Can a quartz crystal go off by 2% ?
Over here they use a tone system that is modulated onto the mains to
operate a relay to switch over to night rate and turn on the immersion
heater in the hot water cylinder.
Steve Rooke
2009/12/29 Rob Kimberley rk@timing-consultants.com:
AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said, I
would have thought once synchronised, they would "tick" off the 50 Hz
supply.
Rob Kimberley
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Dr. David Kirkby
Sent: 28 December 2009 23:22
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Can a quartz crystal go off by 2% ?
I'm on the so-called 'Economy 7' electric in the UK, where I'm supposed to
get
cheap electric from 0030 to 0730 - i.e. a 7 hour period when electricity
demand
is low. I'm no longer heating by electric, but do run some computers 24/7.
It's
not totally clear whether this saves me money or costs me money, as I pay a
higher price per unit during the expensive period, to compensate for the
fact I
get it cheap for 7 hours. But I run some computers 24/7. I guess I should do
the
maths and work it out. Apart from some heaters in the garage, which are very
rarely used, I no longer heat with it.
The time when the electric is cheap is set by a clock, which rotates
once/day.
It says on it "quartz" somewhere, so it must be regulated by a crystal and
not
from the 50 Hz supply, which would be pretty useless, as the clock would go
wrong if there was ever a power failure. The clock has not been changed in
the
17 years I've lived at my house, though the meter has on a couple of
occasions.
The clock used to keep accurate, but now it looses time about 30
minutes/day. I
wrote a computer program to predict when the electric is cheap, so we can
schedule when things like the washing machine, dishwasher, Hoover etc are
used.
Even cooking to a certain extent, if it's convenient, though our life does
not
revolve around the cheap electric.
I'm wondering if this is a mechanical fault in the clock, or whether the
crystal
has developed a fault. It's clearly well outside any tolerance or aging
process
of any crystal - even the cheapest ones.
I've not done any very extensive tests, but the error does not appear to be
constant. Hence every month or so I need to produce a new table, as my
predictions get less accurate with time. Since one can only read the clock
to an
accuracy of about 15 minutes, it's not easy to know how far it is out.
Sometimes
we hear the contactor go over, as this is supposed to then power the storage
heaters, which we no long use.
Dave
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--
Steve Rooke - ZL3TUV & G8KVD
A man with one clock knows what time it is;
A man with two clocks is never quite sure.
Rob Kimberley wrote:
AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said, I
would have thought once synchronised, they would "tick" off the 50 Hz
supply.
Rob Kimberley
The electricity bill always states the times are approximately 0030 to 0730 GMT.
Therefore, there is no change for daylight saving.
Dave
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Dr. David Kirkby
Sent: 28 December 2009 23:22
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Can a quartz crystal go off by 2% ?
I'm on the so-called 'Economy 7' electric in the UK, where I'm supposed to
get
cheap electric from 0030 to 0730 - i.e. a 7 hour period when electricity
demand
is low. I'm no longer heating by electric, but do run some computers 24/7.
It's
not totally clear whether this saves me money or costs me money, as I pay a
higher price per unit during the expensive period, to compensate for the
fact I
get it cheap for 7 hours. But I run some computers 24/7. I guess I should do
the
maths and work it out. Apart from some heaters in the garage, which are very
rarely used, I no longer heat with it.
The time when the electric is cheap is set by a clock, which rotates
once/day.
It says on it "quartz" somewhere, so it must be regulated by a crystal and
not
from the 50 Hz supply, which would be pretty useless, as the clock would go
wrong if there was ever a power failure. The clock has not been changed in
the
17 years I've lived at my house, though the meter has on a couple of
occasions.
The clock used to keep accurate, but now it looses time about 30
minutes/day. I
wrote a computer program to predict when the electric is cheap, so we can
schedule when things like the washing machine, dishwasher, Hoover etc are
used.
Even cooking to a certain extent, if it's convenient, though our life does
not
revolve around the cheap electric.
I'm wondering if this is a mechanical fault in the clock, or whether the
crystal
has developed a fault. It's clearly well outside any tolerance or aging
process
of any crystal - even the cheapest ones.
I've not done any very extensive tests, but the error does not appear to be
constant. Hence every month or so I need to produce a new table, as my
predictions get less accurate with time. Since one can only read the clock
to an
accuracy of about 15 minutes, it's not easy to know how far it is out.
Sometimes
we hear the contactor go over, as this is supposed to then power the storage
heaters, which we no long use.
Dave
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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and follow the instructions there.
Do you have a photo of your meter?
Rob
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Dr. David Kirkby
Sent: 29 December 2009 13:59
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Can a quartz crystal go off by 2% ?
Rob Kimberley wrote:
AFIK a lot of the clocks were radio controlled from MSF Rugby (now
Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said,
I
would have thought once synchronised, they would "tick" off the 50 Hz
supply.
Rob Kimberley
The electricity bill always states the times are approximately 0030 to 0730
GMT.
Therefore, there is no change for daylight saving.
Dave
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Dr. David Kirkby
Sent: 28 December 2009 23:22
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Can a quartz crystal go off by 2% ?
I'm on the so-called 'Economy 7' electric in the UK, where I'm supposed to
get
cheap electric from 0030 to 0730 - i.e. a 7 hour period when electricity
demand
is low. I'm no longer heating by electric, but do run some computers 24/7.
