Posts Tagged With: volunteering

Telegraph Road – Why Electric Motors made the Internet Possible (Part 2)

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Where the cables emerge in a beach hut

 

 

So, your electrical signal has crawled through a thousand miles of cable under the sea, and emerged, breathless, in need of regeneration.

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Once you see what was done, you can see that it was genius and, as the best ideas often are, simple. If you know when each bit (here representing a dot or a dash) is going to start, you can then make a reasonable guess as to what the original bit was. Provided there is a quite a big difference between the signal level for a dot and a dash, you should be able to regenerate the signal accurately. Regeneration hinged on knowing exactly when each bit started…

So, what could be used to reliably keep time in new electric Victorian world? A motor, that’s what. Use a clock to produce a pulse of electricity to drive a motor round and then everything could be synchronised, like the steam-powered factories that used belts to drive the machinery – only this was a pulse that drove everything in unison.

The dotted lines represent the pulses that are synchronised across the whole telegraph network, from master clocks at each relay sending/receiving station. The clocks were themselves synchronised to all the others using signals sent at the beginning of the day. There was also a speed adjustment on the interpolator to allow the speed of its motor to be tweaked to ensure absolute precision. Once you were synchronised, it was all straightforward.

  1. You know when the character is supposed to start because your master clock tells you. You wait for half a turn of your motor – this puts you right in the middle of the incoming bit.
  2. You then ask the question – is this signal above or below the reference (plus or minus a few microvolts to allow for noise)?
  3. If it is above, you set a high voltage (usually 100 Volts) on your outgoing cable.
  4. If it is below, you set a low voltage (-100 Volts).
  5. Bingo! One regenerated signal now able to crawl through the next bit of wire.

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This was all done using a motor and relays. If you are familiar with Terry Pratchett’s book “Going Postal”, you may recognise a distinct “Clacks” feel to this. The thing is, this was the start of the idea of long-distance near-instant communication being made real. It was also the beginning of the rise of the (electric) machines. Operators, previously required to re-key the messages were now replaced by wires and electrons. And it turns out, wires and electrons were hopeless at sports. On Ascension Island, so few engineers replaced the 30 or so operators, that team games had to be ditched in favour of singles tennis.

A new age was dawning, where the world was becoming connected, where information would be the new empire to conquer. At the heart of this revolution was, at least to begin with, the humble electric motor.

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Either the author is really tall or this is a diddy telegraph pole. I’ll let you, dear Reader, decide…

 

oOo

With huge thanks to John and Ravy (sorry to have misspelt your name here!) and, indeed, everyone who helps run the Porthcurno Telegraph Museum.

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Categories: computers, repair, Sustainable Stuff | Tags: , , , , , | 4 Comments

Telegraph Road – Why Electric Motors made the Internet Possible (Part 1)

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Ravy patiently explaining how an interpolator works

One of the things I wanted to do on my return to Cornwall this year (it seems you can’t be banned from the county for dipping a Cornish pasty in a bottle of sauvignon so I was able to go back) was to revisit the Telegraph Museum at Porthcurno and talk with the volunteers who maintain the old telegraphic equipment. Many are ex-telegraph engineers themselves so know a thing or a hundred about telegraphs.

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John patiently explaining to me how a line balancer works

Imagine: it’s a bit before 1870 and, being a wealthy Victorian, you decide to connect the new-fangled telegraph-whatchamacallit to the rest of the world (or The Empire as it was known then). You find a nice quiet cove and haul the first cable, going all the way to Portugal, onto the sand. Well, OK, YOU don’t personally because you have people to do that sort of thing.

And it all worked very well, with Morse code messages being sent back and forth from America, India and, of course, Portugal. Problem was that the signal, having crawled along thousands of miles of underwater cable, was feeling a bit washed out by the time it reached anywhere, so relay stations were built along the routes, which is why Britain and other Western European countries became very interested in those tiny Caribbean islands – it wasn’t just they fancied sunny holidays at the Empire’s expense. Messages would arrive, tired and a bit worse for wear, then be retyped (re-keyed in Morse parlance) onto the next bit of cable and so on. Lots of people were needed which was fine because there were a lot of people who fancied a holiday at the expense of the Empire.

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More patient explaining

Of course, if there was one thing Victorians were in love with, it was the idea of automation. If there were two things, then the other would have been sunny holidays at the expense… oh, you know the score. So, the idea of REGENERATION was born, long before Doctor Who made it a handy way of changing the actor at the end of a series.

The issue was, as with great comedy, that of timing. How could you synchronise and also understand an exhausted signal from thousand of miles away? It needed some kind of clock and rejuvenating in some way.

