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

Kristoff kristoff at skypro.be
Fri Mar 4 10:16:56 CET 2016

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 
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.

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