[RTTY] Advise requested for RTTY Hardware

[Joe Subich, W4TV]

> No, that is not the "only" way.  You can use fldigi in 
> normal AFSK mode, and use K4DSP's FSK Regenerator:

That's true. Although the K4DSP FSK Regenerator will run 
on any AFSK software (and any soundcard) without the special 
p-FSK output, p-fsk is the only "supported" method for 
generating "true" FSK in fldigi. 

In addition, the envelope detector/switch approach works 
with audio generating only CW software to allow it to 
work properly with a real CW receiver. 

73, 

   ... Joe, W4TV 
 


> -----Original Message-----
> From: Kok Chen [mailto:chen at mac.com] 
> Sent: Sunday, August 16, 2009 4:28 PM
> To: RTTY Reflector
> Cc: W4TV Joe Subich
> Subject: Re: [RTTY] Advise requested for RTTY Hardware
> 
> 
> 
> On Aug 16, 2009, at 11:37 AM, Joe Subich, W4TV wrote:
> 
> > The only way to do FSK (as opposed to AFSK) with fldigi is using an 
> > envelope detector/driver as is done in USB Interface III (or as 
> > documented in the fldigi help files).
> 
> 
> No, that is not the "only" way.  You can use fldigi in normal AFSK  
> mode, and use K4DSP's FSK Regenerator:
> 
> http://k4dsp.homeip.net/~doug/regenerator/
> 
> It is however, not an appliance operator's box.  Some assembly and  
> competency with a soldering iron is required (or use a solderless  
> breadboard, as I had done when I was testing it :-).
> 
> You can indeed use Doug's regenerator with any AFSK software on any  
> operating system.  *Anything* that puts out an AFSK tone pair,  
> including all the old TNCs (in AFSK mode) will work.  With Doug's  
> regenerator, there is no need for a special 1 kHz secondary keyed  
> tone.  Just use the standard 2125/2295 AFSK tone pair on a single  
> audio channel.
> 
> Simple as it is, the AVR firmware in Doug's circuit is not just an  
> envelope detector, but the firmware includes a full fledged AFSK  
> demodulator.  It does require a signal with good SNR, but a computer  
> sound card output is more than clean enough for it.  It demodulates  
> and slices the AFSK signal into an FSK signal (and while doing that,  
> it also generates PTT).  It will also generate an independent CW  
> keying signal for various Windows and Mac OS software that generates  
> CW for J2A modulation by the rig.
> 
> 73,
> Chen, W7AY
>