I am a new member so can't link to the YouTube video I made demonstrating this phenomenon. I can't post a link because I'm a new user, but it's titled: Nvidia shield tablet bad WiFi design, don't buy a lemon.
Another YouTube posted a video a week ago showing the same effect. His video is called: Nvidia shield tablet, how to hold your tablet in your lap.
I'm on the 2.4ghz band in the video only a room away. Does it happen to you guys too? Do you have any other issues with the WiFi on this thing?