I don't have a home alarm system so that rules that out.
I had a small amplified set top antenna and that was receiving fox for a while until it finally just stopped last weekend. I haven't even had a blip since then.
I naturally figured that the outdoor antenna would do the trick. I'm on the road for work until tomorrow but I am going to start hunting for interference when i get back. Reminds me of a time when my mother had an intermittent wireless internet issue a while back, turned out that every time someone called or picked up the cordless phone that would knock out the wireless. Both were the 2.4 GHz.