A mobile wireless communications device includes a housing and circuit board carried by the housing. Radio frequency (RF) circuitry carried by the circuit board forms a transmitter and receiver. A processor is carried by the circuit board and operative with the RF circuitry. A keyboard connector is mounted on the circuit board. A plurality of Key_Out and Key_In connection lines are carried by the circuit board and connect the keyboard connector and processor. A keypad is carried by the housing and operatively connected to the keyboard connector. A filter is operative with each connection line for limiting degradation in receiver sensitivity.