Come to think of it, I've detected within 1/4 mile of a manned Coast Guard station, within 1 mile of a "don't know what kind of military installation it was, but when I drove by I saw a zillion dishes and funny looking antennae there" and lots of cameras and a huge radio tower, I guess for the airport which was 1/2 mile away, and never had a problem with EMI. I also detect directly under power lines. So are some machines prone to EMI death? I just remember once digging with someone who had this huge PI machine, I think it was PI, don't remember which model anymore, I went right behind him with my vlf machine under power transmission lines and pulled out a lot of minies right after he left.