A multiple carrier adaptive notch filter (ANF) module selectively filters a received wideband communication signal To determine the presence of narrowband interference, the multiple carrier ANF module scans various known narrowband channels that lie within the frequency spectrum of the wideband communication signal and determines signal strengths for each of the narrowband channels. The signal strengths from the narrowband channels are compared to a threshold that is derived from a statistical combination of the narrowband signal strengths. Narrowband channels having signal strengths that are greater than the threshold are determined to have interference.