[RTTY] Crazy Idea for FSK

[Kok Chen]

On Feb 13, 2008, at 1:37 PM, Lee Buller wrote:

> Here is the crazy idea....a reverse terminal unit.  How about  
> decoding the tones coming out of the soundcard in AFSK and turning  
> them into to switched pulses.  Now I am not an electronics engineer  
> or even close, but that would solve the problem of FSK....just  
> demod the output of the soundcard and then use that on the FSK line  
> of any rig.  One could do this with a couple of 567(?) decode chips  
> are what ever is on the market at this time.  Heck, I think you  
> could do it with one chip.  Use an optoisolator to key the rig.  FSK!

Not crazy at all, this has been done, see for example:

http://lists.contesting.com/_rtty/2005-03/msg00035.html

Remember that you also have to add a carrier detect to key the PTT line.

K4DSP Doug has a newer solution for FSK regeneration, but I'll not  
let the cat out of the bag and let him describe it.

You can also use an ST-8000 too, by the way.

73
Chen, W7AY