I never thought about this until the matter came up in the HQ-145 thread,
but what was the process of sending messages over the telegraph lines?

Suppose I was in a small town in Oregon and wanted to send a message to a
small town in Nebraska? Is the message "broadcast", or does it go to a
clearinghouse? Can anyone on the "wire" listen in? Are there relays?

I have been a ham for almost 50 years and I have no clue. There must be
some OT who are just waiting to tell me, or know a good website.

Thanks and 73, Colin K7FM

"COLIN LAMB" wrote in message
...
I never thought about this until the matter came up in the
HQ-145 thread, but what was the process of sending messages
over the telegraph lines?

Suppose I was in a small town in Oregon and wanted to send
a message to a small town in Nebraska? Is the message
"broadcast", or does it go to a clearinghouse? Can anyone
on the "wire" listen in? Are there relays?

I have been a ham for almost 50 years and I have no clue.
There must be some OT who are just waiting to tell me, or
know a good website.

Thanks and 73, Colin K7FM
I think it depended on how complex the telegraph system
was. There are some early telegraph handbooks available at
Google Books. Most of the stuff that has been scanned and
can be downloaded complete (rather than just sample pages)
was published before 1900 to avoid copyright problems and
some is not very well scanned, but its available.
Briefly, there was a clearing house or message center on
larger systems (like Western Union) and most simpler
telegraph circuits were "party lines" will all instruments
connected in series. That's the reason telegraph keys have
circuit closers on them. Any transmission from any station
was heard at all of them. If an operator sent a message and
forgot to close the circuit the whole thing was down until
it was closed again. There was an alternative system with no
steady DC in the lines but I don't think that was used much
in the US. Seach around the telegraphy books for more.


--
---
Richard Knoppow
Los Angeles, CA, USA

In article ,
"COLIN LAMB" wrote:

I never thought about this until the matter came up in the HQ-145 thread,
but what was the process of sending messages over the telegraph lines?

Suppose I was in a small town in Oregon and wanted to send a message to a
small town in Nebraska? Is the message "broadcast", or does it go to a
clearinghouse? Can anyone on the "wire" listen in? Are there relays?

The signalling is "point to point", and there would have to be relays
to cut the effective line capacitance into manageable chunks in order
to get a reasonable transmission speed.

The military method was "outstations" to "signal office", then "office
to office" and finally to the recipient. Paper copies of the traffic
would exist at each office, and be destroyed once the message had "cleared"
(I.e: been transmitted to the next office in the chain and been
acknowledged as having been received correctly.)

They also used multiple sets on a single pair for long runs, and yes:
all the intermediate stations could hear the traffic - otherwise they
wouldn't know when there was a gap in the traffic into which they could
insert the offer of a message to another station.

A lot of civil traffic would be in code anyway - not to make it unreadable
by the telegraph staff, but simply to cut transmission costs by having 5
character groups to represent standard words/phrases/paragraphs of contracts,
etc.

I have been a ham for almost 50 years and I have no clue. There must be
some OT who are just waiting to tell me, or know a good website.

I've got some books on (the military side (British)) telegraph line
construction and operating procedure, but not the civil side.

Chris.

--
"People in general are not fundamentally stupid."
"Cite?"

Robin Munn & Simon Cozens in the scary devil monastery

"Chris Suslowicz" wrote in
message ...
In article
,
"COLIN LAMB" wrote:

I never thought about this until the matter came up in the
HQ-145 thread,
but what was the process of sending messages over the
telegraph lines?

Suppose I was in a small town in Oregon and wanted to send
a message to a
small town in Nebraska? Is the message "broadcast", or
does it go to a
clearinghouse? Can anyone on the "wire" listen in? Are
there relays?

The signalling is "point to point", and there would have
to be relays
to cut the effective line capacitance into manageable
chunks in order
to get a reasonable transmission speed.

The military method was "outstations" to "signal office",
then "office
to office" and finally to the recipient. Paper copies of
the traffic
would exist at each office, and be destroyed once the
message had "cleared"
(I.e: been transmitted to the next office in the chain and
been
acknowledged as having been received correctly.)

They also used multiple sets on a single pair for long
runs, and yes:
all the intermediate stations could hear the traffic -
otherwise they
wouldn't know when there was a gap in the traffic into
which they could
insert the offer of a message to another station.

A lot of civil traffic would be in code anyway - not to
make it unreadable
by the telegraph staff, but simply to cut transmission
costs by having 5
character groups to represent standard
words/phrases/paragraphs of contracts,
etc.

I have been a ham for almost 50 years and I have no clue.
There must be
some OT who are just waiting to tell me, or know a good
website.

I've got some books on (the military side (British))
telegraph line
construction and operating procedure, but not the civil
side.

Chris.

I don't think capacitance was so much the problem as
just plain resistance. Telegraph systems used repeaters at
periodic locations. There were several variations of
repeaters, some simplex and some duplex, but all were
arrangements of sensitive relays. There were also two
variations of sounders, local and line, varying mainly in
coil resistance. Typical local sounders were about 4 ohms,
line sounders could be anything from about 20 ohms to maybe
150 ohms. I have a maintenance sounder from Western Union
which is 400 ohms.
Line loading came fairly late when high speed and
multiplex telegraph systems began to be common. As with
telephone service periodic loading increased bandwidth (and
hence speed) at the expense of greater overall loss.
There are several sites on the web dedicated to old
telegraph equipment and a number of technical handbooks
available in PDF form from Google Books (free downloads but
some are not scanned very well).


