Joying JY-UL135 Poor Radio Reception

Anyone else have poor radio reception with the Joying JL-UL135? Previous radios in my 2001 Suburban picked up local stations just fine. This one has a hard time picking up even local stations. I double checked my antenna connections and even bought an amplified antenna. No change. In fact, the radio reception is exactly the same weather the antenna cable is plugged into the back of the radio or not. Is it possible the radio antenna port is not connected internally to the radio?

For reference, this is my radio:
https://www.carjoying.com/android-5-...rt-revers.html