Ext. Mic is Recording Chopping Distortion

[John Stenger]

I use an external (Rode Video Micro) Microphone for audio recording on special event videos, shot with my Phone camera, and while recording my own voice on these locations the audio is excellent! however when I'm not speaking, the noise of the crowd talking in the background alone, is producing a Chopping distorted sort of sound, What would cause this? and is there any way to improve it? ..short of changing the microphone. Thanks