--
---
Richard Knoppow
Los Angeles, CA, USA

COLIN LAMB wrote:
I never thought about this until the matter came up in the HQ-145 thread,
but what was the process of sending messages over the telegraph lines?

Suppose I was in a small town in Oregon and wanted to send a message to a
small town in Nebraska? Is the message "broadcast", or does it go to a
clearinghouse? Can anyone on the "wire" listen in? Are there relays?

I have been a ham for almost 50 years and I have no clue. There must be
some OT who are just waiting to tell me, or know a good website.

Go to your local library immediately and get a copy of _The Victorian
Internet_ by Tom Standage. You will love it.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 5/27/08 12:28 PM, in article , "Scott
Dorsey" wrote:

COLIN LAMB wrote:
I never thought about this until the matter came up in the HQ-145 thread,
but what was the process of sending messages over the telegraph lines?

Suppose I was in a small town in Oregon and wanted to send a message to a
small town in Nebraska? Is the message "broadcast", or does it go to a
clearinghouse? Can anyone on the "wire" listen in? Are there relays?

My small town in Oregon was Eugene, and I worked for what was then Pacific
Tel and Tel, in the Toll Testroom. We cared for all the long distance
hardware and circuits.

in the mid 50s we were encouraged to use the telegraph "order wires" for
inter-city maintenance communications, as the voice circuits were revenue
producing and they were in short supply. From Eugene I could instantly
"talk" with any or all major towns between Seattle and LA. The circuit was
a party line, where all offices heard everything and could break-in. Within
a couple years, it was replaced by a voice orderwire, with loudspeakers in
each of the offices so the people could hear the shout-down calls.




I have been a ham for almost 50 years and I have no clue. There must be
some OT who are just waiting to tell me, or know a good website.

Go to your local library immediately and get a copy of _The Victorian
Internet_ by Tom Standage. You will love it.
--scott

In article ,
COLIN LAMB wrote:
I never thought about this until the matter came up in the HQ-145 thread,
but what was the process of sending messages over the telegraph lines?

Suppose I was in a small town in Oregon and wanted to send a message to a
small town in Nebraska? Is the message "broadcast", or does it go to a
clearinghouse? Can anyone on the "wire" listen in? Are there relays?

I have been a ham for almost 50 years and I have no clue. There must be
some OT who are just waiting to tell me, or know a good website.

Authoritative answer: "It depends." grin

A single telegraph line could have multiple stations on it, with 'common'
wiring -- anything from one station on the line was echoed at _all_
the other stations -- more-or-less broadcast.

A given 'line' spanned a relatively limited distance, so 'long-haul' messages
went through relay/distribution centers between origin and final destination.
These were 'store-and-forward' facilities, rather than 'repeaters'. i.e.,
the operator on one line received the message, copying to paper, and passed
to the operator on the other line for re-transmission. Late versions of
the system replaced the 'relay' operators with electromechanical devices.
(And *NOW* you know where the name for those solenoid switches comes from

By the time the telegraph network was widespread, the "long distance" lines
were (_almost_ exclusively) only 2 stations -- enough traffic flowing end-to-
end (and beyond) that there was no net benefit to additional drops on the
line.

The 'edges' of the network -- mostly small-time rural America -- were another
story. 40 miles was a full days ride on horseback. If you were 10 miles out
of town, getting to/from town was a _half-day_. Outposts of civilization,
thus tended to be as close as 15-25 miles --- in the mountains, even closer.
Several stations, "party-lined", on a single 'line' were common. I'm not
aware of any commercial line where the station count was out of the single
digits, but I'm no expert on the matter. grin Mine telegraphs could have
*lots* of stations on the same 'paralleled' line, as various levels were
worked out, and additional horizontal bores were run.


Where you had several stations on a single line, there was a code for each
station on that line -- a multiple-duties operator could ignore an 'alert'
that was -not- prefixed with his code. If it was addressed to him, he'd
key a 'go ahead' when he was ready to receive.

The most common wiring set-up was straight series -- in each station, the
key and sounder were in series, and the stations were in series with each
other. This only needed one overhead wire, with an 'earth' ground return.
One disadvantage was that each key required a shorting switch when not in
use. Failure to short the key resulted in an 'open' circuit, with no
messaging possible until the key was closed. Same problem if any of the
sounders failed 'open'.

This was, obviously, a voltage-driven configuration -- more stations 'on line'
required higher driving voltage to ensure that the voltage drop across each
sounder was sufficient for operation.

There was another set-up used, primarily for shorter distances, and where
stations were only intermittently installed/manned -- seasonal stations,
or 'in-mine' wiring, for example. This was multiple wires 'in parallel',
with a simple T-tap wherever a station was needed. First wire was the
'battery' supply, and was tapped to feed one side of the key. Other side
of the key went back to the second wire. The sounder was wired between
the 2nd wire and 'ground' (sometimes a 3rd wire, sometimes 'earth').

Had the advantage of -not- requiring a shorting switch on the key, better
for the 'occasional' operator. AND a failed sounder did not disable the
other stations.

Had the disadvantage of requiring 2-3 times the wire of the series setup.

This configuration is current-driven -- a constant voltage requirement -- but
the current running through each key (when closed) has to drive all the
sounders.