NOAA Weather Radio
http://en.wikipedia.org/wiki/NOAA_Weather_Radio
NOAA Weather Radio (NWR) is a nationwide network of radio stations broadcasting
continuous weather information directly from a nearby National Weather Service office [1].
NWR broadcasts National Weather Service warnings, watches, forecasts and other hazard
information 24 hours a day.
Working with the Federal Communication Commission's (FCC) Emergency Alert System ,
NWR is an "All Hazards" radio network, making it your single source for comprehensive
weather and emergency information. In conjunction with Federal, State, and Local Emergency
Managers and other public officials, NWR also broadcasts warning and post-event
information for all types of hazards – including natural (such as earthquakes or avalanches),
environmental (such as chemical releases or oil spills), and public safety (such as AMBER
alerts or 911 Telephone outages).
Operations
Known as the "Voice of NOAA's National Weather Service," NWR is provided as a public
service by the National Oceanic and Atmospheric Administration (NOAA), part of the
Department of Commerce. NWR includes more than 940 transmitters[2] , covering all 50
states, adjacent coastal waters, Puerto Rico, the U.S. Virgin Islands, and the U.S. Pacific
Territories. NWR requires a special radio receiver or scanner capable of picking up the signal.
The radio service, available over much of North America, transmits weather warnings and
forecasts 24 hours a day. Hundreds of stations are operated in the U.S. (where it is more
commonly called NOAA Weather Radio (NWR)) by the National Weather Service of NOAA,
and in Canada by the Meteorological Service of Canada, under Environment Canada. Each
radio station is programmed from a local or regional NWS or MSC office. One station is also
available in Bermuda, operated by the Bermuda Weather Service.
Most stations broadcast on a special VHF frequency band at 162 MHz, which has seven
narrowband FM channels. The original frequency was 162.550, with 162.400 and 162.475
being added later. In recent years, the proliferation of stations meant to make sure everyone
has access to warnings has pushed that number to seven, now including the "intermediate"
channels of 162.425, 162.450, 162.500, and 162.525 MHz. These channels (often numbered
in that order) are receivable on special weather radio receivers, available across both countries
by mail-order and at some retailers such as Radio Shack, on most marine VHF radio
transceivers, and on scanners. In addition, many consumer electronics, such as two-way
radios, are now being sold with the ability to receive weather radio broadcasts. Some stations
in Canada also broadcast on regular FM and AM broadcast frequencies.
When a weather warning is issued for the area which a station covers, certain weather radios
are designed to turn on or sound an alarm upon detection of a 1050 Hz tone, issued for ten
seconds immediately before the warning message. In the U.S., newer radios can instead detect
a digital-over-audio protocol called Specific Area Message Encoding or SAME, which allows
the radio to limit alarms to only certain warnings, and only to the actual section of the
broadcast area which the listener is located. (This system was later adopted by the Emergency
Alert System -- the replacement for the earlier Emergency Broadcast System and even earlier
CONELRAD) now required by the FCC for broadcast stations.) In Canada, many stations
operate Weather-copy, which is a higher-speed version that can actually transmit entire text
forecasts and warnings, but is not designed for alerting. This system has been
decommissioned in 2003 because of new technologies such as the internet and satellite.
Example NOAA weather radio coverage for part of Michigan. The bulk of programming
however is still in regular voice rather than digital, with a forecaster recording each message
once and a system having it repeat in a loop. In the U.S., the NWS has now installed a console
replacement system (CRS) which uses a synthesized voice to read text announcements. The
voices have recently been upgraded with new software that gives a much more realistic and
pleasant male (named "Tom", who reads the public forecast) or female voice (named "Donna",
who reads the marine forecast and the hourly weather roundup), and also allows intonation so
that the tone of voice changes with the urgency of the message being read. They supplanted a
more primitive male voice called "NOAA's Perfect Paul" from DECTalk System & TripleTalk
which had been nicknamed "Igor", "Sven", and "Arnold", among others, for its mechanically
awkward pronunciation and intonation (another voice, "Huge Harry" was also used). "Paul"
and "Harry" can still occasionally be heard on some stations, for example giving station
identification.
Many stations also broadcast in other local languages, including both French and English in
Ottawa/Gatineau, Montréal, and the city of Québec; French only in other parts of the province
of Québec, and synthesized in both English and Spanish in Puerto Rico.
External links
U.S. NOAA/NWS Weatheradio page www.nws.noaa.gov/nwr
Canada EC/MSC Weatheradio page http://www.msc.ec.gc.ca/msb/weatheradio//index_e.cfm
Bermuda Weather Service www.bermudaweather.bm/bws/
http://www.weatherradio.info
Emergency Alert System
http://en.wikipedia.org/wiki/Emergency_Alert_System
The Emergency Alert System (EAS), is a national system in the U.S. put into place in 1997,
superseding the Emergency Broadcast System and administered by the Federal
Communications Commission (FCC). The EAS covers both radio and television (including
low-power stations), and cable television companies.