It's
not totally clear whether this saves me money or costs me money, as I pay
a
higher price per unit during the expensive period, to compensate for the
fact I
get it cheap for 7 hours. But I run some computers 24/7. I guess I should
do
the
maths and work it out. Apart from some heaters in the garage, which are
very
rarely used, I no longer heat with it.
The time when the electric is cheap is set by a clock, which rotates
once/day.
It says on it "quartz" somewhere, so it must be regulated by a crystal and
not
from the 50 Hz supply, which would be pretty useless, as the clock would
go
wrong if there was ever a power failure. The clock has not been changed in
the
17 years I've lived at my house, though the meter has on a couple of
occasions.
The clock used to keep accurate, but now it looses time about 30
minutes/day. I
wrote a computer program to predict when the electric is cheap, so we can
schedule when things like the washing machine, dishwasher, Hoover etc are
used.
Even cooking to a certain extent, if it's convenient, though our life does
not
revolve around the cheap electric.
I'm wondering if this is a mechanical fault in the clock, or whether the
crystal
has developed a fault. It's clearly well outside any tolerance or aging
process
of any crystal - even the cheapest ones.
I've not done any very extensive tests, but the error does not appear to
be
constant. Hence every month or so I need to produce a new table, as my
predictions get less accurate with time. Since one can only read the clock
to an
accuracy of about 15 minutes, it's not easy to know how far it is out.
Sometimes
we hear the contactor go over, as this is supposed to then power the
storage
heaters, which we no long use.
Dave
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
and follow the instructions there.
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To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
I wonder how the power company changes the meter rate, based on the local
timer. Are there two different meters, with a separate circuit for cheap
loads?
Perhaps not, because you continue to run your computers without
interruption. OTOH, you said in the first posting, "Sometimes we hear the
contactor go over, as this is supposed to then power the storage heaters,
which we no long use."
If you don't power anything with the storage heater circuit, are you really
getting any "cheap" electric? Do your power bills show a difference as the
faulty clock loses time? Does the bill just show total power, or is there a
separate line item for cheap power?
Could the power company be ignoring clock maintenance because they know
that you no longer have storage heaters? Can the person reading the meter
see the time on the clock, or is reading automated?
Just another way of looking at the problem . . .
Bill Hawkins
-----Original Message-----
From: Dr. David Kirkby
Sent: Monday, December 28, 2009 7:19 PM
No, I'm quite happy to get cheap electric during the day some times! It's
more
useful than having it in the middle of the night. So I'm not concerned over
this, but just interested what might be the problem with it.
Hi Rob,
Actually they are controlled from a low bit-rate signal
phase-modulated onto Radio-4 long-wave (198KHz). If you have an SSB
or CW receiver that tunes down to that frequency, switch on the BFO
and look at the output on something like Spectrum Lab, and the phase
modulation is readily seen!
TTFN, Peter
2009/12/29 Rob Kimberley rk@timing-consultants.com:
AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said, I
would have thought once synchronised, they would "tick" off the 50 Hz
supply.
Rob Kimberley
They just switch the meter over to count "night" units. Strictly of course
both day and night units are counted as kWh, and the supply company apply
different charge rates to the "night units". Effectively there are two
meters in the same case that are switched over by the time clock output
signal.
There may also be a contactor connected to the line from the time clock to
the meter. That will switch on some circuits that are intended to be "night
only".
The guy who reads the meter just reads off "day units" and "night units",
and unless they suspect there's a problem with it they won't look at the
time clock.
D.
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Bill Hawkins
Sent: 29 December 2009 17:17
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Can a quartz crystal go off by 2% ?
I wonder how the power company changes the meter rate, based on the local
timer. Are there two different meters, with a separate circuit for cheap
loads?
Perhaps not, because you continue to run your computers without
interruption. OTOH, you said in the first posting, "Sometimes we hear the
contactor go over, as this is supposed to then power the storage heaters,
which we no long use."
If you don't power anything with the storage heater circuit, are you really
getting any "cheap" electric? Do your power bills show a difference as the
faulty clock loses time? Does the bill just show total power, or is there a
separate line item for cheap power?
Could the power company be ignoring clock maintenance because they know that
you no longer have storage heaters? Can the person reading the meter see the
time on the clock, or is reading automated?
Just another way of looking at the problem . . .
Bill Hawkins
Rob Kimberley wrote:
AFIK a lot of the clocks were radio controlled from MSF Rugby (now Anthorn,
Cumbria). You would need to have some sort of automated system to
accommodate daylight savings switchovers in Spring and Autumn. That said, I
would have thought once synchronised, they would "tick" off the 50 Hz
supply.
Radio 4, actually.
There's a low-speed phase-modulated signal riding on the 198kHz carrier,
which encodes the clock time and a few bits of data for "radio
teleswitching", i.e. Economy 7.
If you meddle about a bit with a PLL, you can even use it as a frequency
reference (it's apparently driven off a rubidium oscillator and the NPL
monitor its frequency in relation to the UK "standard" frequency, same
as they do with GPS and the Rugby/Anthorn/MSF time signal).
The fact that the meter isn't resetting itself implies that there's more
wrong with it than just the crystal. I'd go with a failure in the RF
section that's caused it to lose the teleswitching signal and
date/time... There's no RF (as far as it's concerned), thus it's fallen
back to the quartz in the dim hope that maybe, just maybe, it'll start
hearing the distant voice of R4 in the not too distant future...
It's another possibility, anyway.