[Battlemesh] 5 Ghz wifi: where did channel 32, 68 and 96 go?

[Kristoff]

Hi all,



(I posted this this morning but for reason, it did not get on the list, 
nor the archive. 2nd try. My appologies if it gets posted twice).



I am still new to meshed networking (mainly interested from a ham-radio 
point of view), so please excuse my (perhaps lame) questions.


I am currently reading  some stuff on wifi, especially concerning the 5 
Ghz radio-spectrum.

When looking at the European frequency map (as found or efis.dk), it 
notes the three bands for rlan: 5.150-5.250, 5.250-5.350 and 5.470 to 
5.725 Ghz

Concerning the low bands, concidering 20 Mhz of bandwidth, I would have 
exepected to see 10 channels (200 Mhz / 20 Mhz), starting with channel 
32 up to 66; but I only see 8. The channel 5.150-5.170 (which I guess 
should be channel 32- and 5.330-5.350 (channel 68) do not seams to exist.
The same thing for would-be channel 96 (5.470-5.490 Ghz).


Is there a technical reason for this?
Adjecent-band protection? (these channels are all at the ends of the 
frequency-bands)
Or to provide the primairy users 20 Mhz of spectrum assured without 
interference of wifi ?




Just wondering.

As I am currently playing around with modifying linux kernel-modules (to 
get these devices to operate on ham-radio spectrum), I have concidered 
modifying these modules to access these channels anyway -as a wifi-user, 
not ham-radio-.

I know the regulation might be different from country to country, but 
would it be legal to do this? As far as I see in the Belgian legislation 
only talks about these frequenct bands, not about actual channels.

If I would use a raspi as access-point and linux-clients, that would be 
a nice thing to do. :-)



Cheerio! Kr. Bonne.