[GreenKeys] Tuning Signals

[Bob Camp]

Hi

By far the best place to find RTTY signals these days is the 20 meter 
ham band. Tune down from 14.100 MHz and before you get to 14.080 you 
should find several 170Hz shift 60 or 100 wpm 5 level signals. Most of 
what you find will be 60 wpm.

One way to figure out if you are on the right frequency is to use a 
spectrum analysis program on a PC. Of course if you have an audio 
spectrum analyzer handy that works as well.

A quick way to check the TU is to tune to a tone from your calibrator. 
As you tune through the "magic" frequency the loop will go from marking 
to spacing. When the loop changes state this way the effect is pretty 
noticeable if the Teletype is powered up. After a while you get to 
recognize the correct tones by ear.

If the TU has an AFSK output (some do, some don't) then hook up a pair 
of headphones to the AFSK output. That will give you a very good idea 
of what the correct tone sounds like.

If you can get the setup to print junk when audio is applied to the TU 
then the loop supply and Teletype probably are set up ok. You may or 
may not be tuned to the correct sideband. You may also be tuned to one 
half the correct audio tone frequency. The wrong sideband will be 
obvious when the transmitting station goes to a continuous tone and 
your machine sits there and chatters. The half frequency thing is a bit 
harder to spot. You actually can copy signals fine when the audio tone 
is at 1/2 the correct value ...

Hope that helps a little ...

	Take Care!

		Bob Camp
		KB8TQ