they're receiving the radio signal. I get the impression
that they don't go _that_ long without a correction (again, mechanical
ones may be less often for battery reasons).

--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

I don't see the requirement to upset people. ... There's enough to make fun of
without offending. - Ronnie Corbett, in Radio Times 6-12 August 2011.

[JMB99]

On 30/08/2023 02:08, J. P. Gilliver wrote:
> Many - LCD ones, anyway, not sure about mechanical ones - have a symbol
> to show whether they're receiving the radio signal. I get the impression
> that they don't go _that_ long without a correction (again, mechanical
> ones may be less often for battery reasons).

My first Junghans displayed how many hours since the last update, I
think if it fails to update first time then it keeps retrying at
intervals so can be seen to update during the day.

My second Junghans is a proper folding travel clock but it has died.
pity because I liked that one.

I have a Braun one as well, I once went away for the week and forget to
take an alarm clock so bought the Braun. Never liked it as much as the
Junghans but it can be switched between about four different Standard
Frequency Stations (not I have ever used the US or Japanese ones!). The
alarm has stopped working.

I keep the original Junghans on my desk because it displays seconds so
useful for setting the time on my wrist watch.

I was just trying to find the second Junghans and came across the alarm
clock that Crown Castle gave everyone one year, I had never taken it out
of the box. Brilliant design, you are supposed to take to a
'professional engineer' to get the battery changed so probably all
corroded now. The instruction tells you how to set the time but there
does not seem any way to do so because it does not have the adjuster on
the side! Perhaps symbolic of Crown Castle.

[MikeS]

I have 3 radio wall clocks plus one in a weather station and am
convinced this is an interference problem with cheap clocks.

The oldest wall and the weather station were made in Germany, probably
use their PTB time signal, and have never had a problem. The other 2
wall are cheap ones from Argos and both have irregular gliches, either
going crazy or showing wrong time. They might use the same signal but
more likely the closer NPL one. Not a battery issue - I wasted money on
batteries until I realised that a quick reset would usually suffice.

At this moment all 4 have been perfect for weeks, showing identical
times to the second.

[Scott]

Do you think atmospherics have a part to play?

[Woody]

The biggest problem is range.

DCF near Frankfurt on 77.5khz is supposed to have a range of 1500km
during the day but IME it is not as good as that - maybe 1000km most
days - but it does work fairly reliably here in Harrogate.

When MSF on 60khz was at Rugby it would work solidly 24/7, but since it
was moved to Anthorn, about 7m NNW of Wigton in NW Cumbria, it is
rubbish. If I check any of my clocks (daftly against my PC which uses
NPL) and the clock is in error I have no option but to restart it and
place it on a bedroom windowsill at the back of the house (which faces
NNE), put it anywhere else in the house and it might (downhill with a
following wind) get the time anything up to 48hrs or more later.

I used to have a cheap off-air watch and that was solid as a rock.

[JMB99]

On 31/08/2023 14:45, Woody wrote:
> DCF near Frankfurt on 77.5khz is supposed to have a range of 1500km
> during the day but IME it is not as good as that - maybe 1000km most
> days - but it does work fairly reliably here in Harrogate.

Never had any serious problems with DCF77, it has the big advantage that
it never goes off. They have standby site which is used during
maintenance periods (you can even correct for the different location if
using professional equipment).

MSF is taken off for maintenance regularly (can't remember how and when
but they publish times). My first MSF clock had the usual big bar
across the top of the clock to cancel the alarm. This also switched the
light on so had to be careful that not switched on in the suitcase in
case battery ran down. So I sometimes took the battery out in transit
because the time would set itself quickly, unless MSF was off and the
clock had no method of manually setting the time!

My other PC is used by Planeplotter and has to have accurate time so I
have Meinburg NTP running.

[Scott]

On Thu, 31 Aug 2023 14:45:13 +0100, Woody <harro...@ntlworld.com>
wrote:
[snip]

>>
>> Do you think atmospherics have a part to play?
>
>The biggest problem is range.
>
>DCF near Frankfurt on 77.5khz is supposed to have a range of 1500km
>during the day but IME it is not as good as that - maybe 1000km most
>days - but it does work fairly reliably here in Harrogate.

I had an early radio controlled clock (MSF) when I was in Fife. It
wouldn't work at first but after leaving it overnight on the window
ledge, it worked. I assume propagation improves at night and night
time interference is unimportant?

