A mobile wireless communications device and associated method of making same includes a housing and circuit board having a ground plane. Radio frequency (RF) circuitry and a processor are carried by the circuit board and operative with each other. An antenna is carried by the housing and operative with the RF circuitry. Audio circuitry is carried by the circuit board and operative with the RF circuitry and processor. An audio transducer assembly such as a receiver is carried by the circuit board and engages audio circuitry for carrying audio signals between the audio circuitry and speaker. A filter is mounted at the speaker for blocking RF energy from the antenna through the speaker to the ground plane and decoupling the antenna from the speaker and any other components on the circuit board to minimize any detuning of antenna impedance match and degradation in antenna gain.