[GreenKeys] Bell 103 demodulator?

[Dave G4UGM]

Well those tones about sound right for Bell 103, as I see from 

http://en.wikipedia.org/wiki/Bell_103_modem

"The answering station used a mark tone of 2,225 Hz and a space tone of
2,025 Hz."

So is 266.6 baud the right number? Might be worth looking in something like
spectrum lab but I can't get a decent waterfall display and I am not really
used to the tool.

Dave.

-----Original Message-----
From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of
epvgk at limpoc.com
Sent: 13 September 2014 09:42
To: W2HX
Cc: greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] Bell 103 demodulator?

On Fri, Sep 12, 2014 at 08:36:00PM -0700, W2HX wrote:
> Hello folks,
> 
> I have an audio file (wav) that I have been told represents data in 
> the following audio format:  Bell 103 data, 266.6 baud, 850 shift,
1300/2100 tones Does anyone know what software can be used to decode this? I
am posting it here in case it helps figure this out.  Thank you all.
> 
> http://www.w2hx.com/x/PRC-319/
> 
> 
> 73 Eugene W2HX

I fiddled around with it a little but no luck. The tones appear to be 220 Hz

apart, not 850, if the file's WAV header is correct and it's sampled at
16khz.            
The tones seem to be 2228 and 2008 Hz, with the higher one as mark.

Even so, I couldn't get minimodem or fldigi to decode it to anything human

readable either as ascii or baudot with any of the permutations of options I

could think of... :(            


eric
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