How Roku Broadcasts

The Roku 3's WiFi-Direct operates on 5 GHz only (not 2.4 GHz). ROKU uses a WiFi-Direct interface to its new remote control, which utilizes and broadcasts on the same channel that it receives on. This cannot be changed. The result is that there will be interference, even on 5 GHz, causing other devices to either drop the signal intermittently or fail to connect, or halve their bandwidth. Connecting the Roku with an Ethernet cable should resolve interference issues.
 

Referenced from: https://support.roku.com