Baofeng UV-5R For APRS Packet Receiver

Dear Community:

I am a mechanical engineer just starting out with radios and electronics. I am using a BAOFENG UV-5R as a receiver for APRS packets and then connecting the UV-5R via the audio port to an Arduino Radio Shield 2 shown here:

Overall, the system does work, but we are only able to decode about 1 packet in 50 and I don’t understand why. The APRS transmission is fixed and whatever delays, etc. are there, can’t be changed. The Radio Shield has a simplistic demodulator, but given that it works some of the time, I would think there is hope to get it working ALL of the time. I am hoping that someone out there has done something similar and knows a trick or two that might help me out. There are any number of settings on the BAOFENG that I simply don’t understand and one of them might be the key to making this thing work better. Any help at all would be appreciated.