Did some tests on the RT-N16, and found out I really have to put load on it to make the true signal visible
Yet, for the ppl who like to see the raw values:
rt-n16 default: http://i52.tinypic.com/2rzuyib.jpg
rt-n16 upper: http://i55.tinypic.com/2i052jc.jpg
rt-n16 lower: http://i55.tinypic.com/2mpztpz.jpg
rt-n16 20mhz: http://i55.tinypic.com/2yukaco.jpg
Now, I measured the following results by downloading a file from the usb stick
defaults with load (channel 11, lower 2nd channel):
lower, surprisingly it shows the higher channel is used.
central channel is 6:
higher, surprisingly it shows the lower channel is used.
central channel is 6:
20MHz
for the 20mhz band it looks like it's just adding a secondary 20mhz band on the same frequency range