[GreenKeys] TU for Computer

[Paul Heller]

I know the hobby is moving (has moved?) to software defined radios, digital signal processing, digital ham modes, etc.  Even I, by digitizing ITTY and broadcasting it out on the internet, am doing some things digitally.

Yes I still prefer those “blinken lights” and the old school analog ways. However I feel I am finding myself in a smaller and smaller room, more and more alone...

Paul
W2TTY



> On Jan 11, 2019, at 4:22 AM, W7HPW Radio <W7HPW at outlook.com> wrote:
> 
> Jim,
> 
>    You got the idea
> 
> " , but I think what you
> are asking is for software that replaces the demodulator with digital
> signal processing so you can drive a TTY machine with the Baudot output."
> 
> Exactly  and the reverse, accept TTY keyboard  input and produce the tones for transmission, 
> 
> My ST-6 works fine but an upgrade to DSP coding and decoding would be very nice!
> 
> Mark
> 
> -----Original Message-----
> From: Jim Haynes [mailto:jhhaynes at earthlink.net] 
> Sent: Thursday, January 10, 2019 7:36 PM
> To: W7HPW Radio
> Cc: greenkeys at mailman.qth.net
> Subject: Re: [GreenKeys] TU for Computer
> 
> Yes and no.  Of course you are aware of all the computer software that
> turns the computer into a complete RTTY terminal, but I think what you
> are asking is for software that replaces the demodulator with digital
> signal processing so you can drive a TTY machine with the Baudot output.
> 
> The earliest DSP software was K6STI's RITTY program.  I talked him into
> providing a cleaned-up Baudot output when it was receiving, but didn't
> ask him to provide for a TTY keyboard input.  The story of that software
> is that it ran under DOS, required a certain kind of SoundBlaster
> sound card, and was rather expensive.  He pulled it off the market
> because it was being pirated, and also never ported it to anything beyond
> DOS and a more generic sound system.  I think he said it was not possible
> to do that and maintain the performance it gave.
> 
> I shouldn't say that was the earliest - there was probably some using a
> dedicated DSP engine, but K6STIs was the first to use a PC that I know
> of.  And you didn't find many Pentium computers running DOS even back
> then.
> 
> I think I was told that MMTTY has a Baudot output, but that may not be
> true and I haven't looked.
> 
> I've begged Dave W1HKJ to add a Baudot output to fldigi but apparently
> that is either not possible or is not a high priority.  Maybe if more of
> us begged for it he would do it.  It is open source, so maybe somebody
> else could do it.
> 
> You don't want just an ST-6 equivalent in software; you really want
> regenerated Baudot to go to the printer.  Because there is something
> like a 15dB disadvantage to Start-Stop TTY signals caused by the
> mechanical selector in the machine.
> 
> What some people currently consider the best software demodulator is
> 2Tone, which does not run standalone but runs under N1MM Logger.  It
> is free but closed source.  I don't know if one could figure out how to
> use the 2Tone module with his own wrapper to make it function as a
> simple demodulator.
> 
> Jim W6JVE
> 
> 
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