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MSF radio clocks.



 
 
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  #61  
Old October 31st 17, 08:41 PM posted to uk.tech.digital-tv
Max Demian
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Posts: 3,897
Default MSF radio clocks.

On 31/10/2017 16:00, R. Mark Clayton wrote:
On Tuesday, 31 October 2017 15:38:32 UTC, Max Demian wrote:
On 31/10/2017 12:41, NY wrote:

I would imagine that the clock in a PC is normal crystal-controlled
accuracy - to within a couple of seconds per day. That's good enough for
most purposes, but every so often (every week IIRC) it synchronises with
a more accurate time reference to correct any drift. There's probably a
registry key to change the time between synchronisation attempts.


Looxury. I remember when you had to set the time on your PC every time
you booted it up, or all new files would be dated 1-1-1980.


Or you could buy a new battery for the motherboard.


I'm talking about the original PCs that didn't have a "real time" clock.

--
Max Demian
  #62  
Old October 31st 17, 09:08 PM posted to uk.tech.digital-tv
NY
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Posts: 1,237
Default MSF radio clocks.

"Max Demian" wrote in message
...
On 31/10/2017 16:00, R. Mark Clayton wrote:
On Tuesday, 31 October 2017 15:38:32 UTC, Max Demian wrote:
On 31/10/2017 12:41, NY wrote:

I would imagine that the clock in a PC is normal crystal-controlled
accuracy - to within a couple of seconds per day. That's good enough
for
most purposes, but every so often (every week IIRC) it synchronises
with
a more accurate time reference to correct any drift. There's probably a
registry key to change the time between synchronisation attempts.

Looxury. I remember when you had to set the time on your PC every time
you booted it up, or all new files would be dated 1-1-1980.


Or you could buy a new battery for the motherboard.


I'm talking about the original PCs that didn't have a "real time" clock.


Ah, the first IBM-compatible PC that I had was an ICL Model 30 (8086-based)
which may have had a BIOS chip that had an RTC which the original true-IBM
ones didn't.

Odd that IBM missed it out of their initial spec, given that other older
micros (like my Z80-based CP/M computer) did have an RTC.

I'm trying to remember whether my Dad's Amstrad PC had an RTC. I don't
remember him having to set the time and date every time he booted up.

  #63  
Old October 31st 17, 09:42 PM posted to uk.tech.digital-tv
Vir Campestris
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Posts: 416
Default Weird timepieces was MSF radio clocks.

On 31/10/2017 09:37, Indy Jess John wrote:
On 31/10/2017 09:20, Brian Gaff wrote:
There have been some odd clocks and watches made. I assume you all
remember
the ball bearing clock? did they ever work properly. Struck me they
were the
ultimate in tactile time telling.


I have got a ball bearing clock, though I don't use it any more.* It did
keep reasonable time but you had to put it level in both directions, and
even then sometimes the ball return on the hour didn't quite work,
leaving them caught at the end of the seesaw, and then the clock ran out
of balls to deliver and the whole thing stopped (except the motor) so it
had to be manually reset to the right time.

It was more of a conversation piece than a reliable clock.

I now wonder which clock you mean. I thought you meant
https://en.wikipedia.org/wiki/Congreve_clock
but there's no way you could read that by touch.

Andy

  #64  
Old October 31st 17, 10:36 PM posted to uk.tech.digital-tv
Indy Jess John
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Posts: 1,262
Default Weird timepieces was MSF radio clocks.

On 31/10/2017 21:42, Vir Campestris wrote:
On 31/10/2017 09:37, Indy Jess John wrote:
On 31/10/2017 09:20, Brian Gaff wrote:


It was more of a conversation piece than a reliable clock.

I now wonder which clock you mean. I thought you meant
https://en.wikipedia.org/wiki/Congreve_clock
but there's no way you could read that by touch.

