Jim and All Who have been following the thread,
I am in a very busy time right now, or else I would provide some specific
article references. I can tell all of you a couple of facts:
1. Yes, the IEEE EMC Society has published some papers pertaining to the
use of cell phones (as carried on by passengers - not the GTE Airfone
system), as well as various "PEDS" (Portable Electronics Devices).
Studies of propagation in the GSM band aboard aircraft were presented over
the past few years by research teams in Germany and Italy, to name two.
One of the plots that I recall very well from the German study (using an
Airbus aircraft) was the significant radiation around the doors, as
compared to the windows. The studies were done on parked aircraft, not
airborne. You will have to search the IEEE EMC Symposium Proceedings from
the past several years to find these papers. Other articles may well have
been published in the IEEE EMC Society Journal, but none come to mind at
this time.
2. Another organization that is conducting related studies for cell phones
and PEDS is RTCA, Inc. They publish the electromagnetic environmental
standards used for many civilian aircraft, and those standards are
developed by committees consisting of representatives from the air frame
manufacturers, avionics manufacturers, the FAA and other national bodies
associated with aircraft regulations, the FCC, pilots, and EMC test
facilities.
3. RTCA DO-160E, Section 20, specifies the radiated susceptibility
requirements that are used for most civilian "major size" aircraft (fixed
wing and rotary wing). The requirements are based upon a number of factors
that include the existence of high RF levels in parts of the spectrum
around the aircraft, with allowances for any attenuation that may exist
between the RF source and the subject avionics device. Keep in mind that
no amount of testing can compensate for on-channel interference; these
requirements are meant to show that a given piece of equipment will work as
intended within the parameters of widely accepted criteria. I might add
that the external environment reference (for volts/meter versus frequency)
is the same as used for many military programs, and some test levels for
DO-160E are as high as 300 V/m (for CW signals, higher for pulsed signals).
4. The standard for military aircraft EMC is MIL-STD-461E (soon to be
replaced by 461F). In general, external susceptibility is 200V/m for
aircraft, with higher requirements for certain applications using the same
external electromagnetic field reference as mentioned above.
This is not meant to be an all-inclusive answer to the many good questions
raised under this thread, but I did want to address Jim's IEEE comments and
to inform the rest of you that yes, civilian aircraft are subject to very
high EMC standards. Over time, the civilian and military EMC requirements
have been on converging courses, and that's a good thing. One example:
many military programs now reference the civilian RTCA DO-160E document,
Section 25, for ESD (electrostatic discharge) performance requirements and
test methods.
Details about cell phone usage aboard aircraft are still in development.
One trend points toward the flying pico cell approach (as discussed by a
few of you), which would keep cell phone RF power within the flying hull
quite low. The preferred link is to satellite, rather than direct to
ground stations. As you know, data services and Internet are now available
on some carriers for those passengers with laptops.
73, Dale, WA9ENA
NARTE-certiffied Senior EMC Engineer
Rockwell Collins
"Jim Brown"
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Re: [RFI] Fw: cell phone
03/02/2006 10:00 interference on airplanes
PM
Interesting. Has anyone seen this IEEE Spectrum piece? It is my
understanding that there is a lack of peer review by the editors of
IEEE Spectrum, and that "studies" with less that solid basis have
been published in Spectrum. The logical place for a real technical
work on this topic would be in the IEEE Journal on EMC. Has anyone
seen such a paper?
Jim Brown K9YC
On Wed, 1 Mar 2006 11:05:52 -0600, Dave NØRQ wrote:
>I hadn't seen this mentioned, and thought it interesting...
>Carnegie Mellon engineers have found that cell phones and
>other devices on an airplane can indeed cause interference
>to the operation of the plane. Details at
>http://www.post-gazette.com/pg/06060/662669.stm
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