Yes and no. Both devices continued to function correctly. And both passed emissions. But when near each other, the immune nature one amplified the emissions of the other. A bit of a surprise for the hf radio guys, they said something about way out of band... I figure the kHz is modulating the suppy to the MHz power amps. The point being that some complant PED could couple and mix with an existing system to create a problem for a third system by exceeding test levels. - Bill on Wireless Phone
Brian Oconnell <[email protected]> wrote: >Are you saying that the problem, for this incident, is with the immunity >part of the standard? > >-----Original Message----- >From: Bill Owsley [mailto:[email protected]] >Sent: Monday, March 26, 2012 2:20 PM >To: [email protected]; [email protected] >Subject: Re: [PSES] New immunity testing by the FAA in the future? > >An interesting situation I ran into; a 10's of kilohertz system with lots >of harmonics that faded fast, got into a 915 MHz radio which then amplified >a wide range of the kHz harmonics to levels notably above the FCC limits. >Broadcasting on all frequencies for your listening enjoyment! > >From: Brian Oconnell <[email protected]> >To: [email protected] >Sent: Monday, March 26, 2012 12:42 PM >Subject: RE: [PSES] New immunity testing by the FAA in the future? > >There ARE problems with some devices, but the ipad may not be a problem. > >USMC aviators have been using ipads in helicopters for almost two years >(that I know). In same squadrons' aircraft, there have been reports of >interference from other "external-use cockpit devices". Marine combat >aviation is a harsh environment, but the equipment has better support than >commercial aviation (you can work the techs unlimited hours and not incur >additional expense). > >Brian > >-----Original Message----- >From: [email protected] [mailto:[email protected]]On Behalf Of Cortland >Richmond >Sent: Sunday, March 25, 2012 4:51 AM >To: [email protected] >Subject: Re: [PSES] New immunity testing by the FAA in the future? > >Hi, Derek (and group). > >Many of us have over a long career had the chance to work on aircraft >systems (or others) for which immunity standards are imposed. In most >cases the signals emitted from properly functioning, >non-intentional-emitter PED do not ever reach the levels the subject >equipment is required to tolerate. IMO, it is in those cases still not >proper to say PED operation should be permitted during flight regimes. >There remain sensitive spectra be investigated; VHF communications, VHF >and UHF navigation and landing systems, IFF, DME/TACAN and TCAS systems >and the like. There have actually been ASRS reports of PED's affecting >flight situation indicators and ILS flags, so for such victim devices, >it seems we do need to test to levels of emissions and likely at levels >lower than those permitted normally. > >Intentional emitters are quite another matter -- see ED-118 re threat >levels -- and systems that react to them may never have been tested >against the particular threat one may pose. While DO-160 threat levels >are higher than most of the PED's a person might bring aboard, most of >the tests use a nominal modulation only ASSUMED suitable for the >purpose. I am now thinking about the famous case of a GSM telephone >which, being under 30 cm from a victim (oven controller) device, turned >on a gas broiler and almost caused a fire. It does not help that those >who make and sell aircraft systems have a great deal of incentive to do >only the minimum required testing, and a good deal of disincentive to >spend time going beyond that. We simply have not tested against all >threats a passenger might carry, and this is another thing missing from >our analyses. > >Some years ago I had occasion to test an automatic external >defibrillator for emissions in the aircraft VHF and UHF comm, navigation >and landing frequencies, IFF, TACAN/DME and TCAS ranges. It appeared >at the time that none of the personnel at the firm I was then on >contract to (or at the test labs being used) had ever done such a test. > >But it is OUR business to know the test is needed -- and if possible, >see it gets done. I was writing the verification plan and was able to do so. > > >Cortland Richmond > >- >---------------------------------------------------------------- >This message is from the IEEE Product Safety Engineering Society emc-pstc >discussion list. To post a message to the list, send your e-mail to ><[email protected]> > >All emc-pstc postings are archived and searchable on the web at: >http://www.ieee-pses.org/emc-pstc.html > >Attachments are not permitted but the IEEE PSES Online Communities site at >http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used >formats), large files, etc. > >Website: http://www.ieee-pses.org/ >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]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ 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]>
