How can i fix the image noise?

hello everybody
I use digital image transfer system for my own Quadcopter , But in the tournament, the image was Strongly Noise and i could not fly the quadcopter.
I have a Noise in both frequencies (2.4 And 5 Giga Hertz)
Both the car camera and a webcam has Noise.
My dongle is Asus AC56 , and my router brand is TP_LINK and it has 3 antennas
Please guide me what to do that image does not have a Noise?
Meanwhile I use Raspberry pi 3
Thank you for your help.