Do Coverage Maps Need To Be Accurate?


Are there any  FCC requirements in relation to coverage maps used within sales literature? This query stems from stations using self-created maps suggesting their coverage area may be greater than what the FCC might recognize within accepted contour maps. But is there anything that governs acceptable sources and/or misrepresentation in the matter?

“The accuracy of radio station coverage maps given to advertisers, many, many years ago, used to be the subject of a strict FCC policy. In 1975, the FCC stated that “[f]ull disclosure and candor are expected of the licensee in his dealings with potential advertisers — with regard to the station’s coverage area, power and other matters relating to audience potential. Inaccurate or misleading statements to induce the purchase of advertising time must be avoided.”  The FCC back then granted short-term license renewals and put stations into hearings for allegations that a licensee misrepresented its coverage contours to advertisers.

In 1983, the FCC gave it all up, declaring in a policy statement that it would no longer concern itself with ratings distortion and coverage map issues.  So, the short answer is that today there are no FCC requirements for coverage maps used in sales literature.

That being said, it is worth noting that a coverage map drawn using the FCC’s predicted method of contour calculation is often an abysmal way to show actual broadcast station coverage.  AM stations that use the 0.5 mV/m contour usually overstate coverage.  FM stations that use the FCC service area contour of 60 dBu (57 dBu for Class B1, and 54 dBu for Class B, stations), particularly in hilly terrain, often understate coverage in certain directions.  Those stations that use non-FCC recognized contours such as a low 0.1 mV/m contour for AM stations, and a 50 dBu or lower signal for FM stations, severely overstate their actual coverage.

For more accurate FM coverage maps, particularly for FM stations in anything other than flat terrain, stations might want to consider a coverage map drawn using an alternate prediction method such as Longley-Rice.  FM coverage maps drawn using Longley-Rice calculations often more accurately show real world coverage, and can be attractive maps with different signal levels represented in different shades of color.

Even though the FCC does not still regulate coverage maps used in sales literature, it neither serves stations nor advertisers to have coverage maps based upon inaccurate parameters.  Consider asking your favorite FCC consulting engineer about a more accurate coverage map using alternate prediction methodology, even though rather than the FCC, it is now the marketplace  that regulates this aspect of radio station operations.


Please enter your comment!
Please enter your name here