Btw, the Polk system is probibly the least expensive ways to get frequency agility.

I fly on channels 19 and 27. There's one guy on my field on 19, and another on 27 (well, actually, there are a couple, but those two are just about the only ones I run in to). We have 3 pair of banned channels at our field due to high power commerical transmitters operating between the RC channels.