I barely paid attention in my lectures, he was really boring. Optical comms was only half the module, the other half was satellite comms. As the exam was answer 3 out of 4 question I choose to revise more satellite than optical and answer 2 sat and 1 optical question. Luckily the optical one was a very wordy question about describing the parts of a WDM system and Add/Drop multiplexers.
Undersea Cables
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I barely paid attention in my lectures, he was really boring. Optical comms was only half the module, the other half was satellite comms. As the exam was answer 3 out of 4 question I choose to revise more satellite than optical and answer 2 sat and 1 optical question. Luckily the optical one was a very wordy question about describing the parts of a WDM system and Add/Drop multiplexers.
Tell me about it.
Its all this TDM WDM and DWDM bands and that. Since I'm doing physics, we spent a lot of time looking at equations.
Optical splicing.
I did some of the capacity planning for Level 3's backbone some know something about the topology of these networks. When I first got into it, I was always amazed about the lack of capacity heading east from London. Crazy, huh?
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Also if you think this is amazingyou should look at oil and gas projects like BP King (Installed by the Normand Cutter in the GoM) and BlueStream/Greenstream and the new rigid pipeline going from Russia all the way around the Baltic and into Germany, which is called Nordstream.
KaHn
KaHn
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I can't even begin to imagine how massive the undertaking would have been to lay it in 1901. Must have been quite scary going out there not knowing what would happen or if it would work once you had laid it.
The repeaters used to boost the signal are cool bits of kit, they look like a big torpedo. The cable goes in one end the signal is boosted and comes out of the other. Obviously these "repeaters" require power to do their stuff, this is carried by the coaxial sheath in the cable.
Now the clever bit, when they get a cable cut they can tell where it is by measuring the resistance, they can then tell the cable has broken.
HEADRAT
Now the clever bit, when they get a cable cut they can tell where it is by measuring the resistance, they can then tell the cable has broken.
HEADRAT
i know a scrap metal dealer who had to get a 40 mile cable out 
also pits just buried them the amount of money in pit cable is astounding.seen a 1 mile cable dragged out of one local pit near me.
to think last year at one point copper best bright wire was £4000 a ton (best ever) was silly. if you are good at stripping cable you can do it faster than the machines made for it.
burning cable which used to be best way and cheapest to get to the end product cheapest is now a prison sentence if caught.
also pits just buried them the amount of money in pit cable is astounding.seen a 1 mile cable dragged out of one local pit near me.
to think last year at one point copper best bright wire was £4000 a ton (best ever) was silly. if you are good at stripping cable you can do it faster than the machines made for it.
burning cable which used to be best way and cheapest to get to the end product cheapest is now a prison sentence if caught.
Isambard Kingdom Brunel's magnificent steamship (the Great Eastern) was used to lay some of the eaerliest undersea cables. It's amazing what they could achieve, even in the 19th Century.
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Having worked extensively with satellite comms and internet access I can tell you that on average geostationary satellites offer at best around 600-700ms latency, however they can stream well in excess of 2mbits if you're willing to pay for it. Some customers had their own dedicated channels for uplinks too, but we're talking 5figure subscription per month.
As for the underwater cables I've seen the boats that fix them, it's amazing to watch.
As for the underwater cables I've seen the boats that fix them, it's amazing to watch.
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Yeah a bit like in fibre optics they use an optical time-domain reflectometer to pin point the area of the break it's an amazing bit of kit.
Another interesting fact I picked up when visiting Hibernia Atlantic was that these undersea cables don't carry 100's of fibres, if you think about it's pretty obvious why. The repeaters would have to be enormous and with current multiplexing tech there is more than enough capacity in just a few fibres.
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Unless your in France or somewhere with FTTH.
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The best you'll ever get is 36ms - that's how long light will take to travel from London to New York and back again (combined round trip of 7000miles). Add in server latency and signal boosters and 100ms looks quite reasonable.
there was once a documentary about the people who fix the cables on one of the documentary channels.
they basically just cut out a few metres from each side of the snapped area and join a new peice of cable between them