NPSTC has been following the issue of interference caused from some LED and fluorescent light system ballasts, which have disrupted both public safety communications and cellular wireless systems. We have also been informed that some USB3 powered computer hubs will cause interference to public safety portable radios operating in the 700 MHz band. NPSTC will publish a formal survey on this topic in early November.
Currently, NPSTC is working with the American Radio Relay League (ARRL) to learn more about the extent of this problem. ARRL has been doing extensive research and testing into different problems and scenarios. In 2013, the FCC issued an order directing General Electric (GE) to make some changes to their LED lighting transformers after complaints were received about interference. http://transition.fcc.gov/Daily_Releases/Daily_Business/2013/db1028/DA-13-2077A1.txt
PC World also has a story about night time interference in Los Angeles when a 41-story office building turns on its lights, which creates RF noise that drowns out a nearby Verizon Wireless tower. http://www.pcworld.com/article/2095940/la-buildings-lights-interfere-with-cellular-network-fcc-says.html.