Data sources and methods
Every transmitter, frequency, county and SAME code on this site comes from one file the National Weather Service publishes: the NOAA Weather Radio County Coverage Listing. It is reproduced as published, with one exception described below. The few figures the site calculates are listed with their formulas.
Nothing is smoothed, estimated, or filled in from a neighboring transmitter or county. Each publisher below links to the government page the data is taken from.
Data sources
| Dataset | Published by | Coverage | As of | Produces |
|---|---|---|---|---|
| NWR County Coverage Listing | National Weather Service | Every NOAA Weather Radio transmitter in the US and its territories, one row per county or part-county it serves: 1,035 transmitters, 6,633 county rows | Refreshed 2026-10-08. Checked against NOAA's live file every Monday | The station finder, the county pages for each state, a page for every transmitter, the seven frequency pages, and the station counts on NOAA Weather Radio frequencies |
| SAME event codes | National Weather Service | The three-letter event codes in an alert header | Retrieved 2026-08-01 | The event code table on SAME codes |
| FRS and CB service rules | FCC, 47 CFR Part 95, via eCFR | FRS channel frequencies (Subpart B), CB channel 9 and its reserved uses (Subpart D) | Retrieved 2026-08-01 | Channel frequencies on the 3-3-3 radio plan and emergency nets |
About the NOAA listing
NOAA publishes the listing as a JavaScript file, CCL.js, which feeds the county coverage page on weather.gov. Each row is one county served by one transmitter, and carries the county, its state and SAME code, any remark on partial coverage (for example "Eastern"), and the transmitter's callsign, frequency, site name, site state, power in watts, coordinates, operational status and National Weather Service forecast office.
The site regroups those rows two ways. The finder and the state pages group them by county, so a county served by three transmitters lists all three. The station pages group them by transmitter. A station page is filed under the state the transmitter stands in, which can differ from the states of some counties it covers; those counties also appear on their own state's page.
Remarks are shown as NOAA wrote them. Where NOAA marks a county as covered in part, the site says so and does not guess which part.
Where the site departs from NOAA's file
On 2026-10-08, NOAA's live listing gave 11 transmitters a site state that matches none of the counties they serve. WXM59 at State College, for example, is listed as standing in Indiana, while every county it covers is in Pennsylvania. The county rows for all 11 are correct.
For these 11 the site keeps the state that matches the transmitter's own counties. The rule is positional: when NOAA's site state is not the state of any county the transmitter serves, and the state the site already carried is, the site keeps its state. This is the only field, and these are the only records, where the site's copy differs from NOAA's.
| Callsign | Transmitter | NOAA lists the site in | Counties served are in |
|---|---|---|---|
| WXJ41 | Hartford | Alabama | Connecticut |
| WXM42 | Hagerstown | Colorado | Maryland |
| WWH35 | Cooperstown | Connecticut | New York |
| WZ2545 | Joplin | Connecticut | Missouri |
| KIH47 | Hattiesburg | Indiana | Mississippi |
| WXM59 | State College | Indiana | Pennsylvania |
| WXK62 | Waverly | Indiana | Tennessee |
| WXK27 | Austin | Indiana | Texas |
| WWG79 | West Liberty | Indiana | Kentucky |
| WXJ68 | Maricao | Indiana | Puerto Rico |
| WXJ69 | San Juan | Indiana | Puerto Rico |
About transmitter status
Status (normal, degraded, or out of service) is shown exactly as NOAA's listing gave it on the date of the last refresh. It is a snapshot. A transmitter can fail or come back between checks, and failures are most likely during the storms that make you reach for the radio.
In an emergency, confirm your local transmitter's status with your National Weather Service forecast office. Each station page names the office that runs it. Where a county is served by more than one transmitter, the finder lists them all; the second one is your backup.
Calculated figures
Figures not listed here are reproduced as published.
| Figure | Formula | Inputs | Limits |
|---|---|---|---|
| Distance to the nearest transmitters | great-circle distance, earth radius 3,959 miles |
Your device's reported location; transmitter coordinates from the NOAA listing | Straight-line distance. The nearest transmitter is not always the strongest at your location: terrain and antenna height decide that. The calculation runs in your browser, and your location is not sent anywhere |
| Transmitters per frequency | count of transmitters in the NOAA listing on each frequency |
NWR County Coverage Listing, refreshed 2026-10-08 | Changes when NOAA adds, retires, or retunes a transmitter |
| Radio horizon | 1.415 x square root of antenna height in feet (statute miles; 1.228 for nautical miles, 2.277 for kilometers) |
The antenna height you enter on VHF range | A 4/3-earth rule of thumb for open ground or water. Terrain, buildings and trees only shorten it; atmospheric ducting occasionally extends it |
Verification
Every Monday an automated check downloads NOAA's live listing and compares it with the site's copy: transmitters added or removed, status changes, frequency changes, and counties added or dropped. Differences are reviewed and applied by refreshing the site's copy from NOAA's file, after which every finder file, state page and station page is rebuilt from the new copy.
This confirms that the site matches NOAA's file as downloaded. It does not check that NOAA's file is correct, current, or complete, and we make no promise that it is.
Licensing
The NOAA listing, the National Weather Service pages, and the Code of Federal Regulations are works of the U.S. government and are in the public domain. The site takes them directly from weather.gov and ecfr.gov, so no figure here depends on a commercial data provider's terms.
Some links elsewhere on this site earn a commission. See the affiliate disclosure. Commercial relationships have no effect on any transmitter, frequency, code or status shown.
This site is independent. It is not affiliated with, endorsed by, or approved by NOAA, the National Weather Service, or the FCC.
Corrections
Think a transmitter, frequency or code is wrong? Email contact@emergencyradio.org with the callsign or the county. We check it against NOAA's current file and correct our copy if it differs. If NOAA's file itself is wrong, the forecast office that runs the transmitter is the one that can fix it.
NOAA data last refreshed 2026-10-08.