A wireless signal drop-out is a lost signal between the transmitter and the receiver, resulting in loss of audio or extremely noisy audio.
Typical causes of drop-outs include:
Interference from a competing signal
Interference from a reflection of the original signal
A physical obstruction in the wireless path between transmitter and receiver
Unfortunately, drop-outs are all but unavoidable with single-antenna wireless systems. The use of a Diversity Wireless System virtually eliminates drop-out problems.