Could be a interesting topic with more and more stuff going wireless, also noticed in previous video's a pair of sennheiser EW100 wireless (microphone)
transmitters (or was it one transmitter and one bodypack receiver?) and a nice rf spectrum analyzer...
If Dave has two transmitters get them spaced 200khz apart and see what happens on the analyzer.
These days it is getting more and more difficult to get a decent number (30 or so) of these wireless audio connections reliable working in the crowded ether.
Maybe a trip to the opera house to see how they are doing?