 www.srh.weather.gov |
  National
Weather Service Weather Forecast OfficeAlbuquerque, New Mexico |
|||||
|
|
|||||||
|
|
The NOAA Weather Radio Signal
The NOAA Weather Radio signal travels
at the speed of light with a wavelength of about 1.85 meters, or just
over 6 feet in length. At this speed, the
signal would circumnavigate the earth 7 times in 1 second, yet the terrestrial
coverage of the NOAA Weather Radio signal is much more limited. This
is because at Very High Frequencies (VHF), radio waves overshoot
distant locations. Relative to the
traveling radio wave, the ground below recedes due to the earth's curvature. The
radio wave continues on its way into space reaching the outer fringes of
the solar system in a little over 5 hours time. Mountains and unusual
atmospheric conditions can dramatically alter the terrestrial coverage
pattern of the NOAA Weather Radio
signal. Tropospheric ducting and ionospheric refraction, on rare
occasions, have been known to carry VHF radio waves over hundreds or even
thousands of miles. The
current phase of the 11-year sunspot cycle will likely result in more frequent
occurrences of ionospheric propagation through the turn of the millennia. Imagine
hearing the coastal marine forecast from your kitchen on the plains of
Nebraska!
If you can receive the NOAA Weather
Radio signal clearly, from inside your home, then you need not make any
changes. If however, the signal is
weak, scratchy, or nonexistent and you live within 40 to 50 miles of a
NOAA Weather
Radio transmitter, then you can try a few things to improve signal reception.
The higher the antenna, the better.
If your weather radio has a built-in antenna, try moving the radio to
a higher spot, like a shelf or bookcase. Also, moving the radio
to the area of your home facing the transmitter location, especially
near a window, can produce a marked improvement of the signal.
Okay, let's try something else. Remember
that the wavelength of the NOAA Weather Radio signal is around 6 feet
in length. This means that an antenna
resonant to the NOAA Weather Radio frequencies (162.400 MHz - 162.550 MHz) will best serve
listening at a length of 6 feet or greater. To achieve this, cut a piece of copper
wire to extend the overall length of the antenna to 6 feet or longer. Attach the
wire to the end of the radio antenna by using an alligator clip, or any clamping device,
which will ensure a steady contact of the copper wire to the radio antenna. Ideally, it is
best to extend the wire vertically and as high up as possible. Extending the wire
horizontally along the ceiling may work for you, but the NOAA Weather Radio signal is
vertically polarized, meaning by theory, a vertically extended antenna will out perform a
horizontal one. Do what works for your locale.
If you have a weather radio with
a built-in, fixed antenna, you may be out of luck. We've done our best
in the above steps. However, if your radio has an
external antenna jack, or a detachable antenna connection, then we have
the means to employ an outdoor antenna. You can attach a coaxial cable
from your radio to an external
antenna mounted on the roof, in the yard, or on a balcony. Mounting
the antenna outdoors and perched high will vastly improve the signal reception.
But it does not come
without a price. If you mount an outdoor antenna you must make provisions
against the danger of lightning. This is done by grounding the antenna.
Please consult your local
electronics or radio outlet on the proper way to ground your radio system.
Many popular handheld radio scanners have the capability to tune into the
NOAA Weather Radio signal
with the press of a button.
If you still can't pick up the NOAA Weather Radio signal, then
please contact the NOAA Weather Radio Focal Point at our office.
NWR Focal Point
National Weather Service Forecast
Office
2341 Clark Carr Loop SE
Albuquerque, NM 87106-5633 or
E-mail: sr-abq.webmaster@noaa.gov
|
|||||||||
