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 On 3/24/2012 1356, Derek Walton wrote: > HI All, > > I've watched may people speculate about PED's and what they MAY do, so > I decided to go in the lab and make some measurements on my new iPad. > > Obviously conducted is not an option, there's no power cord. > > For radiated emissions to 1 GHz, the device is as quiet as a mouse. It > was only a quick look see, so I set it up as if I were reading a book: > I have no movies loaded yet. > > Clearly there are other options, so if any one would like to chip in > as to the way it should be running when tested let me know and I'll > run when I get a second and post results. > > I'm thinking either playing a game with lots of video or a High > resolution movie. > > Passive headset inserted also, cord unbundled. > > Anything else? > > Cheers, > > Derek. > L F Research - ---------------------------------------------------------------- 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]>
