>
> Thanks for the info! In both cases there's AM modulation, and the
> carrier
> is much higher than AM radio.
>
> Do you have info on the power of these signals? (Or the power of the
> transmitter and the antenna gain for the directional ones?)
>
> These are frequencies where the human body could be an antenna.
> If your body is just the right size for a given frequency, maybe
> that's the issue?
>
> Whether or not you are grounded could change your resonant frequency.
>
> Another thing we have not considered is polarization. I assume most
> broadcast stuff is vertically polarized. I would guess the same would
> be true of these airport signals but perhaps not. If you're lying down
> polarization may matter. Try sleeping so your head or feet are toward
> the airport, and keeping away metal stuff that will reflect the signal.
>
> Bill
>
> On 10/22/07, Paul Coffman <[hidden email] <pkcoff%40gmail.com>> wrote:
> >
> > 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><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><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]
> >
> >
> >
>
> [Non-text portions of this message have been removed]
>
>
>