Yep. And hell yeah make em yourself. I made 4 4'x2'x6" panels for $100, not counting the cost of beer. Not to dog the places that make and ship em to you, but they cost like 4x as much. I'm making 4 wedges for the corners next, ala:
Thanks everybody, I am looking into building my own broadband traps now AND using the big room. Simply out of curiosity, anyone built a portable one? Useful? Better?