[GreenKeys] Torn tape continuous transmissions

[Nick England]

The messages were sequentially numbered on each outgoing channel. The
header contained station and channel ID characters plus the message number.
The receiving station checked the numbers to detect missing or garbled
messages and request retransmission if needed. This was particularly
valuable for RTTY channels.

Some more torn tape relay info is here
https://www.navy-radio.com/tty-relay.htm


Nick England K4NYW
Chapel Hill NC
www.navy-radio.com

On Thu, Jul 23, 2026 at 9:10 PM Harold Hallikainen <harold at w6iwi.org> wrote:

> It is amazingly clever! That FIFO with the moving reader head is pretty
> unique!
>
> All those stepper switches to put a message number on the tape are
> interesting and complicated!
>
> I just thought they'd put a header on the tape during its original
> perforation. That header would be the destination, probably as a numeric
> sequence that would indicate the routing at each relay station.
>
> Years ago, I remember seeing the printer and reperf at my college
> newspaper. This used 6 bit TeleTypesetter code. At the start of each story
> on the printer was a line of overprinted garbage. But, on the tape, it
> showed up as a dot matrix human readable story number. When the editor
> found a story on the printer that he/she wanted to use, they'd zip back
> through the tape looking for the story number as readable holes in the
> tape. I always thought (and still do) that was very clever. I could see
> something like this in torn tape relay where the routing of the message
> would just be a series of numbers punched as a dot matrix bitmap.
>
> On the ping pong transmit, it seems like there would have to be an opertor
> there loading the tapes. If each new tape could be spliced to the end of
> the oldest one, an opertor would only need to be there to splice on the
> new message.
>
> All amazing stuff!
>
> Harold
> https://w6iwi.org
>
> On Thu, July 23, 2026 5:54 pm, Nick England wrote:
> > Actual torn tape relays used two TDs per outgoing line. They ran in
> > ping-pong fashion so you could load one while the other was transmitting.
> > Here’s mine in operation.
> > https://m.youtube.com/watch?v=FRdK8ZvXNcI&ra=m
> >
> >
> > The sequentially numbered message header is inserted via stepper relay in
> >  this model. Earlier versions used an additional TD with a sequential
> > header tape.
> >
> > At the receiving end, a reperf/TD tape FIFO set could be used.
> > Here’s mine
> > https://m.youtube.com/watch?v=XD97YVIaPlA&ra=m
> >
> >
> >
> > I love torn tape relay!!
> >
> >
> >
> > Nick England K4NYW
> > Chapel Hill NC
> > www.navy-radio.com
> >
> > On Thu, Jul 23, 2026 at 7:49 PM Harold Hallikainen via GreenKeys <
> > greenkeys at mailman.qth.net> wrote:
> >
> >>
> >> …,,,,,,,Instead, the line could continuously handle "tape speed." And,
> >> to me, torn tape relay is an early form of packet switching.
> >>
> >> A question on torn tape relay, when a new tape segment was passed to be
> >>  transmitted, was it spliced to the tape currently being transmitted so
> >> the line would never sit idle, and no operator needed to load the next
> >> tape? This, of course, is a FIFO buffer that handles bursty traffic
> >> input and provides continous output.
> >>
> >> Harold
> >> https://w6iwi.org
> >>
> >>
> >>
> >>
> >
>
>
> --
> https://w6iwi.org
>
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