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Frequently Asked Questions about Radio-Locator Coverage Maps

1. These maps are cool, how are they drawn?

These maps are drawn using engineering data from the FCC. The coverage pattern for each FM station is calculated using the effective radiated power (ERP) of the station and the antenna height above average terrain (HAAT). The HAAT is calculated in all directions based upon the average ground elevation between 1.5 and 10 miles from the station in each direction.

The coverage pattern for each AM station is based on the standard groundwave field strength pattern, the frequency of the station, and the ground conductivity of the local area.

2. What do the red, purple, and blue lines mean?

The red, purple, and blue lines correspond to the "local", "distant", and "fringe" coverage areas of each radio station:

* Local Coverage: Within this area, you should be able to receive the radio station on almost any radio with moderately good to very good reception.

* Distant Coverage: Within this area, the signal of the radio station may be weak unless you have a good car radio or a good stereo with a good antenna. You may not be able to receive the station at all on walkmans or other portable radios.

* Fringe Coverage: Within this area, the station's signal will be very weak. You may be able to receive this station if you have a very good radio with a good antenna, but it's possible that interference from other stations may prevent you from picking up these stations at all.

3. What criteria do you use to define the "local", "distant" and "fringe" coverage areas?

The "local", "distant" and "fringe" lines on the FM maps correspond to the predicted 60, 50, and 40 dBu field strength contours respectively.