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 dont yet know is, on a co-secondary arrangement, who is primary? Ill 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. Glenn. [1] C Band; RF from 4 to 8 GHz http://en.wikipedia.org/wiki/C_band [2] 802.11a frequencies http://www.moonblinkwifi.com/80211a_frequency_channel_map.cfm [3] Ham frequencies; CFR 47-97.301(a) http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/pdf/47cfr97.301.pdf [4] Ham requirements; CFR 47-97-303(a)(b)(m) http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/pdf/47cfr97.303.pdf [5] Space bands; CFR 47-97.207 http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/pdf/47cfr97.207.pdf [6] Earth stations; CFR 47-97.209 http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/pdf/47cfr97.209.pdf [7] ITU region map http://www4.plala.or.jp/nomrax/ITU_Reg.htm [8] Amateur transmitter power standards http://a257.g.akamaitech.net/7/257/2422/13nov20061500/edocket.access.gpo.gov/cfr_2006/octqtr/pdf/47cfr97.313.pdf _______________________________________________ psas-avionics mailing list psas-avionics@lists.psas.pdx.edu http://lists.psas.pdx.edu/mailman/listinfo/psas-avionics
