Re: Wireless dropouts mystery...
+1 This is the most likely fix for the trouble you describe, although you may end up moving an antenna a few feet or more.
Also make sure that the polar radiation patterns of both antennas are appropriate for each antenna to cover the entire performance area, and aim them accordingly. If you're using LPDA antennas (paddles), they have around 70 degrees of coverage, which would necessitate their locations to be near the corners of the room, pointed toward the diagonal opposite corner. PWS Helicals are around 60 degrees. Sennheiser A5000CP are around 80 degrees. You might consider omnidirectional antennas if corner locations would be difficult to accomplish.
The performers' short distance (12') to the antennas is relevant, but how long are the coax cables and what type are they? Significant losses occur with long cable runs.
As a professional audio engineer who must use wireless, you'll benefit greatly from studying and understanding Antenna diversity - Wikipedia, the free encyclopedia and Multipath propagation - Wikipedia, the free encyclopedia.
