What detector? (And what type of tower for that matter?) Some machines handle EMI better than others.
If you can adjust your frequency, try that first. A shift of 4 kHz can make the difference between continuous warbling and near silence. If you can "nudge" your frequency up or down a little without changing to another one entirely, so much the better. Sometimes that's enough.
Some places may just be impossible. I have a site with a very interesting history in a local old park. I've found wheaties right next to it, but once you enter the area of high interference, forget about it. It's already driven an E-Trac, a Deus, and a Silver uMax completely berserk regardless of settings, so I'm not sure that anything is really going to be usable in there. Even my Propointer doesn't like it.