Valved undersea telephone repeaters - UK Vintage Radio Repair and Restoration Discussion Forum

Tractorfan · 17th Jul 2010, 8:12 pm

Today I was struck by a sudden curiosity about those telephone repeaters that used to lie on the seabed and were kept warm by the valves within. The valves were wired in & I often wondered how they worked, how they were powered (it's an awful long way to send 6.3volts

), how they were made and tested, etc., etc., etc. Is there a website about them? Thanks in advance.
Sorry if this isn't the place but I don't know where else to post it.
Cheers de Pete

McMurdo · 17th Jul 2010, 8:31 pm

Further reading here:
http://www.atlantic-cable.com/

audiomagpie · 18th Jul 2010, 8:56 am

This place is well worth a visit if you're ever down in Cornwall:

http://www.porthcurno-telegraph-museum.org.uk/

I went a few years ago, they have some old valve reapeaters on display, with sections cut away, to reveal the innards and insulation/construction methods etc.

They also have working spark transmitter and a fantastic collection of telegraphy equipment.

Greg

Tractorfan · 19th Jul 2010, 11:32 am

Hi. Thanks for the info. I visited Porthcurno museum a few years ago but I think the section of it was closed to the public for refurbishment that housed the repeaters. Thanks again.
Cheers de Pete

daviddeakin · 19th Jul 2010, 12:23 pm

Here is a paper written about the special construction methods used for repeater valves and capacitors:

http://www.dalmura.com.au/projects/S...ne%20cable.pdf

kalee20 · 19th Jul 2010, 1:21 pm

Fascinating that new-fangled plastic film capacitors were ruled out in favour of paper (even though the paper did have known shortcomings).

And so were ferrites. But then, today we have the benefit of hindsight!

Truly, people who designed and built these, should feel proud of themselves.

21st Jul 2010, 9:01 pm

Repeaters, even now, are powered in series using constant current, a few kV is sometimes needed for long runs. With a power supply at either end (and I assume 2 diodes) redundancy is built in.

DAVEHALL · 21st Jul 2010, 11:17 pm

Tat 1 was power fed with about 4.5KV- and power from the States . It was a two cable system with series power feed , and a tap taken to the heaters .
Cantat one was a single cable with a series power feed ,but with directional filters -both ends were fed from Oban and the states ,on an approx 3.8kv feed .
The Middlesbrough Gotenburg system was a prototype for Cantat 1 .
Fortunately , I'm one of the few left that will admit to being part of the Transatlantic cable thingy .

Ask ,and if memory permits ,I'll give you an answer .

ppppenguin · 21st Jul 2010, 11:42 pm

Good to know that there are still folks around who worked on TAT1.

I've got a copy of the IEE papers about TAT1. They were the proceedings of a joint IEE/IRE conference held in London and New York via TAT1 to celebrate it's inauguration. Fascinating stuff. Dave, were you involved with the conference?

Interesting thought: It took almost 100 years from the first transatlantic telegraph cable to the first transatlantic telephony cable.

Richard G4DYA · 26th Jul 2010, 12:09 am

The whole of the January 1957 edition of The Post Office Electrical Engineers' Journal (Vol 49 part 4) is about TAT1, with dozens of technical articles about many aspects of it.

17th Jul 2010, 8:12 pm	#1
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Valved undersea telephone repeaters Today I was struck by a sudden curiosity about those telephone repeaters that used to lie on the seabed and were kept warm by the valves within. The valves were wired in & I often wondered how they worked, how they were powered (it's an awful long way to send 6.3volts ), how they were made and tested, etc., etc., etc. Is there a website about them? Thanks in advance. Sorry if this isn't the place but I don't know where else to post it. Cheers de Pete __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

17th Jul 2010, 8:31 pm	#2
McMurdo Dekatron Join Date: Jun 2009 Location: Staffordshire Moorlands, UK. Posts: 5,271	Re: Valved undersea telephone repeaters Further reading here: http://www.atlantic-cable.com/ __________________ Kevin

18th Jul 2010, 8:56 am	#3
audiomagpie Heptode Join Date: Apr 2003 Location: Rugby, Warwickshire, UK. Posts: 824	Re: Valved undersea telephone repeaters This place is well worth a visit if you're ever down in Cornwall: http://www.porthcurno-telegraph-museum.org.uk/ I went a few years ago, they have some old valve reapeaters on display, with sections cut away, to reveal the innards and insulation/construction methods etc. They also have working spark transmitter and a fantastic collection of telegraphy equipment. Greg __________________ Greg BVWS committee chairman

19th Jul 2010, 11:32 am	#4
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,183	Re: Valved undersea telephone repeaters Hi. Thanks for the info. I visited Porthcurno museum a few years ago but I think the section of it was closed to the public for refurbishment that housed the repeaters. Thanks again. Cheers de Pete __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

19th Jul 2010, 12:23 pm	#5
daviddeakin Hexode Join Date: Apr 2007 Location: W Yorks, UK. Posts: 407	Re: Valved undersea telephone repeaters Here is a paper written about the special construction methods used for repeater valves and capacitors: http://www.dalmura.com.au/projects/S...ne%20cable.pdf

19th Jul 2010, 1:21 pm	#6
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,082	Re: Valved undersea telephone repeaters Fascinating that new-fangled plastic film capacitors were ruled out in favour of paper (even though the paper did have known shortcomings). And so were ferrites. But then, today we have the benefit of hindsight! Truly, people who designed and built these, should feel proud of themselves.

21st Jul 2010, 9:01 pm	#7
Guest Guest Posts: n/a	Re: Valved undersea telephone repeaters Repeaters, even now, are powered in series using constant current, a few kV is sometimes needed for long runs. With a power supply at either end (and I assume 2 diodes) redundancy is built in.

21st Jul 2010, 11:17 pm	#8
DAVEHALL Retired Dormant Member Join Date: Jan 2010 Location: Coventry, Warwickshire, UK. Posts: 339	Re: Valved undersea telephone repeaters Tat 1 was power fed with about 4.5KV- and power from the States . It was a two cable system with series power feed , and a tap taken to the heaters . Cantat one was a single cable with a series power feed ,but with directional filters -both ends were fed from Oban and the states ,on an approx 3.8kv feed . The Middlesbrough Gotenburg system was a prototype for Cantat 1 . Fortunately , I'm one of the few left that will admit to being part of the Transatlantic cable thingy . Ask ,and if memory permits ,I'll give you an answer . Last edited by DAVEHALL; 21st Jul 2010 at 11:23 pm.

21st Jul 2010, 11:42 pm	#9
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Valved undersea telephone repeaters Good to know that there are still folks around who worked on TAT1. I've got a copy of the IEE papers about TAT1. They were the proceedings of a joint IEE/IRE conference held in London and New York via TAT1 to celebrate it's inauguration. Fascinating stuff. Dave, were you involved with the conference? Interesting thought: It took almost 100 years from the first transatlantic telegraph cable to the first transatlantic telephony cable.

26th Jul 2010, 12:09 am	#10
Richard G4DYA Diode Join Date: Feb 2010 Location: Staffordshire Posts: 3	Re: Valved undersea telephone repeaters The whole of the January 1957 edition of The Post Office Electrical Engineers' Journal (Vol 49 part 4) is about TAT1, with dozens of technical articles about many aspects of it.