>>A press release from the GPO suggests aluminium was first used in 1969...

Thanks for the confirmation, the press release clearly mentions, as I reported, aluminium cables were first used in the 50s. Where the boffins of the time specced 0.8mm conductors. This release is mainly about the release of 'connector wire insulated 1' crimps to mitigate the cutting back to the 0.5mm gauge against the advice of the original research.

Today CWI1 crimps are probably worse for broadband than the ali cable! They certainly are being replaced on sight.

But money talks and if you can maintain a 500ohm single wire resistance with a cheaper roll out, why wouldn't you? It was all about a loop seizing a dial tone in them days. In 1965 the PO were projecting telephone ownership could reach 50% by 1980! They had a lot of expansion work to do.

Today Virgin and OLOs are putting tubes straight in the ground with no ducts. Crazy short term thinking at 100mm below the tarmac. It will cost them in the long term.as they get regularly damaged. It's already happening.

I was wrestling with a 800pr 0.9mm copper cable the other day. 1937 vintage. In them days the exchange was a lot further away so heavier poundage was essential. Monster cable, duct filler, larger than a modern 4800. Cut into the 'new' 60s exchange later in it's life and probably giving todays broadband subscriber who declines to move to FTTC top service. Sometimes old stuff is better!

Edited by deleted (Sat 19-Aug-17 22:25:44)

In reply to a post by partial:

>>A press release from the GPO suggests aluminium was first used in 1969...

Thanks for the confirmation, the press release clearly mentions, as I reported, aluminium cables were first used in the 50s.

It does indeed confirm that, but also confirms they were only experiments that far back. "Patient research" continued until a "breakthrough in the mid 60s". Will any of that experimental stuff still exist in the network?

I found an article in the New Scientist 1964 that maybe describes that patient research: the use of aluminium in an "8 year experiment". https://goo.gl/LMHja9

That was a 54-pair line between Dover and Deal; it describes the polythene sheath as less resistant to water than lead, and looks like it took part in experiments for cable pressurisation (becoming standard from 1963?). The distance (8 miles) also suggests it wasn't access network, but perhaps a junction cable.

The 1969 press release says that "changeover happened eight months ago" - in early 1969 - but without stating exactly what changed over. The context of the release relates to the access network specifically. The only realistic way to interpret *what* changed over is the use of aluminium in the live access network.

Perhaps, though, trunk and junction cables started to use aluminium at an earlier date.

Is the CWI1 anything like today's jelly crimps? The NS's article describes something rather strange-sounding.

In reply to a post by partial:

In 1965 the PO were projecting telephone ownership could reach 50% by 1980! They had a lot of expansion work to do.

They did better than that!

In 1965, it seems that there were only 400,000 homes with phones (though there were a lot more businesses, and a lot more phones); that's 2% of the 17m homes of the day.

By 1980, they'd reached 14.3m homes out of the 20m that then existed. Something like 72%.

By 1995, they'd reached 21m homes out of the 23m that then existed. Something like 90%.

In reply to a post by partial:

Today Virgin and OLOs are putting tubes straight in the ground with no ducts. Crazy short term thinking at 100mm below the tarmac. It will cost them in the long term.as they get regularly damaged. It's already happening.

Especially when you watch the behaviour of existing utility companies, and what they do. When you see the water and gas companies choosing to re-use old pipes by lining them on the inside with new plastic pipes, it has to tell you something.

In reply to a post by partial:

I was wrestling with a 800pr 0.9mm copper cable the other day. 1937 vintage. ... Sometimes old stuff is better!

If you're lucky, you're lucky!

In reply to a post by partial:

>>A press release from the GPO suggests aluminium was first used in 1969...

That press release was suggesting that all cables could be aluminium by the end of 1969, but it patently didn't happen to that extent

The reason why could be related to one other point made in the article: Aluminium cables were only 10% cheaper than copper.

Yes, copper prices reached peaks in 1968, 1970 and 1974. Aluminium hit peaks at the same time too, but then stood relatively steady in the rest of the seventies. However, copper prices fell back much more, and then kept falling in the rest of the seventies. More than enough to account for the 10%.

Perhaps, then, the savings turned out to be fleeting.

Thanks. Interesting article. 54pr is pretty much always going to be a junction. I have never seen an aluminium junction. Doesn't mean they never existed. Just means I never saw one.

Prior to mid 90s the various 'districts' were run as pretty much self contained independent businesses and had their own ideas. I would expect coax junctions came along and put pay to them.

CWI1s were phosphor bronze compression crimps, ali friendly. Known as Blue Beans nowadays, although they were also purple and ungrease filled white originally.

Rather than previously twisted and sleeved joints, really bad for ali, they used a calibrated tool to compress and puncture insulation, really good for ali.

Jointers tools became uncalibrated and old school would strip, twist and then crimp. Or perhaps they would twist and crimp with the back of their cutters. Really bad for broadband. Removed on sight nowadays. Stopped using them late eighties.

Similar compression connectors 'MJ4s' used on main side into the mid nineties. same problem, much more difficult to get rid of on a cable with thousands of pairs and no slack!

State of the nation 1965 for telecom saddos! www.samhallas.co.uk/repository/documents/local_lines.pdf

In reply to a post by partial:

State of the nation 1965 for telecom saddos! www.samhallas.co.uk/repository/documents/local_lines.pdf

Fascinating! A great addition to the stats collection. Most information I had tended to peter out prior to 1970.

Unfortunately, it means a bit of my earlier data is rather incorrect, but armed with this (and further searching), I'll go back and fix that.

Elsewhere in this thread, there is a set of statistics available. From this (and other sources), I've been able to determine that my first statistic below is incorrect:

In reply to a post by WWWombat:

In 1965, it seems that there were only 400,000 homes with phones (though there were a lot more businesses, and a lot more phones); that's 2% of the 17m homes of the day.

By 1980, they'd reached 14.3m homes out of the 20m that then existed. Something like 72%.

By 1995, they'd reached 21m homes out of the 23m that then existed. Something like 90%.

Better data shows:
- 1958, 16% of 16m homes had telephone = 2.6m
- 1965, 21% of 17.4m homes had telephone = 3.7m
- 1970, 35% of 18.3m = 6.4m
- Figures for 1980 and 1995 remain correct

So, In 1965, it appears (from various sources), there were
- 3.7m residential connections
- 6.2m exchange connections
- 8.8m pairs in the access network (30% spare)
- 10 million telephones

That�s a great read! I particularly liked the section �A New Cabinet� which describes what we now know as shelf cabinets. An ingenious invention apparently! We all despise them now as although they put the D-sides through numbered holes no one thought it a good idea to also do the same for the E-sides! So they just come up in the middle in a complete mess! There�s still plenty of shelf cabinets about too.