[time-nuts] I now have a clock accurate to 10E-6!!!

Jim Palfreyman jim77742 at gmail.com
Tue Aug 26 22:14:30 EDT 2008


Well here's the photo I promised. I didn't take my time and I didn't use a
tripod. But you get the idea.

So on the left we have the Siemens Master Clock with the 14mm Riefler
pendulum. In the rack from the top we have:

1) 5MHz OCXO backup for the speaking clock. This was used to hold the time
if the signal was lost from the central caesium master clock in Victoria.
It's a disciplined oscillator and was steered by a 1 KHz tone (based on the
caesium reference) down a phone line.

2) Another 5MHz backup unit in case the first failed.

3) The main speaking clock unit. You can set the time, date, daylight
savings and leap seconds from here.

4) A simple switch to control which speaking unit was "live".

5) The actual speaking unit. Converts time into voice and sends it back to
the main clock unit. Should be two of these, but I only have one.

5) HP 5370B timer counter.

6) HP 3370B function generator.

7) Murray Greenman's GPS clock. It has a 10811 inside and provides the 1PPS
for the speaking clock. It also emulates the sound pips of VNG - the now
closed Australian short wave time service. At the press of a button it does
the announcements that used to happen every 15 minutes "This is VNG,
Lyndhurst, Victoria, Australia on 4.5, 7.5 and 12 MHz. VNG is a standard
frequency and time signal service of the Australian Telecommunications
Division". It does it all in the original voice that the older Australian
Ham Radio people know and love. That's because I have the original master
tape of that recording and I have digitised it.

8) A lovely old HP nixie tube frequency counter. Still works as if it was
bought yesterday.  Has a clever device on the right to read frequencies up
to 3GHz. All three of the HP counters and oscillators are of course fed off
a GPS based frequency reference (HP Z3815A hidden at the back of the rack).

9) This is a part of the speaking clock that I don't use. It takes the time
from the main speaking clock unit (3) and creates pips (for example the six
pips per hour that was used on the radio stations) and then distributes it
down phone lines.

10) This unit receives and decodes the master time signal from a
transmission unit that used to be in Victoria (connected to the caesium
clock). Since I don't have the transmission unit I cannot use this. I've
hot-wired the 1PPS directly into the speaking clock instead.

11) No idea. Came in the rack. Something to do with two-tones. Not used and
doesn't power up.

To the top right of the rack is the rather nice "mesmeriser" clock kit from
Jaycar. It is, of course, sychronised. Below that is a three digit display
showing UTC milliseconds. The speaking clock has YY MM DD HH MM SS (in unit
5 in the rack) and so I thought milliseconds was just essential to complete
it.

To the right and slightly cropped is an old grandfather clock mechanism
which I'd hoped to steer via a 1PPS. However the pendulum swings at some
bizzare multiple of seconds so I gave up on it. Now I have my Siemens Master
Clock I don't care...

So there you go - I hope some of you find this post interesting!

Regards,

Jim


2008/8/26 Neon John <jgd at johngsbbq.com>

> On Mon, 25 Aug 2008 17:40:14 +1000, "Jim Palfreyman" <jim77742 at gmail.com>
> wrote:
>
> >Hi Folks,
> >
> >Well I've had the best weekend since I've just acquired a pendulum clock
> >that used to be a telecommunication time standard in the 50s.
>
> Nice.
>
> I'd love to have a photo of that with both the clock and the rack of HP
> goodies both showing.  Move to the right a little, maybe use a tripod and
> turn
> off the flash to get more uniform lighting and the result would be a
> wonderful
> contrast between old and new.
>
> John
> --
> John De Armond
> See my website for my current email address
> http://www.neon-john.com
> http://www.johndearmond.com <-- best little blog on the net!
> Tellico Plains, Occupied TN
>
> *fas-cism* (fash'iz'em) n. A system of government that exercises a
> dictatorship of the extreme right, typically through the
> merging of state and business leadership, together
> with belligerent nationalism.  -- The American Heritage Dictionary, 1983
>
>
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