I have a question about the pre-internet days of news transmission. I worked in radio from the late 80's to the late 90's and I always wondered how a radio stations teleprinter received its signal to print its information. I'm sure that, by this time, it was done through satellite, but what about in the pre-satellite days? Were teletype signals sent through microwave towers (like long-distance telephone traffic at that time) or was it through telegraph lines like those stranded upon poles along railroad tracks?
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Newswires
- Thread starter js6592
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Prior to satellite, AP and Reuters used one way data phone lines to send the data to ribbon printers. Later when converting to dot matrix printers, those were fed by a satellite receiver with a printer output.
And in much of the world, it was fed by a radio data signal. Newspapers and radio and TV outlets had an antenna connected to a communications receiver which fed a translator box which gave the instructions to the teletype.
I assume those phone lines were, in part, provided by the AT&T Long Lines microwave network. Or Possibly the Western Union equivalent.
But I don't have any specific evidence to say that AP, UPI, Reuters etc were customers of either of those services.
But I don't have any specific evidence to say that AP, UPI, Reuters etc were customers of either of those services.
Sure, much of the 'long distance' phone traffic traveled over microwave between points back in the day. You can still see some of those old signature AT&T sites near major highways. Mainly the self supporting angle iron towers with flat tops and a concrete building below. Some still have the old 'horn of plenty' microwave antennas still attached. It's safe to assume a small portion of that traffic through those sites included newswire data.
Years ago many news services were transmitted over shortwave by what was known as radio teletype, or RTTY.
50 years or so ago, my Dad, who was a ham radio operator, built a demodulator unit (vacuum tube design) for receiving RTTY on shortwave. An oscilloscope was used to properly tune the frequency-shift-keying (FSK) signal, and the demodulator sent electrical pulses to an old Kleinschmidt teletype machine. All sorts of services such as press agencies, weather forecasts, and various other text communications could be printed out.
RTTY transmissions had several different “words per minute” (WPM) speeds, and the Kleinschmidt teletype machines had gears that could be changed out for various WPM rates. There were also different frequency shifts used for FSK transmissions which the demodulator could switch between.
So the setup was a shortwave receiver feeding the demodulator+oscilloscope, feeding the teletype printer. Archaic by today’s standards but quite amazing at the time! Lots of fun as services all over the world could be accessed.
Dad also built a slow-scan TV receiver for shortwave, but that is another story…
Into the early 80's Associated Press tty service (using old model 15 teleprinters) were delivered via DC pair non equalized phone lines provided by whoever the local phone co was. AP had their own techs (in Ohio they were headquarted in Columbus) to service the equipment and work with telco problems. The service tech for Ohio for several years was Paul Kranjack.
The AP service (I think) was fairly slow speed FSK. The demodulators were boxes about the size of shoeboxes made by Lenkurt. They had 2 lamps on the front - a yellow activity lamp which flashed with incoming "data" and a red failure lamp for when there wwas no carrier present. When the service went down, you called AP, not the phone company.
At my college station in the late 70's we had a weather teletype. It was a TTY model 28 RO. It was also fed via phone line from the NWS office in Canton, Ohio. The service was free, byt we owned the printer and were responsible for its maintenance.
When AP went with Satellite delivery (in Ohio the changevoer was in 1983) the entire old system including the printers was retired. The new system used a small (18 inch or so) dish and a radio demod box the size of an old AT style desktop. The new printer was a small dot matrix unit. If you still had one of the big old black model 15's (with its own stand) you could keep it, but they collected all the demodulators.
The AP service contract included paper and ribbons in the contract price. Every few weeks a truck showed up with big boxes of paper rolls. The paper was yellowish rag paper. The printer ribbons were all black but would fit on an ordinary manual tupewriter, so people tended to boost them, specially in college.
The AP service (I think) was fairly slow speed FSK. The demodulators were boxes about the size of shoeboxes made by Lenkurt. They had 2 lamps on the front - a yellow activity lamp which flashed with incoming "data" and a red failure lamp for when there wwas no carrier present. When the service went down, you called AP, not the phone company.
At my college station in the late 70's we had a weather teletype. It was a TTY model 28 RO. It was also fed via phone line from the NWS office in Canton, Ohio. The service was free, byt we owned the printer and were responsible for its maintenance.
When AP went with Satellite delivery (in Ohio the changevoer was in 1983) the entire old system including the printers was retired. The new system used a small (18 inch or so) dish and a radio demod box the size of an old AT style desktop. The new printer was a small dot matrix unit. If you still had one of the big old black model 15's (with its own stand) you could keep it, but they collected all the demodulators.
The AP service contract included paper and ribbons in the contract price. Every few weeks a truck showed up with big boxes of paper rolls. The paper was yellowish rag paper. The printer ribbons were all black but would fit on an ordinary manual tupewriter, so people tended to boost them, specially in college.
In the early 1960s, the AP wire service to the radio station in my home town in Georgia was a DC pair from the telco office out to the station. I don't know the equipment used by the telco to get the signal to the home town telco central office.
