FrequentlyAskedQuestions

How do I search for a station by Call Letters?
Find and click on the type-in text box labeled "Type in a station's call letters and click GO", and begin typing in the call letters. The application will suggest call letter combinations that match your typing.
At any time, click on one of the suggestions to choose it, then click the GO icon.
The application will display that station and its coverage contours.
To see the demographic data for that station's coverage, click on its red dot. An information balloon will appear on the map, and in a few moments, the demographic data will appear in the table below.     TOP

How do I see the stations in a particular metropolitan area?
Find the pull-down box labeled Quickviews, and select from one of almost 300 U.S. Metropolitan Areas. Once selected, the application will display that metro area and all commercial and public TV stations.     TOP

How do I see the coverage pattern for a station?
Once you have identified the station or its metropolitan area, a scrollable area labeled "Viewable public television stations" will appear, displaying information about all Public TV stations seen within the map.
Click the check box labeled "Station Coverage Overlay" and that station's three-fieldstrength coverage pattern will be displayed on the map.
Click on the station's red dot to display a balloon popup with relevant information and display its demographic data in the demographic table.     TOP

Can I see more than one station's coverage patterns?
Yes! You may click as many station "Station Coverage Overlay" checkboxes as you wish. As each selected coverage pattern is displayed, it is overlayed on top of the previous pattern.
If you are having trouble discerning overlapping coverage, try unselecting and reselecting a station's coverage so its pattern is overlayed on top of the other station's pattern.     TOP

What do the contour colors mean?
This study calculates three Field Strength Contours, measured in dBµ. The yellow represents the strongest Field Strength, the green represents a weaker Field Strength, and the red represents the least Field Strength contour.
Because DTV channels have different power allocation based on their frequency, there are three different sets of DTV Field Strength contours.
Because NTSC signals, such as with low power TV and translators, have different power allocation based on their frequency, there are three different sets of NTSC Field Strength contours.
To reduce confusion, a color legend of the selected station's contours is displayed between its call letters and the demographic tables.     TOP

How do I see demographic data on a station's coverage?
After you have selected the station by clicking on its red dot, the table below the map will be populated with demographic data, if available.
The total population and median household income are displayed for three census periods, and a pull-down Select... box offers over 100 other demographic data elements that can be viewed.     TOP

For what area does a station's demographic area cover?
The demographic data displayed is a total of the station's coverage area; that is, everywhere a station's signal is seen on the coverage map, that population has been accounted.     TOP

The contour legend values that popped up don't match the main contour legend for the station's channel. Why?
We have seen some discrepancy in a couple of instances between the published channel number and the calculated contour values. That is, a station's popup balloon may show it is on channel 51, but the contour values show it is a DTV station between channels 7-13.
At the time NPRLabs generated the coverage patterns, we used FCC regulatory data from March 12, 2009---before the mandated DTV conversion---and some stations were broadcasting in NTSC and DTV. The NTSC channel was the 'primary' and was included in our data.
If you see errors, please bring it to our attention by writing to Mike Starling, Executive Director, NPRLabs ( mstarling at nprlabs dot org ).     TOP

The coverage pattern is displayed for one station, yet the demographic data displayed is for a different station. What's going on?
This is by design; you can examine the coverage patterns of none, one or many stations, and still examine the demographic data of an entirely different station.     TOP

Why don't coverage patterns and demographic data appear when I select a commercial station, or click on the gray dots on the map?
This application was created and paid for by Public Television, so no contour maps or demographic data has been created for commercial stations (those are the "gray dots" on the map).
However, clicking on a gray dot will pop up the basic information balloon, which includes call letters, channel, station class, and the docket number that can be searched for on the FCC web site. The city of license is displayed with the call letters, near the [empty] demographic data table.     TOP

How do I click on co-located stations?
This has been difficult to solve, and we offer this workaround:
Using the zoom button near the top left of the Google Map , (the "+"), zoom in on the map to attempt to resolve the different stations' dots. Then click on the desired station. The commercial stations dots are smaller than the public TV stations, making it easier to click on the Public TV station's 'dot'.     TOP

SOURCE

The source data for the Regulatory information was drawn from the Federal Communication Commission's Index of Media Bureau CDBS Public Database Files http://www.fcc.gov/mb/databases/cdbs/ from March 12, 2009.
The coverage maps were generated at NPRLabs from terrain data using the irregular terrain model, the same point-to-point model used by the FCC.

The database contains over 750,000 demographic data points and over 32,000 regulatory information data points. Within the regulatory information table, some stations have multiple CP and LIC entries, of which we display the most recent docket.

ABSTRACT

NPR Labs, in collaboration with PBS Technology and Operations, requested funds from the Public Telecommunications Facilities Program ( PTFP ) to research, prepare and distribute a comprehensive, nationwide study of public television digital coverage, necessitated by the change in the service area of many public television stations due to the shut off of analog signals in February 2009.

The DTV transition caused many stations to change their channels and operate under different broadcast characteristics that will change their service area. This study helps users understand the implications of their new service area, including identifying under-served areas of the country, changes in service area and population, and changes in cable carriage. This study includes TV translators---identified by the study CPB is sponsoring---to create a verified list of TV translators of all CPB-qualified public TV licensees.

The study performed an in-depth analysis of the new market coverage for each public television station that can guide station-planning efforts to improve coverage and services. In addition, the study tabulated demographic coverage for minorities and specialized audiences, such as citizens with visual or hearing impairment. To make the study accessible to the largest range of potential users, the results are presented in this interactive Web-based system.
The study included collaboration with public television licensees, organizations and stakeholders.
Unique features are:
• Downloadable data - In addition to printed compendiums, detailed mapping and
demographic data will be available to all PTFP-eligible entities for download on the Web;
• Configurable coverage maps - Levels of labeling and detail will be selectable via the
Internet gateway to provide enhanced illustrations and analysis;
• Historical projections - Inclusion of key demographic data from a previous U.S. Census
to identify historical shifts in population served by public television; and
• Ongoing support - All data will be maintained continuously for one year (renewable)
following initial release.

CORRECTIONS

Although NPRLabs has carefully constructed this online viewing application and checked the source data for completeness, as with any highly technical endeavor, you may find inaccuracies.
Please let us know by writing to Mike Starling, Executive Director, NPRLabs
( mstarling at nprlabs dot org )