And that involved a motor. And another blog post…

oOo

Categories: computers, repair, Sustainable Stuff | Tags: , , , , , | 4 Comments

Of Mice and Shrews

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Wood mouse? Of course, it would.

I took part in a Dormouse survey at Denmark Farm the other day. It was a fabulous day, six hours spent walking across the whole site checking the 45 nest boxes, scattered throughout the site, for signs of dormice. These small mammals are losing their habitat quicker than you can say “Cute!” and have an important place in the ecosystem (along with pretty much everything else except slugs and most politicians).

None have ever actually been found at Denmark Farm but, following a tell-tale nibble mark on a nut found in one of the fields, 6-monthly surveys of the mammal nesting boxes have been carried out. Would we find one this time?

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A cotton bud. Or a pygmy shrew.

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A duck-billed Platypus. Or a pygmy shrew.

No. But these Wood mouse and pygmy shrew pictures were just too cute not to share.

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A Wood mouse trying to impersonate a pygmy shrew.

Maybe there will be dormice in the spring…

oOo

Categories: gardening, Sustainable Stuff, wildlife | Tags: , , , , | 8 Comments

A Busy Sunday

Play Yurt Down time lapse film

Click to play “Yurt Down” time lapse film

Yesterday was Sunday which, when you are self-employed, has no special meaning to it. So, my Sunday started with gardening, in particular the only gardening I can be trusted to do on my own, that being moving soil. Our new raised bed (built with the Limery) is now ready for some squashes…

After that exertion, I needed to sit down with a cup of coffee and a bacon butty, which was exactly what happened. And locally-produced bacon, to boot.

THEN… I put together the time lapse film of myself and a few volunteers taking down the yurt at Denmark farm. This is something I have blogged about before, but I thought it might be fun to produce a time lapse film of the event. I intend to make another one when we put the thing up next spring. I discovered that my trusty camera has a setting to tell it to take a picture every so often so, in true pioneering spirit, I decided to give it a go. Click on the picture at the top to watch the result on Youtube.

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A guitar with, frankly, too many strings to its fretboard…

Having pieced together the film, I decided to record a simple soundtrack to accompany it. I used this as an excuse to play the guitar in the picture above – I bought it about five years ago and haven’t really quite mastered yet. Listening to my efforts now, I think I have quite a way to go!

Surprisingly, I finished composing (if that’s what it can be called) and recording “Yurt Down Blues”, all one minute 6 seconds of it, in time for a cup of tea and a look at the crossword.

Sunday’s can be quite satisfying sometimes!

oOo

Categories: camera | Tags: , , , , | 7 Comments

Yurt-y Dancing

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Walls have (Volunt)eers

26th April. Oh yes, it must be late spring because it is time to put the Denmark Farm yurt up again!

So, a brave band of volunteers braved the lovely weather – er, and the five minutes of snow – to erect the yurt that, this year, has a completely new canvas which includes an extra bit that goes over the top to help protect the main canvas from the elements. Or so I was told.

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Gary wanting to know why I have abandoned my post

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Crowning Glory

A gang of six of us made short work of putting up the walls and fixing the crown. A yurt is a truly wonderful piece of engineering and has a certain beauty, even ‘naked’ without its canvas. But not very weatherproof.

After a short break for coffee and lemon drizzle cake, we embarked on fitting the canvas.

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The old canvas (poor thing, I think it was about six years old) was beginning to look a bit tired and, although there was still a few years left in the material, it was decided that a new one was in order. The new yurt was made by someone in Pembrokeshire who agreed to pass the old one onto Calais where it will be used in the refugee camp there. How great is that?

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The Yurt has got its hat on… er, nearly

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Just needs its cap on now

Fitting the canvas, the green bit (which is made of similar material to a ground sheet and so quite heavy) and the window on the top took a bit of finagling and involved the use of a really clever fast release knot, which seemed like to magic to me (one end of the rope tightened the knot, the other undid it).

We needed some new pegs to attach the guy ropes to, so made these with the help of a shave horse. A shave horse is a great tool, you can make one yourself pretty easily and it does not involve shaving, horses, or shaving horses.

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Making proper tent pegs

 

With the new yurt in place, it was time for tea and cake. Again. You can see why volunteer days are popular!

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Ready for the arduous tea-drinking stage

Fancy spending a night or two in it? Go on! Check out http://www.denmarkfarm.org.uk/eco-campsite/ for more information.

oOo

 

 

Categories: recycling, Sustainable Stuff, Travel | Tags: , , | 4 Comments

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