[GreenKeys] New to real Teletype

[Ralph Mowery]

You can print just by hooking the wires from the print unit and the keyborad 
in series with a power supply.  The power supply can be most anything from 
around 20 volts to 150 volts.  You will need a resistor in series to limit 
the current to 60 ma.  This is around 2500 ohms at 10 or 20 watts for the 
resistor to much less at the lower voltages.  Just make sure the current is 
as close to 60 ma as you can get it.  Too much current will burn up the 
coils and not enough will not pull in the magnets.

To print off the air or internet you will need a device to convert from the 
two tones of (usually) 2125 and 2295 Hz to electrical pulses.  This is 
called a TU (terminal unit) or demodulator.  That is what the ST-6 is, but 
there are many others.  Go to RTTY.COM and look at the info there.  About 
the simplest if you want to build one is the ST-5.  For the 709 you can 
subistute some 741 or similar op amps.  They may not work as well,but will 
work if the 709 is too difficult to obtain.  If you are not able to build 
one, sometimes the TUs show up on ebay.  I don't know of any that are being 
sold new now.

YOu can often find the rtty around 14.090 and the ARRL sends out bullitens 
several times at night on several bands.


Good luck with the machine.

----- Original Message ----- 
From: "Trent Williams" <tsdptsdp at icloud.com>
To: <greenkeys at mailman.qth.net>
Sent: Sunday, October 18, 2015 6:33 PM
Subject: [GreenKeys] New to real Teletype


> Hello from KJ4KAF,
> Yesterday, I brought home a model 28 KSR.  The seller (ham operator) gave 
> me a good demonstration of the printing function as a signal was fed from 
> an ST-6. However, the keyboard function is not connected to anything it 
> seems. The keys do function and there is mechanical action when a key is 
> pressed.
>
> His signal feed line appears to bypass almost everything and connects 
> directly to the 2 solenoids (wired in parallel). The line has around 65 
> ohms of resistance.
>
> Is there a way to have the machine print what I type? Is an ST-6 what I 
> need as well?  My first goal is to receive anything I can find on the 
> bands or the Internet. At some point, I would like to at least print what 
> I am typing - will the right TU do this?
>
> This is the first teletype I have ever seen - what an incredible 
> mechanical wonder this thing is!
> Today, I just signed up to join the email list.
>
> Thanks for any help understanding this, Trent