If your problem is simulcast, a better antenna will make it worse. When dealing with a simulcast site, less signal is more. If you reduce the signal level, it will reduce the number of subsites you receive and that can improve control channel decoding. Try turning on the attenuator and pointing the antenna in various directions. If you move the scanner around the room, you may find a sweet spot where it works. If you attach your file, we can determine if it is a programming problem.