Exciting development!

[Mark Beard 1Participant @markbeard1]

Have to be quick, off to Post Office with sufficiently small bulb for your needs!

 

By my reckoning, the line impedance would have been 1 ohm per kilometer, so that’s 5000 ohms for the whole cable. But there would also be huge capacitance (haven’t worked that out yet) but the result of both resistance and capacitance is a considerable delay in the signal, which changes very slowly at the receiving end.

 

There’s a lot to these signalling issues, so much so that the maths to solve it all eventually led to the equations of James Clerk Maxwell which paved the way for Einstein’s theory of Special Relativity.

 

Bob, this is heady stuff indeed!

[Bob Abell 2Participant @bobabell2]

Ashley

 

The drum is inside the hull…..So was GE`s but GE`s cable was stored in giant tanks about 60 foot diameter.

 

Dermis. thanks for the info from the past!……….17 hours to transmit?…….Geeezzzzz!

 

The first test on the pond will be to simulate this very episode where the wire will burn out!

 

Six years later……..Great Eastern does the biz!……..That`s where we come in!

Cue Bob Abell and team!……..Action!…….Poop! Poop!…….Here we go boyz!

 

In fact, we could be sailing tomorrow!

 

This is the over run brake…….The hole is for adding further weight if required

 

Bob

[Bob Abell 2Participant @bobabell2]

Ahoy there!…….Ahoy!…….We are sailing!…….Tomorrow……..Hoorah!

 

We`ll be Flying the Blue Peter of course!

And the company flag……The Trans Atlantic Cable Company

And the Red Duster…….The original Red Ensign

Plus three more……The Union Jack of course…..The Tricolour of France and Old Glory herself…..The Star Spangled Banner

Thank you Dermis, for sorting out the flags

Capt Bob casting orf!

[Bob Abell 2Participant @bobabell2]

Sorry chaps

 

Weather forecast is no good today in mid Atlantic Etherow!

No sailings today

 

Capt Bob

[DermisParticipant @dermis]

Wow, she’s really looking the part now!

 

One note..GE laid the first French TA cable in 1869. So, she would not have flown the French tricolour until then.

 

http://www.atlantic-cable.com/Article/1869French/index.htm

[Bob Abell 2Participant @bobabell2]

Thanks Dermis

 

Let`s assume we are laying the french cable then?

( Your email timed at 9.25 won`t open )

 

Couldn`t sail anyway……First officer Teal is laid up……..and it`s raining now!

 

Bob

[Mark Beard 1Participant @markbeard1]

“Heros of the Telegraph” by John Munro describes the use of the mirror galvanometer, which allowed very tiny signals to be detected, and greatly improved the speed of transmission. Morse code was encoded by sending alternating polarity pulses, each polarity representing dots and dashes.

 

“When there is no current on the instrument, the spot of light remains stationary at the zero position on the screen; but the instant a current traverses the long wire of the coil, the suspended magnets twist themselves horizontally out of their former position, the mirror is of course inclined with them, and the beam of light is deflected along the screen to one side or the other, according to the nature of the current. If a POSITIVE current–that is to say, a current from the copper pole of the battery–gives a deflection to the RIGHT of zero, a NEGATIVE current, or a current from the zinc pole of the battery, will give a deflection to the left of zero, and VICE VERSA.”

The whole text may be found at http://onlinebooks.library.upenn.edu/webbin/gutbook/lookup?num=979.

 

Mark the Spark

[Bob Abell 2Participant @bobabell2]

Thanks Mark

This is the schematic diagram of the device…

Bob

[Bob Abell 2Participant @bobabell2]

Latest requirement….

 

Once GE has reached the far shore, easy access to the drum end of the cable would be nice.

 

This entails two buzz rings on the drum flange with brushes taking the circuit to two terminals on deck for quick crocodile connection

 

What an exciting challenge?

 

Bob

[Mark Beard 1Participant @markbeard1]

I remember using a mirror galvanometer with a Wheatstone Bridge back in GCE Physics – I think I’m showing my age now!

 

[Bob Abell 2Participant @bobabell2]

Showing your age, Mark?

