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Does anyone know how to decode MDC from an audio recording?

Posted: Thu Jan 05, 2012 3:46 pm
by motojoe1
I have a recording of some radio traffic. You can hear the MDC trail. I would like to decode it and find all of the ID or maybe part of it if possible. Does anyone have any Ideas?

Re: Does anyone know how to decode MDC from an audio recordi

Posted: Thu Jan 05, 2012 3:49 pm
by escomm
http://www.antistatic.org/winmdcd/

Not sure if it can decode from a recording already taken, worth looking into nonetheless

Re: Does anyone know how to decode MDC from an audio recordi

Posted: Thu Jan 05, 2012 8:34 pm
by N6LAU
Do you have a radio that decodes MDC? If so try using a separate radio to re-transmit (on an appropriate frequency of course) the section of the recording that contains the MDC ID while using the MDC decode capable radio to receive this re-transmitted message and it may very well decode it. In my experience the reliability of MDC decode is pretty good, in fact a friend of mine has an MDC ID stored on some sort of audio device and in instances where he's played it on the air my radio has decoded it just fine.

Re: Does anyone know how to decode MDC from an audio recordi

Posted: Thu Jan 05, 2012 8:55 pm
by jland138
While WinMDCD will usually work, a Cimarron is pretty bullet proof and will decode MDC as well as some other formats.
See: http://www.cimtechcorp.com/products/dis ... lus-series

They can be fed audio from any number of sources: recorded or live from a radio.

Re: Does anyone know how to decode MDC from an audio recordi

Posted: Tue Jan 24, 2012 7:03 pm
by chartofmaryland
Pray that the source audio was from a native radio, i.e. consolette or base station receiver path and not through a digitized console audio circuit.

If so you are likely out of luck. WinMDC works great with native recorded audio, but does not work with audio captured from a console that digitizes the audio before recording where it is send around an audio bus before heading to the recorder.

The Cimarron is the best way where you can setup a unit with a digital display for instant capture as well as the serial or printer port to send a string to hyperterminal for printing and timestamping.

I use the Cimarron solution with the serial dumping to the screen for timestamping and logging.

Of course an MC2500 listening to the sound card of the PC running the logging recorder works fine as well, digitized audio or not . . . . . This may be the only awesome thing I have seen from CML yet, and it works everytime.

CoM

Re: Does anyone know how to decode MDC from an audio recordi

Posted: Wed Jan 25, 2012 4:34 am
by Jim202
The other thing you should be aware of is that most of the public safety traffic should be encrypted. Plus as many people have pointed out it is not legal to monitor the MDC traffic from them.

Go for it and see what you come up with. The worst that can happen is someone finds out your decoding the traffic and complains to the wrong person.

Jim