[ScanIndiana] Re: ACARS

[Eric Sluder]

Thx for the detailed reply - much appreciated!

73 - Eric
W9WLW
  ----- Original Message ----- 
  From: David L Norris 
  To: ScanIndiana Mailing List 
  Sent: Monday, October 11, 2004 11:22 PM
  Subject: [ScanIndiana] Re: ACARS


  On Mon, 2004-10-11 at 21:51 -0500, Eric Sluder wrote:
  > Have any of you been successful in monitoring ACARS traffic on the air band?

  Sure, it is rather trivial to do.  You simply need a radio capable of
  demodulating 6KHz wide AM signals on the aircraft bands (131.55 MHz
  mainly).  Connecting to the speaker or record jack works with some
  radios but not others.  You may need to tap the radio's audio before the
  internal squelch and filtering circuits.  You may not be able to just
  connect to the speaker or record jacks.  Most radios have audio filters
  which filter out the data tones.  

  There are many programs that will decode ACARS and most use a sound
  card.  Since it is AM signal strength and noise are major factors.  Any
  noise whatsoever on the signal makes it impossible to decode.  The data
  bursts are very susceptible to interference from, sometimes inaudible,
  pops and clicks.

  I was using acarsd on Linux a few years ago.  It supports sound card
  decoding and on Windows it can communicate with the radios via Airmaster
  or Skyspy.  You leave acarsd running 24/7 on one machine (Linux or
  Windows) and it logs all traffic on the ACARS channel.  Then you can
  access the logs using one of various graphical front-end programs.  You
  can then plot the aircraft courses on world maps, generate graphs of the
  various types of aircraft passing over your area, cross-reference tail
  numbers with aircraft registration info, and so on right within the
  program.  And for many commercial (and some private) aircraft you can
  instantly bring up (or upload) a photo of the aircraft; not just a photo
  of that type of aircraft but a photo of that very aircraft itself.
  (Although taking photos of aircraft these days would probably get you
  shot on sight. ;-)

  There are screenshots of the Java graphical interface for acarsd:
    http://www.acarsd.org/screenshotc.html

  -- 
   David Norris
    http://www.webaugur.com/dave/
    ICQ - 412039

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