Wireless microphones are also subject to interference from other signal sources transmitted in the same frequency spectrum. The common ones are usually TV stations. FCC rules require users of wireless microphones to avoid using the frequencies occupied by broadcast TV stations in the same geographic area.
Solution: Indoors, avoid interference from 40-50 miles of TV channels. When working outdoors, it should be used normally within a radius of 50-60 miles. Since the frequency of each city is different, the suitable frequency of the wireless microphone depends on the place where it is located. Equipment manufacturers usually provide guidelines to inform users of the different frequency of use in different cities. The FCC required all analog TV stations to cease operations in February 2009. At the same time, the frequency spectrum above channel 51 will be used for other purposes. The frequency of the wireless microphone above 698MHz should be adjusted to a lower frequency to avoid interference with new services. As the conversion continues, the TV channel in a particular location may change, so users are better to check official profile information regularly.