Blanketing is the interference caused by very strong radio signals. Although the spectral mask of a radio station's transmitter suppresses spurious emissions on other frequencies in the band, being extremely close to a station may allow them to still be strong enough to cause significant interference. The strong station will appear on nearly every blank or weak channel in the band, especially in the FM broadcast band. This problem is greatly reduced by even moderate-quality receivers, which have better selectivity than cheap disposable ones.

Occasionally, stations that cause blanketing interference near their antenna will also pop up in more bizzare items, such as computer loudspeakers, which are not even meant to pick up radio stations. This is also the result of poor (or nonexistent) electromagnetic shielding in such cheap electronics.