EAS messages are handled by specialized equipment called EAS encoder-decoders, or endecs.
The decoder component receives and interprets EAS messages from at least two
state-assigned stations, and the encoder component transmits relayed messages. Low-power
stations are only required to have the decoder components, but all other stations must have
both decoder and encoder components.
Technical concept
In the EAS system, messages are originated in four parts. The first part is the SAME header
code, the most critical part of the EAS design. It is repeated three times, so that decoders can
pick "best two out of three" for each byte, thereby eliminating most errors which can cause an
activation to fail. The header code contains information about who originated the alert
(President, state or local authorities, the National Weather Service, or the broadcaster), what
the event is (tornado, flood, nuclear), the areas affected (up to 32 counties or states), how long
the alert is valid for, the exact UTC time it was issued, and the identification of the station or
other entity. (See SAME for a complete breakdown of the header.)
Each station must have installed an EAS decoder which then interprets these data bursts. Two
of the three bursts must be found to be identical by the decoder for the message to be valid.
The decoder then decides, based on its pre-programming, whether to ignore the message as
not pertaining to the local area, or whether to relay it on the air. All EAN and EAT messages
must be relayed immediately, and all required weekly and monthly tests (RWT and RMT)
within 60 (formerly 15) minutes. For reliability, every station must monitor at least two other
source stations, one of which must be designated a local primary.
The SAME header bursts are followed by an alert tone, lasting between eight and 25 seconds
depending on the originating station, that carries no information. The tone, a combination of
853 Hz and 960 Hz sine wave tones, is the same combination of two tones that the old
Emergency Broadcast System used as its attention signal. Like the old EBS, this tone is in
turn followed by a voice message giving details of the alert.
The message is ended by three bursts of the AFSK "EOM", or end of message, which is the
text NNNN, preceded each time by the binary 10101011 calibration.
All EAS equipment must be tested weekly. The RWT, or required weekly test, consists only of
the three AFSK header bursts and the three AFSK EOM bursts with no voice, and are
essentially internal tests of the system components. Required monthly tests (RMT) are
transmitted with all four parts, with the voice (and text on TV) stating that it is only a test. The
RMT must be transmitted in the daytime and at night in alternating months.
The number of events in the national system has recently grown by several increments, and is
now forty-nine events. At first, they were almost all weather events with only one to three
possible categories for civil emergencies, but several classes of non-weather emergencies
have now been added. In most states, the AMBER Alert System, for child abduction
emergencies, has now been added as well.
Stations are required by law to keep full logs of all received and transmitted EAS messages,
usually accomplished by a small receipt printer in the endec unit. Logs may also be kept
electronically inside the unit, as long as there is access to an external printer, sometimes via
transfer to a personal computer.
In 2004, the FCC issued a Notice of Proposed Rulemaking seeking comment on whether EAS
in its present form is the most effective mechanism for warning the American public of an
emergency and, if not, on how EAS can be improved.
EAS for consumers
EAS is designed to be useful for the entire public, not just those with SAME-capable
equipment. However, several consumer-level radios do exist, especially weather radio
receivers, which are available to the public through both mail-order and retailers like Radio
Shack, Circuit City, Best Buy, and several others. Other specialty receivers for FM radio are
available only through mail-order, or in some places from federal, state, or local governments,
especially where there is a potential hazard nearby such as a nuclear plant or chemical factory.
These radios come pre-tuned to a station in each area that has agreed to provide this service to
local emergency management officials and agencies, often with a direct link back to the
plant's safety system or control room for instant activation should an evacuation or other
emergency arise.
The ability to narrow messages down so that only the actual area in danger is alerted is
extremely helpful in preventing false warnings, which was previously a major tune-out factor.
Instead of sounding for all warnings within a station's area, SAME-decoder radios now sound
only for the counties they are programmed for. When the alarm sounds, anyone with the radio
knows that the danger is nearby and protective action should be taken. For this reason, the
goal of the National Weather Service is that each home should have both a smoke detector and
a SAME weather radio.
Incidents
Several state officials including New York Governor George Pataki, former New York City
Mayor Rudolph W. Giuliani and U.S. Congressmen and Senators have questioned members of
the FCC on why the Emergency Alert System was not implemented nationwide on radio and
television stations during the September 11, 2001 Terrorist Attacks where official government
information is/was supposed to be distributed in place of local/network programming or
newscasts. The EAS was to have issued such messages that the United States was under attack,
but no warning broadcast was issued...even in New York City.
On February 1, 2005 at 2:10pm Eastern Standard Time an employee within the Connecticut
Office of Emergency Management inadvertently activated an EAS message over radio and
television stations telling residents to evacuate the state immediately. At 3:45pm officials at
the OEM announced that the activation and broadcast of the Emergency Alert System was in
error due to the fact that the button used to conduct weekly EAS tests is located next to a
button that is used to issue an emergency alert to evacuate the state.