>
> Here's the descriptions from wikipedia of the 2 things they have at the
> airport: ILS and VOR. Doesn't anything in these explanations stand out to
> you as being particularly problematic, moreso that a normal fm radio wave?
> For the ILS, I live near a small regional airport, so the beam is NOT
> locallized to allow for a backcourse, which means I am exposed to it:
>
> ILS:
>
> A localizer (LOC, or LLZ in Europe)
> antenna<http://en.wikipedia.org/wiki/Antenna_%28radio%29>
> array <http://en.wikipedia.org/wiki/Phased_array> is normally located
> beyond
> the departure end of the runway and generally consists of several pairs of
> directional antennas. Two signals are transmitted on a carrier
> frequency<http://en.wikipedia.org/wiki/Carrier_frequency>between
> 108.10 MHz and 111.975 MHz. One is
> modulated<http://en.wikipedia.org/wiki/Amplitude_modulation>at 90 Hz,
> the other at 150 Hz and these are transmitted from separate but
> co-located antennas. Each antenna transmits a fairly narrow beam, one
> slightly to the left of the runway centerline, the other to the right.
>
> In addition to the previously mentioned navigational signals, the
> localizer
> provides for ILS facility identification by periodically transmitting a
> 1020
> Hz morse code <http://en.wikipedia.org/wiki/Morse_code> identification
> signal. For example, the ILS for runway 04R at John F. Kennedy
> International
> Airport <
> http://en.wikipedia.org/wiki/John_F._Kennedy_International_Airport
> >transmits
> IJFK to identify itself to users whereas runway 04L is known as
> IHIQ. This lets users know the facility is operating normally and that
> they
> are tuned to the correct ILS. The glideslope transmits no identification
> signal and therefore airborne ILS equipment relies on the localizer for
> identification.
>
> Modern localizer antennas are highly
> directional<http://en.wikipedia.org/wiki/Directional_antenna>.
> However, usage of older, less directional antennas allows a runway to have
> a
> non-precision approach called a localizer back course. This lets aircraft
> land using the signal transmitted from the back of the localizer array.
> This
> signal is reverse sensing so a pilot may have to fly opposite the needle
> indication (depending on the equipment installed in the aircraft). Highly
> directional antennas do not provide a sufficient signal to support a
> backcourse. In the United States, backcourse approaches are commonly
> associated with Category I systems at smaller airports that do not have an
> ILS on both ends of the primary runway.
>
> VOR:
>
> VORs are assigned radio channels between 108.0 MHz (megahertz) and 117.95MHz
> (with 50 kHz spacing); this is in the VHF (very high frequency) range.
>
> The VOR system uses the phase relationship between a reference-phase and a
> rotating-phase signal to encode direction. The carrier signal is
> omni-directional and contains the amplitude modulated (AM) station Morse
> code or voice identifier. The reference 30 Hz signal is frequency
> modulated
> (FM) on a 9960 Hz sub-carrier. A second, amplitude modulated (AM) 30 Hz
> signal is derived from the rotation of a directional antenna array 30
> times
> a second. Although older antennas were mechanically rotated, current
> installations are scanned electronically to achieve the same result with
> no
> moving parts. When the signal is received in the aircraft, the FM signal
> is
> decoded from the sub carrier and the frequency extracted. The two 30 Hz
> signals are then compared to determine the phase angle between them. The
> phase angle is equal to the direction from the station to the airplane, in
> degrees from local magnetic north, and is called the "radial."
>
> On 10/21/07, Bill Bruno <[hidden email] <wbruno%40gmail.com>> wrote:
> >
> > The frequencies must be a little different. And FM is not pulsed at all,
> > the carrier just wiggles its frequency. I don't like to call the pulse
> > effects
> > information, although if we knew exactly what transduction systems were
> > being affected I might feel different about that.
> >
> >
> > On 10/21/07, Paul Coffman <[hidden email] <pkcoff%40gmail.com><pkcoff%40gmail.com>> wrote:
> > >
> > > Sorry, I wasn't testing this thing properly - I was using a portable
> > > radio
> > > with headphones, and when I put the headphone in the pot too then it
> was
> > > blocked. I also bought some aluminim screen wire mesh and wrapped it
> > > around
> > > it and it had the same effect. So then hypothetically if I build a
> wire
> > > mesh enclosure for my bed it should have the same effect. This is just
> > so
> > > odd - if I drive up to FM radio towers i'm not bothered much, but
> these
> > > same
> > > frequenecies at much lower power from the airport drive me crazy.
> > Someone
> > > said (Charles?) that is was the INFORMATION in the radio wave that my
> > body
> > > didnt' like - that's the only explanation I can come up with. From a
> > > scientific pov this is nuts.
> > >
> > > --
> > > Paul Coffman
> > >
> > > [Non-text portions of this message have been removed]
> > >
> > >
> > >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
>
> --
> Paul Coffman
>
> [Non-text portions of this message have been removed]
>
>
>