Re: [Tlf-devel] Few modification for RTTY

[Ed]

On 02/11/2014 05:54 AM, Martin Kratoska wrote:


> P.S. MMTTY is capable to key the FSK, also probably Digipan (I need to
> fill the gaps in my memory) but AFAIK NO LINUX software! The very
> popular fldigi uses "pseudo FSK" which is an AF signal which is
> rectified and switching the radio FSK input via transistor switch. The
> problem is the rectifier, its filtering capacity is rather critical. BTW
> when I cooperated with Tony, VE6YP on the YPLOG we developed a CW keying
> system capable to key you TX up to 200 WPM - it was a very unique
> option. Also I collected a lot of experience with such rectifiers and
> can say, it is very tricky! Anyway, we need to beat the timing (latency)
> issues to get an useful FSK program.

Dave, W1HKJ, looked into adding FSK into fldigi. The problem at that 
time existed in the kernel, and probably still does. This is why the 
pseudo-fsk option was introduced. Martin is correct that the interface 
can be tricky.

This is the latest information on how fldigi does RTTY

 http://www.w1hkj.com/FldigiHelp-3.21/html/rtty_page.html

I also recommend looking at W7AY's web page

 http://www.w7ay.net/chen/index.html

Ed W3NR