Acars problem..

[ryangassxx]

Ok, here's the deal.. I just recently took an interest in receiving acars. I got the acarsd software and got it up and running on my computer.. When I took my scanner and plugged it into my audio line input for my computer for the first time, to my amazement I started getting acars messages right away on screen. Like 6 all within 1 minute.

After a while though they stopped popping up on screen. I unplugged my scanner from the audio jack to try and hear if the data blips were still coming through. They were.. I proceeded to restart my computer, unplug everything replug it in, restart the software. I even went as far as to reinstall my computer's audio driver. No luck... I have not since been able to receive any acars. It just seemingly stopped working...

Now I do not fully even understand this software. When I first got it started I clicked server and connected. So during the time i was receiving the messages, I was connected to the server.. Is it possible that i was actually only receiving acars via some sort of network connection to other users all along, and never really was receiving with my own scanner? Or, does it not even work like that?

So then this brings me to another question... Assuming I never actually DID get any acars via my own scanner, what do i actually need to do in order to get the software reading and working with my scanner.. Is it not as simple as plugging it in and the software automatically detecting it? Do I have to go in somewhere and tell it that I have a scanner connected and for it to begin reading it?


I think there's just a whole lot I have to learn about how this works... Perhaps someone could give me a complete walkthrough...

Just for reference.. I am using a PRO-97 and a wire with an audio jack at each end, connecting one end to my scanner's headphone jack, and the other to my computer's microphone/line in jack.. Is this the proper way of doing it?

Thanks in advance for any help..

 

[DaveNF2G]

I've found that, even with a very strong signal, sometimes ACARS does not decode well. I suspect the problem to be differences in audio processing among various scanner/soundcard combination that can sometimes render the data burst indecipherable to the software.

If anyone can either confirm this or offer a better reason, I'm all ears.

 

[morfis]

In the early days of ACARS decoding I noticed big differences in decode rates when using different radios with the same decoding system. Some radios were vastly superior to others - Yupiteru VT-125 and Win 108 for example outperfromed every Uniden I had access to at the time. GRE radios performed better than Uniden ones generally. Haven't tried the same exercise again since with more modern radios but see no reason for differnces to have all gone away.
Some people had problems with the early soundcard based decoders as they all used Soundblaster standards but these weren't supported by a lot of onboard or cheap soundcards. This area is less likley to be an issue now as soundcards are all far better than they were then and are far more standardised.

 

[kicktd]

I've noticed that even though you can hear the data blips sometimes it just doesn't decode. Also you can change how many passes ACARSD does on the sound buffer in the ACARSD options. Default is 7 but if you have a fast enough computer you can max it out at 10 no problem. I usually chalk this up to 3 things though:

1) Too weak for the software to decode it
2) Duplicate message(s) that the software hides

If you're using ACARSD check the acarsd.ini file for the following lines:

# acarsd can check for duplicate transmissions within a certain time interval
# and prevent them from being displayed. To allow dupes, activate this option.
#DontCheckMsgDupes

Remove the # before DontCheckMsgDupes, save the file and then restart ACARSD

3) Sound buffer didn't decode properly (too much running in the background, etc. etc.) so ACARSD didn't make sense of it.

 

[morfis]

I've noticed that even though you can hear the data blips sometimes it just doesn't decode. Also you can change how many passes ACARSD does on the sound buffer in the ACARSD options. Default is 7 but if you have a fast enough computer you can max it out at 10 no problem. I usually chalk this up to 3 things though:

1) Too weak for the software to decode it

Rare, damaged packets are more usually down to poor audio quality (often volume too high)

3) Sound buffer didn't decode properly (too much running in the background, etc. etc.) so ACARSD didn't make sense of it.

Haven't seen this on any modern PC. Slow speed data like ACARS is very easy to decode even for an older PC under heavy load.

 

[Yokoshibu]

Yeah I agree morfis.... I have usually ended up overdriving the audio into my soundcars.... One thing to check is the ground between your computer and the radio you are using.... if both are plugged into a wall outlet you might have a problem...

on one of my handheld radio's I was running it connected to my computer it would receive fine but would transmit with a hum due to the wall wart transformer that was powering it.

but i have had a few radios and computers that if they were not on the same ground would exhibit the ac hum.... I have had that hum overrun an entire desired strong signal at times.

 

[kicktd]

Depends on the scanner. Such as the Pro-97 will always have that hum when connected to a PC, the only fix (as pointed out to me in another thread) is to take a metal paper clip and have one end touch the antenna plug and the other end touching the cable. Sucks you have to do this but it works.

Also was just tossing out ideas. To be honest there are several several things that can cause problems but without much more info you can't really pin it down.