Here's tip for anyone who may be having problems with RF interference on their wireless mics. We have eight Shure LX series VHF wireless receivers. All are on frequencies recommended by Shure for our location. Last fall, we began noticing increased interference on several of the units & one in particular. I thought it might be due all the new digital TV stations in Atlanta. The problem continued to worsen through winter & spring until one of the receivers was so intereference prone that it was unusable. After talking with a Shure application engineer several times, she suggested turning off any digital effects devices we might have. As soon as we shut down our Lexicon MPX500 digital multi-effects unit, just about all of the stray RF disappeared from the wireless receivers. I am awaiting a response from Lexicon about possible causes and solutions, since it was in use for around two years before this problem started to show up. Unfortunately, moving the Lexicon away from the receivers (far enough to get rid of the interference) is not an option.