When we first started doing launches I was also trying to catch my own APRS packets. I was on a Lenovo PC with an AirSpy SDR...and no luck. I switched the whole works over to a Dell, and it worked easily. I believe that the issue was the sound card on the Lenovo. I did end up purchasing an external SignalLink USB Sound Card/Radio Interface and the sound card was not an issue anymore. But we don't do this anymore - we just rely on the APRS system.
However, sometimes when we were out on the chase we had trouble getting the APRS signals on our radios. We believe that we were in the antenna blind spot (directly underneath the antenna). None of that mattered at altitude since our balloon APRS was heard by stations as far as 400 km away.
Near the landing, when the payload is low, it is helpful to hear the APRS independently. Some of the radio club guys come out for the chase and their car radios receive and transmit our APRS packets, but the signal can get lost behind a large obstacle. So for ground recovery we use a Spot trace tracker that communicates directly with satellites, which I would recommend if you are in hilly terrain.