I am looking through forum in hope to find an Android App I can use on phone to see raw output of my QK-A024 device because like you I almost always are missing big ships on my plotter.
As plotter I use iSailor App on iPad connected to the QK-A024 via wifi. My antenna cable is only 4 meters long and sometimes the AIS and iPad can show ship targets of 15-18 miles away. At the same time targets 1 mile or less away do not show up and they are big ships that should definitly cary AIS.
I don’t have windows computer so cannot check with OpenCPN. It would be nice with simple Android/iOS app that could show list of AIS targets in simple list as raw data from the QK-A024.
I bought the QK-A024 AIS unit to use as security and earsier/safer navigation when I am sailing solo here in Denmark with lots of big shipping traffic routes and it is an amazing big help when it works but very worryring all the time it is not showing ships right in front of me 
kind regards, Peter