Roku WiFi Issues

I have a Roku that I bought after Christmas, and it worked fine on our U-Verse WiFi. I recently ditched cable and just have Charter Internet, which is supposed to be much faster and just looking at how my computer, iPhone, iPad, and Kindle Fire are working I would think so. But for some reason the Roku can't stay connected to my router. I even moved the router upstairs so it would be closer to the computer and the Roku. I tried a factory reset the other night, and that didn't do it. Finally just unplugged it, and then after a couple of days I plugged it back in, it went through the normal set up, and we were about 10 minutes into a show when it froze up. I got back to the settings menu and sure enough it wasn't connected, and when it scanned for networks nothing showed up, even though my iPhone was connected to the same network with no problems.

Is this a common issue with these? I know it isn't a router problem since my phones can pick up good signal anywhere in the house and most of my yard. It is maybe 20 feet from the router to the Roku, and no walls or anything in the way. Just a short hallway and an open door.