[GreenKeys] What brought you here?

[Harold Hallikainen]

When in high school (graduated in 1969), I had a friend that was always
looking to sell something to pay his motorcycle insurance. That's how I
got my first model 15. There was a guy in Oakland CA that had a back yard
full of Teletype stuff under a big tarp. I'd go there and buy more stuff.
On my ham station (Viking Ranger transmitter, National NC-300 receiver), I
ended up running the model 15, a 14 TD, and a 14 typing reperf. I also had
a Kleinschmidt KSR machine. I put another model 15 at a friend's house
about a mile away. We ran a single wire (surplus military field phone wire
untwisted to get two single long wires) through the trees. We ran the
current loop with that wire and a ground connection at each end. It was
then that I found I could get 60 mA with 12V, but it would not type
correctly! It was then that I learned about time constant (T=L/R). So,
high voltage and a big resistor. We had a loop supply and a current sense
relay at each end. The motors would start when either of us brought up our
loop supply. We'd then type the message, and drop the supply, turning off
both motors.

In college, I had the only dorm room with a Model 15!

Harold
http://w6iwi.org


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