A Phase I licensee's service area is defined by the predicted 38 dBu service contour of its authorized base station or fixed station transmitting on frequencies in the 220-221 MHz band at its initially authorized location, or if the station was modified as described in
Rule 90.751, at its modified location. The Phase I licensee's predicted 38 dBu service contour is calculated using the F(50,50) field strength chart for Channels 7-13 in
Rule 73.699 (Fig. 10), with a 9 dB correction factor for antenna height differential, and is based on the authorized effective radiated power (ERP) and antenna height-above-average-terrain of the licensee's base station or fixed station.
Phase I operating areas are overlaid by Phase II geographic areas. Phase II licensees must protect site-licensed stations as outlined in
Rule 90.763.
In March 1997, the Commission restructured the licensing framework that governs the 220 MHz Service. Site-specific licensing, used in the Phase I, was replaced with a geographic-based system in Phase II. Phase II geographic area licensees are permitted to operate within the geographic limits of their EA, REAG, or NWA areas that are identified by their authorization, but they must protect Phase I stations as described in
Rule 90.763.
The geographic areas for the licenses were created based upon Economic Areas (EAs), developed by the Bureau of Economic Analysis of the U.S. Department of Commerce. The Commission developed larger, regional areas called Economic Area Groupings (EAGs). EAGs include groupings of EAs and encompass the sum total of all EAs. Nationwide licenses include all of the EAGs. Three Nationwide licenses (NWA), 30 regional licenses (EAG), and 875 EA licenses were offered in Phase II. A map (
pdf) of 220 MHz geographical areas may be found at the
Auction-Data-Map site. The geographic areas are defined in
Rule 90.7.