Truth is a force of nature
- May 7, 2004
Do I need to turn off the squelch while scanning the ACARS frequencies if I am hooked up to baseband audio? I'm using PDW and the signal meter is fluctuating even when squelch is on.
No wonder why I'm not picking anything up. I hear the digital signal, but no decode. I just bought another stereo cable on eBay so I'll try that. I don't want to unplug the discriminator due to all the junk and desk which is in the way. :lol: Hard to explain.Two things here - there is no 'baseband audio' for an AM signal. Discriminators aren't involved in AM signal detection, so a tap isn't likely to work well, nor is it needed. It's a 2400 baud signal, as I recall. A simple connection from your speaker out is usually sufficient. Just watch your levels to make sure you don't overdrive it. If you can use a fixed level audio output, like a record out, you can try it, but there might not be enough signal to drive the soundcard properly.
If your scanner happens to open up quickly enough (some do), then scanning may work. However there is a very quick sync signal that is sent prior to the data, and if your software doesn't hear it, it may not decode. Won't hurt to try it both ways - sitting on a channel with the squelch off, or scanning. See what works better for you
Just to test the three free acars programs kg-acars, acarsd, and pdw. I ran all three together at the same time. kg and acarsd decoded the messages just fine with levels set to what kg said are good. PDW's decode was not very good at all. Labels and messages would be partial decodes that would guess the alphanumeric if it didn't know. The way the message is displayed are similar to acarsd but it looks like a command prompt.
I get very few map plots, one every three-four hours.I'm using KG-ACARS and notice 136.800 has a lot of United. Question: When do I see an aircraft on the map? All I'm getting is link tests and acknowledgements.