Hi Roger,
The power available at the receiving end of 19th century transatlantic
cables was so feeble that it couldn't possibly be detected by an undulator.
William Thomson, later knighted as Lord Kelvin, invented the mirror
galvanometer in 1857 for use on the first transatlantic telegraph cable.
The syphon recorder replaced Thomson’s mirror galvanometer as the
standard receiving instrument for submarine telegraph cables about
ten years later.
Good descriptions of these early submarine telegraph instruments
are here:
http://atlantic-cable.com/Article/Instruments/index.htm
73
Frank
W3LPL
----- Original Message -----
From: "Roger Parsons via CQ-Contest" <cq-contest@contesting.com>
To: "Contest" <cq-contest@contesting.com>, donovanf@starpower.net
Sent: Tuesday, June 4, 2019 8:36:03 PM
Subject: Re: [CQ-Contest] e: Fwd: [wsjtgroup] WSJT-X 2.1.0-rc6
Clearly so! I was not aware of this and perhaps I should have been.
My experience was related to long underwater telegraph cables where cable
capacitance and losses meant that devices using negligible power were
essential. Hence the undulator, which was certainly in use for approaching 100
years. A casual internet search did not find any information on these devices,
but probably it is there somewhere.
But apart from being wrong, I am definitely right in saying that undulator tape
can be read very fast indeed!
73 RogerVE3ZI
On Tuesday, 4 June 2019, 14:32:12 GMT-4, donovanf@starpower.net
<donovanf@starpower.net> wrote:
Zack is correct and Roger's historical knowledge needs a little work.
This is an image of Morse's original 1844 paper tape on display in the
Smithsonian:
http://ids.si.edu/ids/deliveryService?id=NMAH-2006-10282
Roger, this is a good place to start. The paper tape embossing instrumentused
during Morse's Washington-Baltimore two way demonstration isshown in the
article. It was very noisy!
http://time.com/4307892/samuel-morse-telegraph-history
73FrankW3LPL
From: "Roger Parsons via CQ-Contest" <cq-contest@contesting.com>
To: "Contest" <cq-contest@contesting.com>, "w9sz zack" <w9sz.zack@gmail.com>
Sent: Tuesday, June 4, 2019 2:21:19 PM
Subject: [CQ-Contest] e: Fwd: [wsjtgroup] WSJT-X 2.1.0-rc6
Zack, W9SZ wrote:
"The original Morse telegraph (and others) worked by imprinting the dots and
dashes on a paper tape and then decoded by reading it. Imagine doing a
contest that way! Then someone figured out that it was faster to learn to
decode the messages by ear."
I have no horse in the WSJT race, but just a little historical comment:
The original telegraph using paper tape used an undulator. (This is a moving
ink nozzle that will move up and down in response to the received signal. So
there is a continuous print.) Having had to learn to read undulator tape (both
Morse and cable code) at the end of an era, I can confidently say that it was
possible to easily read either at 100 wpm. I think that audio reading (tone or
clicks) came about because of (1) the cost and maintenance levels required for
undulators at small stations and (2) undulators did not work at all well on
early radio receivers.
73 Roger
VE3ZI
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
|