Andy

This is my clock
http://www.dansdata.com/images/timemachine/lidon640.jpg

Jim

  #65  
Old October 31st 17, 11:13 PM posted to uk.tech.digital-tv
Max Demian
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Posts: 3,897
Default Weird timepieces was MSF radio clocks.

On 31/10/2017 22:36, Indy Jess John wrote:
On 31/10/2017 21:42, Vir Campestris wrote:
On 31/10/2017 09:37, Indy Jess John wrote:
On 31/10/2017 09:20, Brian Gaff wrote:


It was more of a conversation piece than a reliable clock.

I now wonder which clock you mean. I thought you meant
https://en.wikipedia.org/wiki/Congreve_clock
but there's no way you could read that by touch.


This is my clock
http://www.dansdata.com/images/timemachine/lidon640.jpg


So were the balls purely for indication purposes, with the timekeeping
determined by a synchronous motor?

--
Max Demian
  #66  
Old November 1st 17, 03:11 AM posted to uk.tech.digital-tv
Johnny B Good[_2_]
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Posts: 469
Default MSF radio clocks.

On Tue, 31 Oct 2017 21:08:44 +0000, NY wrote:

"Max Demian" wrote in message
...
On 31/10/2017 16:00, R. Mark Clayton wrote:
On Tuesday, 31 October 2017 15:38:32 UTC, Max Demian wrote:
On 31/10/2017 12:41, NY wrote:

I would imagine that the clock in a PC is normal crystal-controlled
accuracy - to within a couple of seconds per day. That's good enough
for most purposes, but every so often (every week IIRC) it
synchronises with a more accurate time reference to correct any
drift. There's probably a registry key to change the time between
synchronisation attempts.

Looxury. I remember when you had to set the time on your PC every
time you booted it up, or all new files would be dated 1-1-1980.


Or you could buy a new battery for the motherboard.


I'm talking about the original PCs that didn't have a "real time"
clock.


Ah, the first IBM-compatible PC that I had was an ICL Model 30
(8086-based)
which may have had a BIOS chip that had an RTC which the original
true-IBM ones didn't.


The BIOS roms were either mask programmed or else an EPROM (Flashable
NVRAM, EEPROMs, came many years later). The most probable reason for the
existence of an RTC chip would be because one of the 8bit adapters
included one (typically multi i/o adapters and serial parallel port
cards). At one point, I was rather spoilt for choice since three of the
adapters that I'd fitted to my home built (from 2nd hand parts) PC or XT
were equipped with RTCs, Dallas chips most likely but my memories of the
details after some three decades are rather hazy.


Odd that IBM missed it out of their initial spec, given that other older
micros (like my Z80-based CP/M computer) did have an RTC.

I'm trying to remember whether my Dad's Amstrad PC had an RTC. I don't
remember him having to set the time and date every time he booted up.


Possibly the RTC was courtesy of an adapter card or else he suppressed
the request for date and time by making an autoexec.bat file, the
presence of which would stop MSDOS midering the user with this question.
The logic behind this being that when you used an autoexec.bat file, you
could explicitly include the date and time request if needed due to a
lack of an RTC or else leave the questions out if an io card with an RTC
was installed. These RTC blessed adapters were normally supplied with
their own setup program which included either a TSR run from the
autoexec.bat file or else a driver launched from the config.sys file
(possibly both files needed RTC entries - it was a long time ago!).

--
Johnny B Good
  #67  
Old November 1st 17, 07:49 AM posted to uk.tech.digital-tv
Indy Jess John
external usenet poster
 
Posts: 1,262
Default Weird timepieces was MSF radio clocks.

On 31/10/2017 23:13, Max Demian wrote:
On 31/10/2017 22:36, Indy Jess John wrote:
On 31/10/2017 21:42, Vir Campestris wrote:
On 31/10/2017 09:37, Indy Jess John wrote:
On 31/10/2017 09:20, Brian Gaff wrote:


It was more of a conversation piece than a reliable clock.

