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Old 29th May 2020, 11:58 pm   #21
rambo1152
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Default Re: BT 'Chiltern' telecom towers

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Originally Posted by AC/HL View Post
My Wife is originally from the Tinshill area. Her Grandmother always referred to the tower as the lighthouse.
I remember when the one near me, at Heaton Park was being built.

The local press dubbed it "The Rocket".
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Old 30th May 2020, 12:24 am   #22
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Default Re: BT 'Chiltern' telecom towers

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The government was always keen to play down the essentially military nature of the Backbone system, though I doubt if the Russians were fooled. The cover story was always that the network was needed to distribute 625 line (and, later, colour) TV signals.
I never heard that one before! My understanding is that it had always been a phone and comms infrastructure, nothing secret, (yeah, maybe some military/government stuff in there too)
All the Backbone towers were classified in the 60s and not shown on Ordnance Survey maps. Bizarrely, this included the Post Office Tower in London which was the tallest building in Britain at the time and had a high profile public restaurant at the top of it. There was and still is a very prominent tower in the centre of Birmingham too.
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Old 30th May 2020, 1:17 am   #23
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Default Re: BT 'Chiltern' telecom towers

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The government was always keen to play down the essentially military nature of the Backbone system, though I doubt if the Russians were fooled. The cover story was always that the network was needed to distribute 625 line (and, later, colour) TV signals.
I never heard that one before! My understanding is that it had always been a phone and comms infrastructure, nothing secret, (yeah, maybe some military/government stuff in there too) and has simply been made redundant since the network was transferred to fibre.
I'm sure though that the fibre network has its military/gov component as well...

Steve.
Spot on Steve.

This was my day job in the 1967-1985 period. The primary use was national TV distribution - actually from the 405 line era onwards. Multichannel inter-city trunk telephony also came along during this period, but as diverse routing for the national underground FDM / coaxial systems. Some of it was referred to as "Backbone", but only in the early planning stages as I remember.
As you said - all on fibre now.

There were some wondrous conspiracy theories around. The view that civilian use was just a front for gov/mil is quite untrue, I'm afraid. (There were discreet military and government radio systems about, but these were not part of the GPO/BT microwave system, and were in completely different locations, run by gov/mil themselves. Look up "ACE High" on Wikipedia for one of the more obvious ones).

The sites and towers are most unlikely to be removed - they are all in prime hilltop sites and in great demand for mobile and fixed comms of all sorts. They are of considerable commercial value!

The website - http://dgsys.co.uk/btmicrowave/
is an excellent source and is an accurate description of the sites and function of the network. I believe it has been compiled from original GPO/BT documentation.
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Old 30th May 2020, 1:55 am   #24
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Default Re: BT 'Chiltern' telecom towers

Thanks John for helping maintain what remains of my sanity. Conspiracy theories do my head in... that's why I wear a foil lined bobble hat at all times!!!

Steve.

PS I just glanced online and found the following quote on the Wiki and given that OS surveys don't happen that often plus the tower was built in 1966 I would say that it's first appearance on a 1971 Os map was about right.

Wiki quote:

It is often said that the tower did not appear on Ordnance Survey maps, despite being a 177-metre (581 ft) tall structure in the middle of central London that was open to the public for about 15 years.[18] However, this is incorrect; the 1:25,000 (published 1971) and 1:10,000 (published 1981) Ordnance Survey maps show the tower.[19] It is also shown in the London A–Z street atlas from 1984.[20]
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Old 30th May 2020, 6:29 am   #25
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Default Re: BT 'Chiltern' telecom towers

Good conspiracy theorists never let facts get in the way of their beliefs. The more strongly something opposes their beliefs, the righter they must be! If someone is desperate enough to try using facts against them, then they must be onto something

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Old 30th May 2020, 10:19 am   #26
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Default Re: BT 'Chiltern' telecom towers

I can't help thinking that leaving the PO/BT tower off the OS maps would have been a rather good way of drawing the attention of the spooks from the other side to it! As said, it seems rather more likely that there was a period between its construction and the next OS survey. Otherwise, this sounds like a classic case of how a "three'n'fourpence" story evolves and becomes urban truth.

Yes, any reasonable structure that pokes its head above other things in the vicinity has considerable appeal (and presumably consequent rental value) for the ever-increasing web of comms, even if obsolescent for its original purpose- at least the crazies will find it difficult to set light to concrete water towers.
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Old 30th May 2020, 10:28 am   #27
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Default Re: BT 'Chiltern' telecom towers

There was some confusion over the status of the Post Office Tower, but the 'Chiltern' towers were generally not shown on maps.

Although the microwave network carried largely civilian traffic all its working life, and was operated by BT, it was conceived and built as a military system. The MOD wanted to get detailed air defence radar plots back to Whitehall and the big command bunker in High Wycombe in real time, and a microwave network was the only way to do this with the technology of the late 50s. It was difficult even with the network - there was lots of custom networking hardware attached to PDP-8 and PDP-11 computers. I was briefly involved in a project to modernise and replace this hardware around 1990, though I had no high level classified clearance. (My report concluded that the proposed solution couldn't cope with the data. I don't know what they finished up building. Maybe the PDPs are still there.)

