Custodian for the future.

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Custodian for the future.

Postby Scaleyback » Sat Feb 16, 2019 9:34 am

It's not mine you see.. Well technically I own it, but it's more than that. I just maintain the system, until it is time to hand over to the next person. Not only is it one of my life's works and passions, but it lives and moves and also enthralls those who see it.
Today, the same job can be done with and aerial and an Arduino board, but there is no interest, no 'life' in that, nothing to get excited about or wonder at.

It is a long story which i won't go into now, but during my time working at the PO (later BT), I ended up looking after the exchange clock system. When the Strowger exchanges got decommissioned in the 1990's, most went for scrap, but I went around acquiring what I could and after some years I was finally able to build up a representative system, which includes automatic daily synchronisation.


The sounds change, a clock will go in and then out of sync with one of the others. The sound of the relays alter for the same reasons. That 6 second one, lower right relay unit is a little loud... Should I go check the spring tensions?

Yes, you can do it everything here with an Arduino or two, but show me the passion in that...

(Ok, bit of a dramatic introduction, but I got halfway through typing, "Hello, I am Simon and I have a GPO clock system..." When I thought, "Oh, to hell with that!"). So hi to everybody and it is so nice to see this stuff preserved and hopefully working.
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Joined: Fri Feb 15, 2019 11:16 pm

Re: Custodian for the future.

Postby Lucien Nunes » Sun Feb 17, 2019 11:01 am

Hello and welcome. That looks like an effective and reliable way to tell the time! Do tell about the method of synchronisation...
Black was always meant to be a phase. The neutral phase.
Lucien Nunes
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Joined: Fri Apr 18, 2008 12:26 am

Re: Custodian for the future.

Postby Scaleyback » Mon Feb 18, 2019 12:21 pm

Originally, the clocks received a pulse relayed from the Royal Observatory at greenwich, over the telegraph network which forcibly corrected the positions of the 30 second count wheels once a day, typically at 10am. The clock system would then correct any 1 second clock at the top of the next hour.

The telegraph time network closed a long time ago, but I have an MSF receiver and pulser card, one output of which sends a 1 second daily pulse to operate the synchronisers in the master clocks, with the system then correcting the ! second clocks one hour later.
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Joined: Fri Feb 15, 2019 11:16 pm

Re: Custodian for the future.

Postby Kevin Wood » Wed Feb 27, 2019 11:17 am

Fascinating. Makes my home made nixie clock look decidedly lacking in commitment!
Kevin Wood
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Joined: Tue Aug 11, 2009 9:50 am
Location: Four Marks, Hampshire

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