My X5 on Inspire 1 pro has recently been having issues of Weak image transmission and showing blinking images on DJI GO App, sometimes the video image freezes for about 4~5 sec. These issues start when the aircraft is about 600 FT away (Altitude was about 160 FT AGL). I believe it shouldn't show any signal issues within this close range. Any helpful thoughts? Thank you.

What mobile device are you using? Have you changed another one to have a try?
Please prevent the mobile device from direct sunlight with a sunshade, otherwise, the mobile device may warn up and affect the image transmission.
Do you happen to get another RC to test? It would be good for troubleshooting and locate the problem.