Dear Chris,
I recommend to use a SDR dongle and raspberry pi (even the cheapest one, I use RPI zero) , you can monitor/receive ACARS from up to 8 frequencies.
I use acarsdec, but I prefer to decode the "modern ACARS" VDL2 this mode contains more information and add also ACARS message. (I'm in Europe, so this mode I think is only working in EU).
For VDL2 I use vdlm2dec both softwares are available on Github.
If you prefer using your scanner, I have the Airnav acars decoder soft.
send me a pm. so I can share it.
Regards.