The NOAA All Hazards Weather Radio System - What it is and what you can do to improve reception of the broadcasts
Live Streaming Audio of select NOAA All Hazards Weather Radio broadcasts !!
Other NWR Feeds
Reporting a Transmitter Problem
List of ME and NH NOAA Weather Radio Stations
List of Weather Radio County FIPS Codes for Maine and New Hampshire
List of Weather Radio Manufacturers
Local NOAA Weather Radio Pamphlet (in pdf format)
National NOAA Weather Radio homepage
RECALL of Some NOAA Weather Radio Receiver Models
What is NOAA Weather Radio?
The National Weather Service provides local weather broadcasts, called NOAA Weather Radio,
from over 700 different transmitters nationwide. It is estimated that over 85 percent of the
population now resides within the service area of at least one transmitter.
NOAA Weather Radio is a service of the National Oceanic and Atmospheric Administration (NOAA)
of the U.S. Department of Commerce. As the "Voice of the National Weather Service", it provides
continuous broadcasts of the latest weather information from local National Weather Service
offices. Weather messages are repeated every 4 to 7 minutes, and are routinely updated every 1
to 3 hours or more frequently in rapidly changing local weather, or if a nearby hazardous
environmental condition exists. This service operates 24 hours a day.
The regular broadcasts are specifically tailored to weather information needs of the people
within the service area of the transmitter. For example, in addition to general weather
information, stations in coastal areas provide information of interest to mariners. Other
specialized information, such as hydrological forecasts and climatological data, are also broadcast.
During severe weather, National Weather Service forecasters can interrupt the routine weather
broadcasts and insert special warning messages concerning imminent threats to life and property.
The forecaster can also add special signals to warnings that trigger "alerting" features of specially
equipped receivers. This is known as the tone alert feature, and acts much like a smoke detector in
that it will alarm when necessary to warn of an impending hazard. In the past, ALL receivers equipped
with the tone alert feature within the listening area would alarm anytime a warning was issued. However,
the advent of Specific Area Message Encoding (SAME) technology, permits newer receivers to alarm only if
a warning is broadcast that pertains to your particular location. The newer receivers allow you
to choose which warning locations your receiver will alarm for. For example, your particular NOAA Weather
Radio listening area includes counties A, B, C, and D and you live in county A. The original tone alert
Weather Radio would alarm anytime a Warning was issued for any one of these counties. The new SAME Weather
Radio will alarm for just your county (A), or for any combination of counties you choose. With the new SAME
Weather Radio technology it's YOUR choice which warnings the radio alarms for.
Under a January 1975 White House policy statement, NOAA Weather Radio was designated the sole
government-operated radio system to provide direct warnings into private homes for both natural
disasters and nuclear attack. This concept is being expanded to include warnings for all hazardous
conditions that pose a threat to life and safety, both at a local and national level.
NOAA Weather Radio currently broadcasts from over 700 FM transmitters on seven frequencies in the
VHF band, ranging from 162.400 to 162.550 megahertz (MHz) in fifty states, Puerto Rico, the Virgin
Islands, Guam, and Saipan. These frequencies are outside the normal AM or FM broadcast bands.
How can I receive these broadcasts?
Special radios that receive only NOAA Weather Radio, both with and without the tone alert feature,
are available from several manufacturers. The radios can usually be found at department and
electronics stores. In addition, other manufacturers are including NOAA Weather Radio as a special
feature on an increasing number of receivers. NOAA Weather Radio capability is currently available
on some automobile, aircraft, marine, citizens band, and standard AM/FM radios, as well as
communications receivers, transceivers, scanners, and cable TV. If you own a programmable scanner
try punching in each of the seven frequencies listed below. In most areas, you should be able to
receive a weather broadcast station on at least one of these frequencies.
The seven specific frequencies used by NOAA Weather Radio are:
162.400 MHZ ;
162.425 MHZ ;
162.450 MHZ ;
162.475 MHZ ;
162.500 MHZ ;
162.525 MHZ ;
and 162.550 MHZ.
NWR Broadcast Stations Serving Maine and New Hampshire
You can click on either of the maps below to see the location and frequencies of NOAA Weather
Radio Stations serving Maine and New Hampshire. The white area on the maps is where reliable
reception can be expected. The green area on the maps is where reception will be unreliable
at times. The red area on the maps is where reception is improbable.
RECEIVER RECALLS
For information on Weather Radio receiver recalls, go to the
U.S. Consumer Product Safety Commission
(CPSC) web site and choose "Radios (Weather)" in the product Type list.
- back to the top -
How can I improve my reception?
By nature and by design, NOAA Weather Radio coverage is typically limited to an area within
40 miles of the transmitter. The typical service area, or range of a weather radio station,
can best be approximated by a circle having a radius of 40 miles from the transmitting antenna.
The quality of what is heard is dictated by the distance from the transmitter, local terrain, and
the quality and location of the receiver. In general, those on flat terrain or at sea, using a high
quality receiver, can expect reliable reception far beyond 40 miles. Those living in cities
surrounded by large buildings, and those in mountain valleys, with standard receivers may experience
little or no reception at considerably less than 40 miles. If possible, a receiver should be tested
in the location where it will be used prior to purchase. A more in-depth technical discussion of
NOAA Weather Radio and improving your reception can be found below.
