I have looked at the intersection of frequencies in the C band [1]  
between IEEE 802.11a and the amateur radio service, and there is  
_some_ good news. The 802.11a frequencies [2] are broken up into  
"bands of channels" named Lower, Middle, H, Upper, and ISM. The  
amateur service in the C band [3] has terrestrial, earth station, and  
spacecraft segments. All of the Upper and ISM 802.11a channels are in  
the amateur terrestrial range; namely channels 149, 153, 157, 161, and  
165. Upper channel number 153 is also in the amateur earth station  
range. Unfortunately no part of  802.11a is in the amateur spacecraft  
range. This kind of makes sense with regard to interference, since it  
would be so easy for a spacecraft to interfere with a large number of  
terrestrial 802.11a stations.

The rules and regulations state that the amateur station cannot cause  
harm to services in other ITU regions [7], (we live in ITU region 2);  
and the amateur station is secondary to the Federal radiolocation  
service. On 802.11a channel 153, amateurs are co-secondary with  
deep-space service. All but channel 153 are secondary with ITU-1 fixed  
satellites, and are co-secondary with ISM services in all ITU regions.  
Note that 802.11a is partly in the ISM service band. Channel 153 is  
secondary to “other nations” radio location services.

So we can work the 802.11a channels in the amateur service on a  
secondary basis. Secondary use essentially says you cannot cause  
interference to the primary service, and must accept interference from  
the primary service. One thing I don’t yet know is, on a co-secondary  
arrangement, who is primary? I’ll try to find this out. Power levels  
are limited to the license class [8], which for the technician class  
is 200 watts, and the overall power limit stated in CFR 47-97.313(a)  
and (b).

The way I see it, using 802.11a will work for us up at larger amateur  
power levels until we actually get into space, and either need the  
higher power levels (more than 3 watts say) for the link budget, or  
our footprint increases and we actually become a spacecraft.


[1] C Band; RF from 4 to 8 GHz

[2] 802.11a frequencies

[3] Ham frequencies; CFR 47-97.301(a)

[4] Ham requirements; CFR 47-97-303(a)(b)(m)

[5] Space bands; CFR 47-97.207

[6] Earth stations; CFR 47-97.209

[7] ITU region map

[8] Amateur transmitter power standards

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