There was much less separation of the military, government and civilian telecoms sectors in the 60s and 70s than is normal today. Remember, the Postmaster General was a senior cabinet minister.
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Old 30th May 2020, 10:44 am   #28
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Default Re: BT 'Chiltern' telecom towers

There is a BT tower on the top of Purdown in Bristol. This started out as a lattice tower but was replaced with a concrete structure.
http://www.dgsys.co.uk/btmicrowave/sites/210.php
Its also a UFO refuelling stop
https://twitter.com/WeirdBristol/sta...045120/photo/1
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Old 30th May 2020, 11:08 am   #29
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Default Re: BT 'Chiltern' telecom towers

Interesting to note that relaying television signals was a function of the Chiltern and other microwave towers. I thought only the BBC and the (then) ITA looked after this with the likes of Emley Moor, Sutton Coldfield et al.

Apparently, the site at Winter Hill near Bolton relayed Secondary Surveillance Radar data from the CAA radar head at St. Anne's to the control tower at Manchester Airport. This was several decades ago.
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Old 30th May 2020, 1:13 pm   #30
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Default Re: BT 'Chiltern' telecom towers

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Interesting to note that relaying television signals was a function of the Chiltern and other microwave towers. I thought only the BBC and the (then) ITA looked after this with the likes of Emley Moor, Sutton Coldfield et al.
The microwave network was a carrier of signals - not an end-point transmitter.

BT carried the video signals from the various studios to the main station transmitters. At that point BBC/IBA combined the video with the audio and transmitted to the public. (Sound was originally sent over high-quality landline; in later times it went to "Sound in Sync" multiplexing on the video stream). BBC had a small number of microwave links of their own, but the vast majority was BT. The BBC management didn't see themselves as "bit-carriers", I understand.

What is not generally known is that BT also provided network switching to route programme sources to regional transmitters, and this switched as required by daily programme schedules. This was controlled by several BT-manned network switching centres (NSCs). The largest was at the BT Tower (actually in the associated ground-level building). This was a large installation, full of monitors and switching consoles. Not some kind of mock-up as has been suggested. I worked in the most northerly NSC in Aberdeen.
The whole system worked well as a collaborative team structure (BBC/BT/IBA). I wonder if such an organisation would be viable these days, given modern business and management practices ?
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Old 30th May 2020, 1:23 pm   #31
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Default Re: BT 'Chiltern' telecom towers

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There was some confusion over the status of the Post Office Tower, but the 'Chiltern' towers were generally not shown on maps.
The Ordnance Survey has a good reputation for care and diligence. They are also a government/military organisation (the Ordnance bit)

So if something is omitted from their maps, other than for a short while between building the something and the next survey, then it has been removed at official insistence. Some section with plenty of clout.

Perfect proof that it's something hush-hush.

Historically, 'Official Secrets' have been better at keeping information from the British public than from the Russians, considering the number of Russian agents running around in the hush-hush agencies - and that's only the ones we know of!

A Whitehall Farce without G2DQU

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Old 30th May 2020, 1:29 pm   #32
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Default Re: BT 'Chiltern' telecom towers

AWRE at Aldermaston was left off OS maps and as I remember replaced by a couple of streams. The game was given away when an MP asked a question in parliament about it and it was duly reported in Hansard.

A friend who worked for OS told me that the only general directive was that they weren't allowed to show the inside layout of prisons.

Does anyone have copies of maps with the towers omitted?
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Old 30th May 2020, 2:10 pm   #33
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Default Re: BT 'Chiltern' telecom towers

I thought that active military installations were generally left off OS maps.

This led to the situation in this area where a railway branch line ran from the West Cumbrian line at Workington to end in the middle of a field. When the base (and the railway line) closed down, all the disused huts suddenly appeared on subsequent issues of the map.
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Old 30th May 2020, 2:29 pm   #34
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Default Re: BT 'Chiltern' telecom towers

There is a brilliant programme about the Ordnance Survey which showed the Russian maps with all the "classified" bits filled in. Timeshift "A Very British Map", https://www.bbc.co.uk/programmes/b06b36q3 unavailable at the moment.
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Old 30th May 2020, 2:32 pm   #35
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Default Re: BT 'Chiltern' telecom towers

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Originally Posted by paulsherwin View Post
There was some confusion over the status of the Post Office Tower, but the 'Chiltern' towers were generally not shown on maps.
I checked up on the Pye Green one. It's not on a 1966 map, but then it wasn't built until 1966. It's there in quite some detail on a 1:2500 and also there on a 1:10000 where the data is between 1970 and 1973. Now I don't know if it was only the publicly available maps you refer to, but the earliest I have is 1995 and its named as a radio tower on that.
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Old 30th May 2020, 2:32 pm   #36
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Default Re: BT 'Chiltern' telecom towers

When SHMBO and I went for a balloon flight for some (dim and distant) wedding anniversary said balloon went over the Aldermaston weapons factory, it was on the pilots map, I suppose best not to crash into it!
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Old 30th May 2020, 3:22 pm   #37
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Default Re: BT 'Chiltern' telecom towers

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Interesting to note that relaying television signals was a function of the Chiltern and other microwave towers. I thought only the BBC and the (then) ITA looked after this with the likes of Emley Moor, Sutton Coldfield et al.
The microwave network was a carrier of signals - not an end-point transmitter.

