[GreenKeys] New RTTY Handbook TU's

[Harold Hallikainen]

I could add the scans to https://w6iwi.org/rtty/ , if desired. Do you
think a pdf of the image would remain clear? PDF seems to be pretty
universally used.

When I was in high school, I remember one of my model 15s having a polar
relay in the back. There was also a TU that used a polar relay to make the
mark/space decision. In general, I did not find much use for the polar
relay.

I guess they were used on telco loops. Is there an advantage to polar
signals versus on/off on a telco loop? I guess there might be an advantage
in that the receiver is driven to mark or space instead of just being
driven to mark with a spring pulling the armature to space. It would be
interesting to have a selector magnet with a permanent magnet where
current in one direction would pull the armature to the coil, and current
in the other direction would push it away.

Harold



> I already have those pages scanned. I save as BMP's so the schematics are
> clear. That makes them pretty big.
>
> If Someone would like to put my scans on their website including the pages
> on adjusting polar relays, I could try to get them to him.
>
> Another TU circuit in that book used a balanced circuit to operate a polar
> relay as its loop keyer. In my opinion, a much better use for the relay
> than destroying it. I have also scanned that article.
>
>
> Tom    N3CRK
>
>
> -----------------------------------------------------------
>
> Ralph Irish wrote:
>
> Years back, the "New RTTY Handbook" had a few pages dedicated to making
> a Terminal Unit and fitting the entire thing into a Polar Relay enclosure!
>  I
> don't recall much else but it was an interesting idea.
>
> The design was on a PC board and wires went from the board to the pins
> inside
> the relay device.  If there is any interest, I will dig up my copy of the
> Handbook
> and scan the few pages involved with this project.  If nothing else, it
> will be a
> perfectly good use of a Polar Relay (enclosure).  Doing this will also
> require a
> Polar Relay socket.
>
> 73,
>
> Ralph - W8ROI
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