If you have a question regarding the weather information broadcast over NOAA Weather Radio, please
contact the local National Weather Service office that does the programming for the station. Contact
information can be found at the lower left hand side of this document.
Radio Receivers and Methods to Improve Reception of
Weather Radio Broadcasts
Please note: The text and graphics on this page were
taken from a National Weather Service publication of the same
title. Within the text, there are references to these graphics.
Click the link and the graphic will open in a new window. In
addition, all of the graphics are available at the bottom of
this page.
The continuous weather radio broadcasts of the National
Weather Service range between the frequencies of 162.400
megahertz (MHz) and 162.550 MHz. These frequencies are in a
band referred to as Very High Frequency (VHF) that extends
from about 50 MHz to around 175 MHz. The frequencies used by
commercial FM radio stations occupy the lower portion of this
band. Also the middle channels of VHF television broadcast in
this band. Because of the physical characteristics and
behavior of VHF broadcast signals, it is not uncommon to find
owners of weather radios, like owners of commercial FM or TV
receivers, experiencing difficulty receiving a suitable
broadcast even though they are within or near the normal range
of the transmitter.
The typical service area or range of weather radio stations
can best be approximated by a circle having a radius of 40
miles from the transmitting antenna. Technically, the National
Weather Service (NWS) attempts to provide an unobstructed
signal level of 8 microvolts to receiving antennas 6 feet
above ground at 95% of all points within a radius of 40 miles
from the transmitter. This is not always possible because of
local terrain features such as valleys, mountains, large
buildings, etc. Another factor which could reduce the signal
level is where the transmitting antenna is mounted on the side
of the tower (i.e. the top is already occupied by another
antenna). The signal is then reflected off the face of the
tower creating a radio shadow, much the same as a light
shadow, on the opposite side of the tower. Depending on the
width of the tower face, antenna height, and transmitter
power, the tower shadow can be quite significant. The NWS
office operation the weather radio station can tell
prospective weather radio users if and where such a shadow
exists. You should also refer to the computer generated
broadcast coverage maps above for each station. The table of
coverage maps will give you a better idea of what reception
should be like in your location for a given broadcast station.
Weather radio receivers, both crystal-controlled and
tunable, capable of picking up the weather radio broadcasts,
are available in a variety of styles and prices. The price is
usually proportional to the sensitivity and quality of the
receiver. Below are listed the technical specifications to
look for when purchasing a radio. The specifications can be
compared to those found in the radio operator's book that
accompanies each radio. The individual radio specifications
can usually be found near the front or back of the booklet.
This comparison will help the purchaser make a wise and
informed choice of radio. For further clarification or
assistance, a purchaser may wish to consult with a local
electronic supplier or technician. The NWS recommends the
public purchase receivers with a 0.5 to 1.0 microvolt
sensitivity for 20 decibels (dB) quieting, a selectivity of 45
to 70 dB down at +/- 25 kilohertz (kHz), tunable or switchable
to all frequencies, a warning alarm feature, dual power source
of AC/battery with automatic switchover to battery during
commercial AC power outages, and a collapsible or fixed indoor
telescoping antenna with a provision for an external antenna
input connection.
If the owner has a weather radio meeting the general
specifications outlined above in proper working order or a
lessor quality radio and still cannot receive an acceptable
broadcast, the cause can usually be found to be: A) too weak a
signal due to distance from the transmitting antenna or loss
of signal penetrating into a building. B) a geographical or
man-made obstruction C) interference from another station on
the same frequency (co-channel interference).
It must be remembered the signal gets weaker the further
one gets from the transmitter. The strength of these signals
on the average becomes quite weak at distances greater than 35
to 45 miles. Also, when the receiving antenna is inside a
building (not in an open area) some of the signal will be
absorbed and/or reflected by the materials which make up the
building resulting in further loss. Buildings constructed of
steel and masonry products usually attenuate or weaken the
signal more than wood or frame construction. Locations below
ground are the worst locations for receiving such a broadcast.
The methods described later are frequently not effective at
distances greater than 50-60 miles. Distances on this order
and greater are beyond the distance for which broadcast
programming is intended or provided.
Geographical obstructions that cause reception problems are
usually mountains, a large ridge or hills located between the
transmitting and receiving antennas. Man-made obstructions may
be classified as large buildings or other structures between
the transmitting and receiving antennas resulting in weak or
complete loss or signal. Tower shadows would fall into this
classification. VHF radio transmissions do not bend to any
significant degree and generally follow a line of sight path
from the transmitting antenna to the receiving antenna.
Co-channel interference is caused when the receiver lies in
or near the fringe area of two different stations transmitting
on the same frequency. If two broadcasts are of nearly equal
signal strength at the receiving antenna, both stations will
be detected by the receiver either causing one to be heard for
a few seconds or minutes followed by the other or both mixing
and just being garbled.