 

You`re just a young whippersnapper!……….And enjoy life while yer can!

 

It`s finally stopped raining here, but it`s given me time to make the buzz rings……

 

I`ve got a cunning plan!

 

Bob

 

PS……..Is it safe to send 12volts down the 100m line in the coiled up state?

  

Good question?

 

Edited By Bob Abell on 07/06/2011 14:45:11

[Bob Abell 2Participant @bobabell2]

 

Got the live drum request sorted…..

 

Using brass washers each side of drum

 

Drum wires goes to each inside washer

 

Terminal wires go to each outer brass washer

 

So when GE reaches the shore, we simply connect the galvanometer station to two terminals on the deck, with crocodile clips!

 

Like it?…..Yep!

[Bob Abell 2Participant @bobabell2]

This is the starboard outer live washer……The wire goes to a terminal on the deck

 

The drum has a similar live washer, the washers are spring loaded against each other….thus completing the circuit.

 

There are two more similar washers on the port side

 

Bob

[Bob Abell 2Participant @bobabell2]

Hello Mark

 

The bulb has arrived……..Thanks a lot!………..You have been very helpful during the project and is much appreciated

 

Just the job!…….Bob

[Bob Abell 2Participant @bobabell2]

Mark or Jonathan

 

Can I safely apply 12 volts to the coil….When it`s fully wound up?

 

What`s the correct term for the live washer system being used?

 

Slip rings?……Buzz rings?…….or what?

 

Bob

[Mark Beard 1Participant @markbeard1]

The only restriction on applying power to a coiled up drum of cable is that cooling is impaired. If you’re using that bulb or a small buzzer, there should be no problem at all.

 

I’d call them slip rings, but these are only words – so long as we know what you’re talking about that’s fine.

[Bob Abell 2Participant @bobabell2]

Thanks for that, Mark

 

I once did some electric welding with the extension lead partly uncoiled and it exploded!

The same thing applies with caravan extension leads, they need to be encoiled too

 

 

Finished the slip ring assemblies at last…..

All the pieces are squeezed together with the spring along the axle, for good electrical conductivity. The rod on the left is for releasing the spring, for drum insertion

The axle is not in contact with the slip rings

 

Next job is the deck terminals

 

Bob

 

 

 

Edited By Bob Abell on 09/06/2011 12:15:31

[DuckyParticipant @ducky]

Looking good Bob.

How about the good old 3 pin plug pins, as used on the Becker Rudder on previous occasions, got plenty of them if you decide to go that way!

 

[Bob Abell 2Participant @bobabell2]

Hello Duckie

 

Don`t need tellin`!……I`ve used the plug pins for the inner drum connections…….Those brass plug bits are always useful

 

Have we had some rain this week?…….With thunder and lightning too!

Perhaps next week now…..Got the finish the job first……and give you chance for your cold to get better

 

Bob

[Mark Beard 1Participant @markbeard1]

Well that is looking properly engineered. And I guess the sprung compression on the assembly will provide a little friction and act as an anti-overrun device also?

[Bob Abell 2Participant @bobabell2]

Hello Mark

 

I thought that too, but as a matter of fact, there is very little friction to be made use off, brass on brass is no friction really…..so we still need the over run brake. We`ll find out shortly anyway!

 

Bob

[Bob Abell 2Participant @bobabell2]

Could this be the final piece of the jigsaw?

The Terminals!

Port side is the red terminal……Obvious!

 

Now for the action……..Shortly

Bob

[Mark Beard 1Participant @markbeard1]

Excellent!

 

But not ‘shortly’ please, you don’t need any shorts in your circuit.

[Bob Abell 2Participant @bobabell2]

Hello Mark

 

Have connected up the cable to all connections and the circuit is there, but the wires are so fine!………Too fine for my liking, it`s just like bumfluff!……….What else is available?

 

The current pond selected is only 60m, so we can live with a shorter wire now

 

Bob

[Mark Beard 1Participant @markbeard1]

Oh, is it the same as the sample I sent you? If you send me the cable I can terminate it with stouter wire to make hooking up easier.

 

If you want an alternative, what is the maximum diameter you can accommodate through your paying-out gear?

 

Mark

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