[GreenKeys] TU for Computer

[Duncan Brown]

Paul,

I agree!!

Duncan Brown, K2OEQ
USASA    31J30

Antique Wireless Assoc. Museum,
   Asst. Curator, Commercial Equipment
(also chief TTY op & repairman)

www.antiquewireless.org


On 1/11/2019 04:22, Paul Heller wrote:
> 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 
> <mailto: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 <mailto: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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