[GreenKeys] Bell 103 demodulator?

[W2HX]

Oops. Wrong. The actual text is: “THIS IS A TEST FOR THE FOLKS AT GILBERT MEET”

Also, the unit is UPPER case only. So I don’t know if that might suggest 6 bit?

73 Eugene W2HX

From: GreenKeys [mailto:greenkeys-bounces at mailman.qth.net] On Behalf Of W2HX
Sent: Sunday, September 14, 2014 5:51 PM
To: Suhayl Khan; greenkeys at mailman.qth.net
Subject: Re: [GreenKeys] Bell 103 demodulator?

Wow. This is VERY impressive. That is the beauty of this list. You ask for help and you get it. Thank you, Suhayl.  The text of the message is "This is a test to send msg A"

Looking at what you did, I can see this message somehow embedded within the data. To spare the other folks on the list, I’ll follow up with you directly. Thanks for quite an impressive effort!



73 Eugene W2HX

From: Suhayl Khan [mailto:suhaylkhan at gmail.com]
Sent: Sunday, September 14, 2014 4:37 PM
To: greenkeys at mailman.qth.net<mailto:greenkeys at mailman.qth.net>; W2HX
Subject: Re: [GreenKeys] Bell 103 demodulator?

Hi Eugene,

I built the following circuit this morning:

http://imageupper.com/i/?S0200010060011H141072536787361

Following the instructions found here: http://colinfahey.com/phone_interface/phone_interface.html

I then connected a Bell 103 compliant modem (0-300 baud) to a bit rate converter configured for 266-N-7-1, and a PC to the other end of the converter.

Next I dialed into the modem [set to Originate] and played the wav file to the modem using the circuit I constructed above. Below are some of the results [I needed to increase the volume of the wav file multiple times to get the Carrier Detect light to come on the modem so this may have introduced some error]:

{lbCdEFJk@[]\N}tHaS at iS@A at teSt@for at tHe@fglSS at At@GqtBurt at MeetfjCCCfHoHfRrxmtwBl~}N\MK at JcFEdCb\{

{lbCdEFJk at KM\N}tHqS at iS@Q at teSt@for at tHu@folKS at Qt@GilRurt at MuetfjCCCfHoHvRrxmtwRl~}N\MK at JkFEdCbl{

{lbCdEFJk@[M\N}tHaS at iS@A at teSt@for at tHe@fol[S at At@GqlBurt at MuetfjCCCfHoHvRrxmtwRl~}N\MK at JcBEdCb\{

I am curious to know what the original text is...?

Are you able to record it again but louder (e.g. mic gain set higher, mic closer to speaker...) ?

Thank you

Regards,

Suhayl Khan


On Fri, Sep 12, 2014 at 11:36 PM, W2HX <w2hx at w2hx.com<mailto:w2hx at w2hx.com>> 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


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