I agree totally with Mr. Townsend. The idea that out-of-band cell phone transmissions will cause GPS failures is unwarranted. The reason for not using cell phones at altitude is just as Mr. Townsend states, to protect the cell phones, not the aircraft.
All non-antenna connected electronics on an aircraft are fully protected by susceptibility requirements of RTCA/DO-160 section 20. If there happened to be aircraft receivers operating in cell bands then there would be the possibility of rfi. I don't believe there are such systems at the present time, but I could be wrong. It certainly would not make any sense at all to in the future install critical function receivers operating in the cell band(s) given that sooner or later some one will use his/her phone when they aren't supposed to - did we really need a study to tell us that? Ken Javor on 3/2/06 2:20 PM, Fred Townsend at [email protected] wrote: > The information is indeed interesting. I also find it is interesting the > study did not cite any actual interference. They used an onboard > spectrum analyzer to verify people actually used, or tried to use their > cell phones. If we set, as a standard, any level of potential > interference, then the airplane should never fly because of the > potential of the airplane to interfere with itself from its own > navigation and communications systems to say nothing of digital fly by > wire. What about the 'glass cockpit'? It's full of digital devices in > close proximity! What about that local radar that paints the airplane > with very high level microwaves just as the plane is landing. Shouldn't > we be focusing on immunity standards for the cockpit? After all, mother > nature puts out signals too. Ever catch a lightning burst on your > spectrum analyzers? > > Second related subject: The cell phone design depends upon frequency > reuse and hand-off from cell to cell. This works well when the airplane > is on or near the ground. Both of these techniques are defeated when the > radio is airborne, particularly at high altitude. The same radio is > seen by multiple cell sites causing multiple responses. The tracking > system will be confused by multiple reports of the same CID. This > reduces the available frequencies as well as confusing the cell phone > itself. This is going to result in dropped calls for all users. Seems > like the system needs to automatically detect airborne operation and > disable the CID. > > Fred Townsend > > > Nick Williams wrote: > >> I know quite a few subscribers to this group will be interested in this: >> >> http://www.theregister.co.uk/2006/03/02/aircraft_mobile_phone_risk_study/ >> >> Regards >> >> Nick. >> >> - >> ---------------------------------------------------------------- >> This message is from the IEEE Product Safety Engineering Society >> emc-pstc discussion list. Website: http://www.ieee-pses.org/ >> >> To post a message to the list, send your e-mail to [email protected] >> >> Instructions: http://listserv.ieee.org/request/user-guide.html >> >> List rules: http://www.ieee-pses.org/listrules.html >> >> For help, send mail to the list administrators: >> >> Scott Douglas [email protected] >> Mike Cantwell [email protected] >> >> For policy questions, send mail to: >> >> Jim Bacher: [email protected] >> David Heald: [email protected] >> >> All emc-pstc postings are archived and searchable on the web at: >> >> http://www.ieeecommunities.org/emc-pstc >> >> >> > > - > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to [email protected] > > Instructions: http://listserv.ieee.org/request/user-guide.html > > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > > Scott Douglas [email protected] > Mike Cantwell [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] > David Heald: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
