- Ability of receiver to separate signals on closely adjacent frequencies (channels) is determined by its selectivity
- Switching to a narrow passband can reduce interference
- Usable passband width is determined by the bandwidth of the mode to be received, e.g:
- 200 - 500 Hz for CW
- 1.8 - 2.4 kHz for SSB
- 12.5 kHz for NBFM