Somewhere along the line, late 1960s, I'd guess, the AP converted over to the Lenkurt 25 tonepack system.
I seem to recall that the Lenkurt could handle about 25 slow speed wire circuits, 66WPM and maybe one or two 100WPM circuits. The individual printers had the single channel Lenkurt box under the M15 printer. Each of these boxes had the channel filters for the service the subscriber was paying for, but since it was an audio grade circuit, all of the channels were there on the audio pair.
The Lenkurt unit at the AP offoce was a rank mount system with all the tone modulators for the service.
As an example, the AP office in Raleigh supplied both North Carolina and South Carolina subscribers. I think there were separate state radio wires. Also on the Lenkurt was the morning slow speed newspaper circuit and the evening slow speed newspaper circuit. The stock market circuit was so large that in order to get all the data to the newspapers via the slow speed circuit, it was actually split in two, with half the markets on one circuit, the other half on a second circuit.
I just don't remember what else was on the Raleigh AP datasytem - I know it had to have more channels in use.
The AP did not have many Extel printers in North Carolina and I don't remember if any of the Extels used the external Lenkurt box or used an internal tone module.
The UPI Extel at one station I worked at in North Carolina, the tone unit was built into the Extel.
Somewhere along the line, late 1960s, I'd guess, the AP converted over to the Lenkurt 25 tonepack system.
I seem to recall that the Lenkurt could handle about 25 slow speed wire circuits, 66WPM and maybe one or two 100WPM circuits. The individual printers had the single channel Lenkurt box under the M15 printer. Each of these boxes had the channel filters for the service the subscriber was paying for, but since it was an audio grade circuit, all of the channels were there on the audio pair.
The Lenkurt unit at the AP offoce was a rank mount system with all the tone modulators for the service.
As an example, the AP office in Raleigh supplied both North Carolina and South Carolina subscribers. I think there were separate state radio wires. Also on the Lenkurt was the morning slow speed newspaper circuit and the evening slow speed newspaper circuit. The stock market circuit was so large that in order to get all the data to the newspapers via the slow speed circuit, it was actually split in two, with half the markets on one circuit, the other half on a second circuit.
I just don't remember what else was on the Raleigh AP datasytem - I know it had to have more channels in use.
The AP did not have many Extel printers in North Carolina and I don't remember if any of the Extels used the external Lenkurt box or used an internal tone module.
The UPI Extel at one station I worked at in North Carolina, the tone unit was built into the Extel.
AP and UPI ran at 60 or 66 wpm. NWS ran at 75 wpm which was about as fast as a Model 15 would run. AP and UPI wires were non-eq audio circuits. The Lukert demod was stop-start and jnot FSK. Hence when the circuit dropped the machine would "run open." NWS was classified as a "telegraph" ckt and was a continuous metalic pair. Many of the Model 15 teletypes were military surplus. I could fix them if I could find the parts. Radio and NWS were 5-level (bit) Baudot. Newspaper wire was 6-level so it could handle capital leters and control codes for different fonts in the type setting machines.
For radio there was a 5-minute national summary that was sent ever hour plus one minute headlines. A 5-minute state summary was sent (as I remember) 4 times a day with one minute state headlines sent periodically. Plus there was sports news and scores. Reading line scores for baseball was an art.
I still have the AP Style book which has transmission schedules, how to write for the wire plus a great section on writing style.
BTW: I remember local Florida stores ending with "-MH-" which I was told was the telegrapher's designation for "Miami Herald" since that where the AP office was for years.
For radio there was a 5-minute national summary that was sent ever hour plus one minute headlines. A 5-minute state summary was sent (as I remember) 4 times a day with one minute state headlines sent periodically. Plus there was sports news and scores. Reading line scores for baseball was an art.
I still have the AP Style book which has transmission schedules, how to write for the wire plus a great section on writing style.
BTW: I remember local Florida stores ending with "-MH-" which I was told was the telegrapher's designation for "Miami Herald" since that where the AP office was for years.
I disagree on that characterization of the Lenkurt system. It indeed was an FSK system.
See page 15 at:
Yes, if the circuit dropped, there was no valid mark or space signal, therefore the loop would run open.
The AP was probably 66WPM in the mid-1960s, but it might have been a state-by-state conversion.
I seem to recall seeing an instruction packet sent out to AP subscribers with the two gears required to change the speed from 60 WPM to 66WPM with the intention that a technical person at the radio and TV stations could make the gear change. I think I have another research project!
The newspaper circuits used Teletypesetter coding - 6-level.
The Model 20 printers had upper and lower case, per the 6-level code, but ignored many of the control codes which were Linotype unique.
The 6-level coding can be seen at:
Good Lord... It was a long time ago. Does it really matter?
People are still using FSK for radio teletypewriter service.
Perhaps technically, it might be more AFSK, single sideband with good suppression of the opposite sideband and the carrier?
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