[Scan-DC] Something different -- ACARS (131.55 MHz)

[Robert Fisher]

There's other fun stuff too...I remember tuning into some HF freq to decode weather fax transmissions (sat images, weather maps, etc).  Not as fast as the Internet, that's for certain....

For those with macs, there's a program called 'Multimode' that is like a Swiss army knife of radio...it will decode ACARS, WEFAX, etc.  

Sent from my iPhone

On Mar 26, 2012, at 20:30, "Andrew Clegg" <andrew_w_clegg at hotmail.com> wrote:

> For a change of pace, this weekend I experimented with decoding "Aircraft 
> Communications Addressing and Reporting System" (ACARS) messages from 
> airplanes. I know a lot of people on this list know all about ACARS 
> decoding, but this was one of my first forays, and it was quite interesting. 
> It's also very simple -- all you need is an analog scanner that can tune the 
> regular air band, an audio cable, and a computer. The software I used, 
> called acarsd, is free (http://www.acarsd.org/).
> 
> acarsd decodes the digital bursts, and displays the decoded data on your 
> screen. The data can include simple check-ins, maintenance messages, 
> operations requests, weather, and a bunch of other things. The data include 
> the tail number of the aircraft, and the airline and flight number if it's a 
> commercial flight. acarsd displays this info, and keeps a persistent 
> database of all the aircraft you've heard (by tail number). It will even 
> display a photo of the specific plane you've caught, if it has a picture on 
> file. (I put a screen grab at http://www.w4je.com/acarsd.png)
> 
> The fun I had was tracking how far away some of the planes were. Once acarsd 
> decodes the airline and flight number, I could look up the flight on 
> flightaware and see exactly where it was. I was surprised that I was hearing 
> flights as far away as southwestern NC, southern NY, and over the Eastern 
> Shore. The planes were at cruising altitude, so their radio line-of-sight 
> distance is hundreds of km, but still, it's cool to be able to decode 
> signals from that far away. I was out at my house in Shenandoah County in a 
> fairly benign RF environment, using an outdoor discone with a pre-amp at the 
> feed point. With that setup, I was catching an ACARS burst every 15 seconds 
> or so during heavy flight times like Sunday evening. I was tuned to the 
> national primary ACARS frequency, which is 131.55 MHz.
> 
> For those of you who haven't tried ACARS, it's worth a listen, especially 
> since it might give a renewed purpose to a dusty old analog scanner in your 
> closet. Having an outdoor antenna will help, but here in the DC area, 
> there's probably enough close-by flights to be able to get at least some 
> ACARS hits with an indoor antenna near a window. You can quickly judge how 
> successful your setup might be just by tuning to 131.55 and seeing how many 
> bursts you hear.
> 
> I'm still experimenting, and have it running now at my apartment in 
> Arlington, getting bursts about every ten seconds or so with my rooftop 
> discone (no pre-amp, since there's too much RF in the area). I need to learn 
> more about deciphering some of the ACARS information.
> 
> Highly simplified tips and tricks from ACARS experts would be appreciated --  
> for example, are there "local" ACARS frequencies for DCA and/or IAD?
> 
> Cheers,
> Andy 
> 
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