It looks like superchannel is available free of charge since v4.3, or maybe I'm getting old and have forgotten that I purchased superchannel licenses for all my routers.
Last edited by THG on Thu Dec 03, 2009 1:32 pm, edited 1 time in total.
It's called "Compliance Testing Mode" and allows you to use any frequency that your wireless card supports. This usually means 5Mhz steps from ~4.9 to ~6GHz and from ~2.3Ghz to ~2.6Ghz
This mode should be used either in controlled environments, for testing, or if you have some special permission from the government to use non-standard frequencies.