[GreenKeys] ITTY Poll

Paul Heller paul0926 at comcast.net
Thu Sep 23 15:00:29 EDT 2021


I have just restarted ITTY100 streaming at the lower sampling rates.  Give it a few minutes to reboot and let me know what happens on your end.

Paul
W2TTY
i-Telex: 80003 or 468466

ITTY:  		HTTP://INTERNET-TTY.NET:8000/ITTY
ITTY100:  	HTTP://INTERNET-TTY.NET:8010/ITTY100
AUTOSTART:  HTTP://INTERNET-TTY.NET:8030/AUTOSTART
EUROPE: 	HTTP://INTERNET-TTY.NET:8040/EUROPE


> On Sep 23, 2021, at 12:46 PM, William Wuttke <wcwuttke at att.net> wrote:
> 
> Paul,
> 
> Give it a whirl. I'll tune to 100wpm.
> 
> Bill
> KE3BK
> On Thursday, September 23, 2021, 09:58:15 AM PDT, Paul Heller <paul0926 at comcast.net> wrote:
> 
> 
> ITTY is sampling the audio at 11025Hz, 16 bits per sample, mono. When I tried going lower some said they were having trouble. I could easily try it again, but that’s where it stood a few years ago and I’ve not touched it since.
> 
> 8 bit/8kHz would be an interesting test! I’m all for using less bandwith. Maybe I’ll try this on the 100WPM channel and let the users who are using it tell me how it goes. If anyone wants to be in on this test (100WPM) let me know and we will give it a whirl. If it works there, I can move the lower sampling over to the 60WPM channels.
> 
> And if you all twist my arm, we can do the test on the 60WPM channel to start with.
> 
> Paul
> W2TTY
> 
> ITTY: 		HTTP://INTERNET-TTY.NET:8000/ITTY <http://internet-tty.net:8000/ITTY>
> AUTOSTART: HTTP://INTERNET-TTY.NET:8030/AUTOSTART <http://internet-tty.net:8030/AUTOSTART>
> EUROPE: 	HTTP://INTERNET-TTY.NET:8040/EUROPE <http://internet-tty.net:8040/EUROPE>
> 
>> On Sep 23, 2021, at 10:09 AM, Harold Hallikainen <harold at w6iwi.org> wrote:
>> 
>> Methods of doing AFSK Internet broadcasts like ITTY are interesting. I
>> thought the idea of splicing together mark and space tone files was very
>> clever.
>> 
>> I wonder about the need for audio compression. I did a microcontroller
>> project that streamed live audio using ADPCM and PCM. The PCM used 16 bit
>> samples at 44.41 kHz. But, I think for RTTY, 8 bit samples at 8 kHz should
>> be fine (since that's what circuit switched telephone uses). In my
>> application, on receiving the HTTP request, I sent the WAV header with a
>> very large file size, then just started sending the samples.
>> 
>> As mentioned, I do think the splicing of tone files is very clever!
>> Another method that would be interesting is direct digital synthesis.
>> Depending on the desired frequency, each successive sample would be some
>> number of steps through a sine table from the previous sample.
>> 
>> Anyway, interesting stuff!
>> 
>> Harold
>> 
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