For the situations just described, moving the radio to
another location can frequently improve reception. For
example, in fringe areas, placing the radio close to a window
on the side of the building from which the broadcast comes
will often substantially improve reception. Sometimes placing
it near any window will work. In practically all situations
described above, the use of a properly matched outside antenna
will improve reception of the broadcast.
The illustrations included on this page describe several
types of antennas and devices that could be used to enhance a
weather radio broadcast. Some general provisions to keep in
mind are, (a) the range and clarity of reception is dependent
upon the antenna height (the higher the better) and its
orientation (toward the desired station), (b) the use of a
sensitive and quality receiver with an antenna assures more
reliable and clearer reception, (c) weather radio transmits a
vertically polarized signal, therefore a vertically polarized
receiving antenna (elements up and down perpendicular to the
ground) that will receive signals in the 130-175 MHz range
will give best reception, (d) at distances up to 30 to 40
miles, a 1/4 wavelength antenna element (18") is suggested;
for distances greater than 40 miles a 1/2 wavelength antenna
(36") should be used.
The simplest antenna to construct is called a 1/2
wavelength folded dipole antenna and is shown as number (1) near the end of this page. The antenna is
constructed from a piece of flat type parallel TV antenna
lead-in. About 1" of insulation is stripped from the two wires
at both ends of a 36" piece of lead-in wire. The ends are
twisted together and soldered. Midway between the ends, one
wire is cut and the insulation stripped back a sufficient
length (1") to attach the leads from a balun. A balun is a
device that matches the type of antenna or lead-in to the
input of the receiver. Once the connections are made the
exposed wires should be taped. A home made balun is shown in
(2) and an inexpensive commercial model is
shown in (3). The finished antenna should be mounted
so the two twisted ends are straight up and down as shown in
(1). It could be attached to an inside window
sill on a window on the side of the building from which the
signal is transmitted; or better, it should be placed outside,
possibly next to the window or some other convenient location
to easily reach the radio in its most desired location. The
lead from the antenna, if it is the parallel flat TV type,
should be twisted once for each foot of lead and extended at a
right angle from the antenna for approximately 18 inches prior
to any vertical run.
Another simple antenna to use in improving the reception of
the broadcast is to connect the radio to an existing outside
TV antenna. This procedure is illustrated in (4). This method is usually very effective
when the TV antenna is constantly pointed in the direction of
the desired weather radio station. Also, this type antenna
will help when another station on the same frequency is
interfering with the desired station (co-channel
interference). The weather radio frequencies are between TV
channels 6 and 7. Therefore, any TV antenna designed for all
VHF TV channel reception will work very well. Even though the
TV antenna is horizontally polarized (elements parallel with
the ground), there is usually enough vertical signal due to
scattering and reflection of the signal that it will
significantly enhance the received signal. A device called a
band separator or splitter (5) is attached to the end of the TV lead
with one output connected to the TV and the other to a balun
(2/3) then to the weather radio.
For serious problems in receiving weather radio broadcasts,
more sophisticated receiving antenna systems will likely be
necessary. When a home made 1/2 wave length antenna may not be
suitable and an outside TV antenna is not available, a
commercially constructed ground plane antenna (6) with an 18" or 36" vertical shaft is
recommended where directionality is unimportant. This type of
radio receives equally well from all directions.
When directionality is important due to a very weak signal
strength, co-channel interference, or the desired weather
radio station being in a different direction from the most
often watched TV station, a specially built antenna (7) or a separate all VHF channel TV antenna
can be attached to an existing TV mast (8) and permanently pointed in the direction
of the desired weather radio station. To further improve the
signal, the antenna should be mounted so the elements of the
antenna used for the weather radio are aligned vertically to
the ground. The lead-in can be combined with the existing TV
lead-in and split (5) once inside the building. It would be
better, however, for TV/weather radio reception if the
lead-ins are brought separately from the antenna to the radio
or TV.
For severe cases of co-channel interference or extremely
weak signal areas, a corner reflector (9) will generally be the only one to provide
suitable reception. The antennas described here are of the
type, which can usually be installed by most people with a
minimum amount of effort, tools, and experience. As a general
rule, it is better to use 50-70 ohm coaxial cable for lead-ins
from the antenna to the radios. This type of cable is far less
likely to pickup interference and will offer less resistance
to the signal picked up at the antenna. For further
information regarding antennas available in the local areas
and specific instructions for connecting such antennas, a
radio dealer or electronic show should be consulted. They can
assist the purchaser to select the best antenna system to
match the specific radio and to solve reception problems.
The costs of the various methods and devices are listed
below and are only estimates of maximum prices, excluding the
cost of labor should professional installation be required.
(1) $7-10, (2) $3, (3) $5, (4) $30, (5) $3, (6) $30, (7) $50, (8) $30, (9) $175.
As a word of caution, extreme care should be exercised when
working with outside antenna systems. Antennas are usually
most stable when mounted along the side of a building then
extended above the roofline. Sloping roof surfaces, ladders,
and roof edges are very dangerous making serious falls
possible. Also, support masts or antennas can easily come in
contact with the above ground electrical lines causing
potentially fatal shock. If there is any doubt about one's
ability to make an outside antenna installation, professional
or experienced help should be obtained.
- back to the top -
|