Sec. 73.211  Power and antenna height requirements.

    (a) Minimum requirements. (1) Except as provided in paragraphs 
(a)(3) and (b)(2) of this section, FM stations must operate with a 
minimum effective radiated power (ERP) as follows:
    (i) The minimum ERP for Class A stations is 0.1 kW.
    (ii) The ERP for Class B1 stations must exceed 6 kW.
    (iii) The ERP for Class B stations must exceed 25 kW.
    (iv) The ERP for Class C3 stations must exceed 6 kW.
    (v) The ERP for Class C2 stations must exceed 25 kW.
    (vi) The ERP for Class C1 stations must exceed 50 kW.
    (vii) The minimum ERP for Class C stations is 100 kW.
    (2) Class C stations must have an antenna height above average 
terrain (HAAT) of at least 300 meters (984 feet). No minimum HAAT is 
specified for Classes A, B1, B, C3, C2, or C1 stations.
    (3) Stations of any class except Class A may have an ERP less than 
that specified in paragraph (a)(1) of this section, provided that the 
reference distance, determined in accordance with paragraph (b)(1)(i) of 
this section, exceeds the distance to the class contour for the next 
lower class. Class A stations may have an ERP less than 100 watts 
provided that the reference distance, determined in accordance with

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paragraph (b)(1)(i) of this section, equals or exceeds 6 kilometers.
    (b) Maximum limits. (1) Except for stations located in Puerto Rico 
or the Virgin Islands, the maximum ERP in any direction, reference HAAT, 
and distance to the class contour for each FM station class are listed 
below:

                                                                        
------------------------------------------------------------------------
                                                                 Class  
                                                  Reference     contour 
   Station class             Maximum ERP           HAAT in     distance 
                                                    meters        in    
                                                    (ft.)     kilometers
------------------------------------------------------------------------
A..................  6kW (7.8 dBk).............    100 (328)          28
B1.................  25kW (14.0 dBk)...........    100 (328)          39
B..................  50kW (17.0 dBk)...........    150 (492)          52
C3.................  25kW (14.0 dBk)...........    100 (328)          39
C2.................  50kW (17.0 dBk)...........    150 (492)          52
C1.................  100kW (20.0 dBk)..........    299 (981)          72
C..................  100kW (20.0 dBk)..........   600 (1968)          92
------------------------------------------------------------------------

    (i) The reference distance of a station is obtained by finding the 
predicted distance to the 1mV/m contour using Figure 1 of Sec. 73.333 
and then rounding to the nearest kilometer. Antenna HAAT is determined 
using the procedure in Sec. 73.313. If the HAAT so determined is less 
than 30 meters (100 feet), a HAAT of 30 meters must be used when finding 
the predicted distance to the 1 mV/m contour.
    (ii) If a station's ERP is equal to the maximum for its class, its 
antenna HAAT must not exceed the reference HAAT, regardless of the 
reference distance. For example, a Class A station operating with 6 kW 
ERP may have an antenna HAAT of 100 meters, but not 101 meters, even 
though the reference distance is 28 km in both cases.
    (iii) Except as provided in paragraph (b)(3) of this section, no 
station will be authorized in Zone I or I-A with an ERP equal to 50 kW 
and a HAAT exceeding 150 meters. No station will be authorized in Zone 
II with an ERP equal to 100 kW and a HAAT exceeding 600 meters.
    (2) If a station has an antenna HAAT greater than the reference HAAT 
for its class, its ERP must be lower than the class maximum such that 
the reference distance does not exceed the class contour distance. If 
the antenna HAAT is so great that the station's ERP must be lower than 
the minimum ERP for its class (specified in paragraphs (a)(1) and (a)(3) 
of this section), that lower ERP will become the minimum for that 
station.
    (3) For stations located in Puerto Rico or the Virgin Islands, the 
maximum ERP in any direction, reference HAAT, and distance to the class 
contour for each FM station class are listed below:

                                                                        
------------------------------------------------------------------------
                                                                 Class  
                                                  Reference     contour 
   Station class             Maximum ERP           HAAT in     distance 
                                                    meters        in    
                                                    (ft.)     kilometers
------------------------------------------------------------------------
A..................  6kW (7.8 dBk).............    240 (787)          42
B1.................  25kW (14.0 dBk)...........    150 (492)          46
B..................  50kW (17.0 dBk)...........   472 (1549)          78
------------------------------------------------------------------------

    (c) Existing stations. Stations authorized prior to March 1, 1984 
that do not conform to the requirements of this section may continue to 
operate as authorized. Stations operating with facilities in excess of 
those specified in paragraph (b) of this section may not increase their 
effective radiated powers or extend their 1 mV/m field strength contour 
beyond the location permitted by their present authorizations. The 
provisions of this section will not apply to applications to increase 
facilities for those stations operating with less than the minimum power 
specified in paragraph (a) of this section.

[ 53 FR 17042 , May 13, 1988, as amended at  54 FR 16367 , Apr. 24, 1989;  54 FR 19374 , May 5, 1989;  54 FR 35339 , Aug. 25, 1989]