>
>When MSF on 60khz was at Rugby it would work solidly 24/7, but since it
>was moved to Anthorn, about 7m NNW of Wigton in NW Cumbria, it is
>rubbish. If I check any of my clocks (daftly against my PC which uses
>NPL) and the clock is in error I have no option but to restart it and
>place it on a bedroom windowsill at the back of the house (which faces
>NNE), put it anywhere else in the house and it might (downhill with a
>following wind) get the time anything up to 48hrs or more later.

Being in Scotland, I think this represents an improvement as we are a
lot closer to Cumbria (which I believe has been abolished). It always
amused me when the A74 had a sign going north saying 'Welcome to
Scotland' but going south it was 'Welcome to Cumbria'.

[Roderick Stewart]

On Thu, 31 Aug 2023 14:45:13 +0100, Woody <harro...@ntlworld.com>
wrote:

>When MSF on 60khz was at Rugby it would work solidly 24/7, but since it
>was moved to Anthorn, about 7m NNW of Wigton in NW Cumbria, it is
>rubbish.

It's always been fine in Liverpool.

Rod.

[Woody]

I have two of those type clocks - had 'em for maybe 20 years - one sits
in our conservatory and the other in my shed. IMSMC they take 2AA's and
such batteries easily last two years and they are never wrong.

I feed FlightRadar24 but NPL as the reference seems to work quite well
for Windows 10 Pro. Given FR24 know <exactly> where I am located and
which are my local active airfields I doubt they would have any problems
adjusting my time data!

[Woody]

I suppose it could be local RFI which is why they work better on a
windowsill or outside the house walls. I did a quick count about six
months ago, we have something like 38 SMPS wall-warts permanently
active. I wonder how much carp (like that?) they are throwing out?

[JMB99]

On 31/08/2023 16:17, Woody wrote:
> I feed FlightRadar24 but NPL as the reference seems to work quite well
> for Windows 10 Pro. Given FR24 know <exactly> where I am located and
> which are my local active airfields I doubt they would have any problems
> adjusting my time data!

I don't think FR24 accepts feeds from PCs so I don't feed it but I never
use the site, much prefer ADS-B.

[Woody]

If they don't accept them I wonder what I have been doing for the last
2+ years?

I have a receiver in the loft receiving ADS-B, pushes it into a RPi 3B
which sends it to FR24. What is it that you do that is different?

[JMB99]

On 31/08/2023 17:53, Woody wrote:
>
> If they don't accept them I wonder what I have been doing for the last
> 2+ years?
>
> I have a receiver in the loft receiving ADS-B, pushes it into a RPi 3B
> which sends it to FR24. What is it that you do that is different?

This is what FR24 has on its website

"Flightradar24 data sharing software is available for:
Raspberry Pi
Linux"

No mention of anything else.

Normally tracking sites do not allow data to be forwarded to another
site. I had an argument years ago with a site that was taking my data
off ShipPlotter and using it.

[Paul Ratcliffe]

On Thu, 31 Aug 2023 17:53:33 +0100, Woody <harro...@ntlworld.com> wrote:

>> I don't think FR24 accepts feeds from PCs so I don't feed it but I never
>> use the site, much prefer ADS-B.
>
> If they don't accept them I wonder what I have been doing for the last
> 2+ years?
>
> I have a receiver in the loft receiving ADS-B, pushes it into a RPi 3B
> which sends it to FR24.

A Raspberry Pi is not a PC though is it? Read what was written.

You *can* use a PC, as long as it is running Linux.
I know, stupid people think PCs only run Windows, but they really don't.

I run my RX on a Pi 2B.

[JMB99]

On 31/08/2023 19:10, Paul Ratcliffe wrote:
> You *can* use a PC, as long as it is running Linux. I know, stupid
> people think PCs only run Windows, but they really don't.

True but my PC is running Windows and not going to change it just
because FR24 no longer support Windows.

[Brian Gregory]

On 31/08/2023 13:28, Scott wrote:
> Do you think atmospherics have a part to play?

More likely Day/Night and "space weather" - sunspot numbers etc.

The signals seem better late at night but maybe it's due to lack of
local interference. I've never attempted to monitor and compare the
signal strength with an SDR.

[Brian Gaff]

Well, it probably depends on how its built. early ones were simple decoders
based on hardware and logic chips, but more and more are in fact using
software running on a processor and its entirely possible for software to
get corrupted and a reboot restores the original if some of the system
relies on ram storage of things that were the corrupted bits.
Brian

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