[GreenKeys] Polar Relays

[Harold Hallikainen]

Long ago, I had a TU with a polar relay in it. As mentioned here, the
mark/space decision was made in the relay. Also had a Teletype model 15
with a polar relay in back. But the TU I ended up using a little over 50
years ago used a 6L6 to key the loop. It also had the 88 mH loading coils
in the filters.

On generating polar signals, I think I've seen schematics of a TD and/or
keyboard with SPDT switches so you could send polar.

It would also be interesting if the selector magnet had a permanent magnet
so the coil current could attract or repel the armature instead of using a
spring to return the armature.

Harold