If you are having trouble with interference in your Wireless system, check out this great article from Audio-Technica. They tell you a lot of information about wireless interference including different types, what they are, and how they happen. It would be very useful and beneficial to know these things if you are a wireless system user. Please note that you don’t have to specifically own a specific brand of wireless system for these articles to be helpful!
Also, if you click here, you’ll be taken to Audio-Technica’s “Using Wireless Systems” page where they have links to wireless quick tips, wireless basics, and wireless advanced topics.
Here are even more great troubleshooting guides from Shure.
This one is specific to the PGXD system from Shure: