I think I am on to some thing.
Notice that the channel range is 3 - 75. There are 37 odd channel
and 36 even channel. So I redraw the distribution graph separate
out the even and odd channel. That make the graph much smoother.
Here is what I get, the blue line is even channel. The green on is odd
The questions is, what kind of method was used to result in that
kind of the distribution?
Notice that the distribution graph have 3 separate bar. It is pretty
flat within the bar. So my guess is that, the channel selection is
using segmented selection.
The channel is split into 3 zone: low, mid and high.
odd channel: 3-27, 29-51 , 53-75
even channel: 4-26, 28-50, 52-74
So out of the 23 channel, 23 can't divided by 3. So that will
explain the middle dip. My guess was that, 8 was coming from
low, 7 was coming from mid, 8 was coming from high.
I just run a program to verify that. YES! All the channel selection
match the [8,7,8] distribution in the 3 zone. There is no
exceptions in my 28K guid samples! I think Spectrum want
to spread the 23 channel selection, not clump into same zone.