BT carried the video signals from the various studios to the main station transmitters. At that point BBC/IBA combined the video with the audio and transmitted to the public. (Sound was originally sent over high-quality landline; in later times it went to "Sound in Sync" multiplexing on the video stream). BBC had a small number of microwave links of their own, but the vast majority was BT. The BBC management didn't see themselves as "bit-carriers", I understand.

What is not generally known is that BT also provided network switching to route programme sources to regional transmitters, and this switched as required by daily programme schedules. This was controlled by several BT-manned network switching centres (NSCs). The largest was at the BT Tower (actually in the associated ground-level building). This was a large installation, full of monitors and switching consoles. Not some kind of mock-up as has been suggested. I worked in the most northerly NSC in Aberdeen.
The whole system worked well as a collaborative team structure (BBC/BT/IBA). I wonder if such an organisation would be viable these days, given modern business and management practices ?
I learn a lot on this site! Were the NSCs for both BBC and ITV stations?
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Old 30th May 2020, 4:02 pm   #38
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Default Re: BT 'Chiltern' telecom towers

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When SHMBO and I went for a balloon flight for some (dim and distant) wedding anniversary said balloon went over the Aldermaston weapons factory, it was on the pilots map, I suppose best not to crash into it!
The NATS map https://www.aurora.nats.co.uk/htmlAI...hics/27357.pdf says the airspace over and for some distance around AWE Aldermaston is Restricted (ref R101). You might have been OK if you were flying out of Brimpton, who have a special exemption https://www.brimpton-airfield.co.uk/...tion/r101-zone, but I'd be very surprised if any flying at typical balloon heights over the site itself would have been tolerated. On the few occasions I've been in and out of AWE the weapons in the hands of the security people there have left me in no doubt about their attitude to uninvited visitors.

Getting back to the topic, I did check to see whether the Stokenchurch tower was on my 1974 OS map of Oxford (sheet 164). It wasn't, but the reason was that it is just off the east edge of the sheet. Does anyone have sheet 165 ?

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Old 30th May 2020, 4:34 pm   #39
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Default Re: BT 'Chiltern' telecom towers

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I did check to see whether the Stokenchurch tower was on my 1974 OS map of Oxford (sheet 164). It wasn't, but the reason was that it is just off the east edge of the sheet. Does anyone have sheet 165?
OS maps are available online, scroll left a bit from Stokenchurch and a mast is shown between Hill Farm and Kiln Farm just north of the M40, which (from my distant memories of driving that way in the past) seems about right.

I did try to include the link to Stokenchurch itself, but it contains square brackets, which confused the BBcode, so I reproduce it below:
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Old 30th May 2020, 4:43 pm   #40
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Default Re: BT 'Chiltern' telecom towers

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Quote:
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Originally Posted by Sparks View Post
Interesting to note that relaying television signals was a function of the Chiltern and other microwave towers. I thought only the BBC and the (then) ITA looked after this with the likes of Emley Moor, Sutton Coldfield et al.
The microwave network was a carrier of signals - not an end-point transmitter.

BT carried the video signals from the various studios to the main station transmitters. At that point BBC/IBA combined the video with the audio and transmitted to the public. (Sound was originally sent over high-quality landline; in later times it went to "Sound in Sync" multiplexing on the video stream). BBC had a small number of microwave links of their own, but the vast majority was BT. The BBC management didn't see themselves as "bit-carriers", I understand.

What is not generally known is that BT also provided network switching to route programme sources to regional transmitters, and this switched as required by daily programme schedules. This was controlled by several BT-manned network switching centres (NSCs). The largest was at the BT Tower (actually in the associated ground-level building). This was a large installation, full of monitors and switching consoles. Not some kind of mock-up as has been suggested. I worked in the most northerly NSC in Aberdeen.
The whole system worked well as a collaborative team structure (BBC/BT/IBA). I wonder if such an organisation would be viable these days, given modern business and management practices ?
I learn a lot on this site! Were the NSCs for both BBC and ITV stations?
As far as memory goes, ITV switching was carried out by BT (since the programme providers were all separate companies). The BBC carried some switching themselves, but their links also routed via the NSCs. This allowed maintenance, cross patching and possible re-routes under fault conditions.
The active channels were quality monitored at the NSCs by BT - and any loss or signal degradation had to be attended to within seconds ! Of course they paid BT very serious money for this...
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