I now wonder which clock you mean. I thought you meant
https://en.wikipedia.org/wiki/Congreve_clock
but there's no way you could read that by touch.


This is my clock
http://www.dansdata.com/images/timemachine/lidon640.jpg


So were the balls purely for indication purposes, with the timekeeping
determined by a synchronous motor?

There was a motor driving a scoop that picked up a ball from a ball pool
every minute and deposited it on the 5-minute tray. The fifth ball made
it heavy enough to tilt a seesaw that passed one ball to the 60-minute
tray and passed the remainder into the ball pool. The twelfth ball in
the 60-minute tray tipped that seesaw with one ball going into the Hours
tray and the rest returned to the ball pool. The Hours tray had one
captive ball (so that the minimum it showed was one hour) and the 13th
ball tipped the seesaw changing the hours from 12 to 1, and the whole
cycle started again.

It was interesting to watch but it took a little bit of arithmetic to
work out the time.

Jim

  #68  
Old November 1st 17, 11:45 AM posted to uk.tech.digital-tv
David Woolley[_2_]
external usenet poster
 
Posts: 544
Default MSF radio clocks.

On 31/10/17 19:31, Phil M wrote:
My pc with Win10 is, as far as I know, always correct and changed
automatically this Sunday. Just checked and is perfectly in sync with
my rds radio.


An un-customised Windows client is likely to be correct within around a
second. A customised one should be able to achieve better than 20ms
repeatability. A well tuned Linux system should be able to achieve
repeatability in the microseconds range.

Both Linux and Windows, in modern versions, will use the NTP wire
formats and NTP servers, but Windows clients are optimised for extremely
low network loadings, and only enough accuracy for their Kerberos based
authentication to work well. Windows server products are defaulted to
keep rather better time than clients.

Daylight saving time changes are not part of the time synchronisation;
the over the wire protocol is purely in UTC. There are files that
describe when changes happen in the various timezones. Linux has always
used UTC internally; modern Windows also uses UTC internally, but uses
wall clock time in the battery backed clock, for historical reasons
(MSDOS had no knowledge of time zones.)
  #69  
Old November 1st 17, 12:21 PM posted to uk.tech.digital-tv
Davey
external usenet poster
 
Posts: 2,283
Default Weird timepieces was MSF radio clocks.

On Wed, 01 Nov 2017 07:49:02 +0000
Indy Jess John wrote:

On 31/10/2017 23:13, Max Demian wrote:
On 31/10/2017 22:36, Indy Jess John wrote:
On 31/10/2017 21:42, Vir Campestris wrote:
On 31/10/2017 09:37, Indy Jess John wrote:
On 31/10/2017 09:20, Brian Gaff wrote:

It was more of a conversation piece than a reliable clock.

I now wonder which clock you mean. I thought you meant
https://en.wikipedia.org/wiki/Congreve_clock
but there's no way you could read that by touch.


This is my clock
http://www.dansdata.com/images/timemachine/lidon640.jpg


So were the balls purely for indication purposes, with the
timekeeping determined by a synchronous motor?

There was a motor driving a scoop that picked up a ball from a ball
pool every minute and deposited it on the 5-minute tray. The fifth
ball made it heavy enough to tilt a seesaw that passed one ball to
the 60-minute tray and passed the remainder into the ball pool. The
twelfth ball in the 60-minute tray tipped that seesaw with one ball
going into the Hours tray and the rest returned to the ball pool.
The Hours tray had one captive ball (so that the minimum it showed
was one hour) and the 13th ball tipped the seesaw changing the hours
from 12 to 1, and the whole cycle started again.

It was interesting to watch but it took a little bit of arithmetic to
work out the time.

Jim


There are always these to keep you busy:

www.timhunkin.com/63_southwold_water_clock.htm

https://www.youtube.com/watch?v=4Pf9YluAU64

--
Davey.
 




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