§ 74.1235   Power limitations and antenna systems.

   (a) An application for an FM translator station filed by the licensee
   or permittee of the primary station to provide fill-in service within
   the primary station's coverage area will not be accepted for filing if
   it specifies an effective radiated power (ERP) which exceeds 250 watts.

   (b) An application for an FM translator station, other than one for
   fill-in service which is covered in paragraph (a) of this section, will
   not be accepted for filing if it specifies an effective radiated power
   (ERP) which exceeds the maximum ERP (MERP) value determined in
   accordance with this paragraph. The antenna height above average
   terrain (HAAT) shall be determined in accordance with § 73.313(d) of
   this chapter for each of 12 distinct radials, with each radial spaced
   30 degrees apart and with the bearing of the first radial bearing true
   north. Each raidal HAAT value shall be rounded to the nearest meter.
   For each of the 12 radial directions, the MERP is the value
   corresponding to the calculated HAAT in the following tables that is
   appropriate for the location of the translator. For an application
   specifying a nondirectional transmitting antenna, the specified ERP
   must not exceed the smallest of the 12 MERP's. For an application
   specifying a directional transmitting antenna, the ERP in each
   azimuthal direction must not exceed the MERP for the closest of the 12
   radial directions.

   (1) For FM translators located east of the Mississippi River or in Zone
   I-A as described in § 73.205(b) of this chapter:
       Radial HAAT (meters)     Maximum ERP (MERP in watts)
   Less than or equal to 32                             250
   33 to 39                                             170
   40 to 47                                             120
   48 to 57                                              80
   58 to 68                                              55
   69 to 82                                              38
   83 to 96                                              27
   97 to 115                                             19
   116 to 140                                            13
   Greater than or equal to 141                          10

   (2) For FM translators located in all other areas:
       Radial HAAT (meters)     Maximum ERP (MERP in watts)
   Less than or equal to 107                            250
   108 to 118                                           205
   119 to 130                                           170
   131 to 144                                           140
   145 to 157                                           115
   158 to 173                                            92
   174 to 192                                            75
   193 to 212                                            62
   213 to 235                                            50
   236 to 260                                            41
   261 to 285                                            34
   286 to 310                                            28
   311 to 345                                            23
   346 to 380                                            19
   381 to 425                                          15.5
   426 to 480                                            13
   481 to 540                                            11
   Greater than or equal to 541                          10

   (c) The effective radiated power of FM booster stations shall be
   limited such that the predicted service contour of the booster station,
   computed in accordance with § 73.313 paragraphs (a) through (d) of this
   chapter, may not extend beyond the corresponding service contour of the
   primary FM station that the booster rebroadcasts. In no event shall the
   ERP of the booster station exceed 20% of the maximum allowable ERP for
   the primary station's class.

   (d) Applications for FM translator stations located within 320 km of
   the Canadian border will not be accepted if they specify more than 50
   watts effective radiated power in any direction or have a 34 dBu
   interference contour, calculated in accordance with § 74.1204 of this
   part, that exceeds 32 km. FM translator stations located within 320
   kilometers of the Mexican border must be separated from Mexican
   allotments and assignments in accordance with § 73.207(b)(3) of this
   chapter and are limited to a transmitter power output of 10 watts or
   less. For purposes of compliance with that section, FM translators will
   be considered as Class D FM stations.

   (1) Translator stations located within 125 kilometers of the Mexican
   border may operate with an ERP up to 50 watts (0.050 kW) ERP. A booster
   station may not produce a 34 dBu interfering contour in excess of 32 km
   from the transmitter site in the direction of the Mexican border, nor
   may the 60 dBu service contour of the booster station exceed 8.7 km
   from the transmitter site in the direction of the Mexican border.

   (2) Translator stations located between 125 kilometers and 320
   kilometers from the Mexican border may operate with an ERP in excess of
   50 watts, up to the maximum permitted ERP of 250 watts per
   § 74.1235(b)(2). However, in no event shall the location of the 60 dBu
   contour lie within 116.3 km of the Mexican border.

   (3) Applications for translator or booster stations within 320 km of
   the Canadian border may employ an ERP up to a maximum of 250 watts, as
   specified in § 74.1235(a) and (b). The distance to the 34 dBu
   interfering contour may not exceed 60 km in any direction.

   (e) In no event shall a station authorized under this subpart be
   operated with a transmitter power output (TPO) in excess of the
   transmitter certificated rating. A station authorized under this
   subpart for a TPO that is less than its transmitter certificated rating
   shall determine its TPO in accordance with § 73.267 of this chapter and
   its TPO shall not be more than 105 percent of the authorized TPO.

   (f) Composite antennas and antenna arrays may be used where the total
   ERP does not exceed the maximum determined in accordance with
   paragraphs (a), (b) or (c) of this section.

   (g) Either horizontal, vertical, circular or elliptical polarization
   may be used provided that the supplemental vertically polarized ERP
   required for circular or elliptical polarization does not exceed the
   ERP otherwise authorized. Either clockwise or counterclockwise rotation
   may be used. Separate transmitting antennas are permitted if both
   horizontal and vertical polarization is to be provided.

   (h) All applications must comply with § 73.316, paragraphs (d) and (e)
   of this chapter.

   (i) An application that specifies use of a directional antenna must
   comply with § 73.316, paragraphs (c)(1) through (c)(3) of this chapter.
   Prior to issuance of a license, the applicant must: (1) Certify that
   the antenna is mounted in accordance with the specific instructions
   provided by the antenna manufacturer; and (2) certify that the antenna
   is mounted in the proper orientation. In instances where a directional
   antenna is proposed for the purpose of providing protection to another
   facility, a condition may be included in the construction permit
   requiring that before program tests are authorized, a permittee: (1)
   Must submit the results of a complete proof-of-performance to establish
   the horizontal plane radiation patterns for both the horizontally and
   vertically polarized radiation components; and, (2) must certify that
   the relative field strength of neither the measured horizontally nor
   vertically polarized radiation component shall exceed at any azimuth
   the value indicated on the composite radiation pattern authorized by
   the construction permit.

   Note: Existing licensees and permittees that do not furnish data
   sufficient to calculate the contours in conformance with § 74.1204 will
   be assigned protected contours having the following radii:

   Up to 10 watts—1 mile (1.6 km) from transmitter site.

   Up to 100 watts—2 miles (3.2 km) from transmitter site.

   Up to 250 watts—4 miles (6.5 km) from transmitter site.

   (j) FM translator stations authorized prior to June 1, 1991, with
   facilities that do not comply with the ERP limitation of paragraph (a)
   or (b) of this section, as appropriate, may continue to operate,
   provided that operation is in conformance with § 74.1203 regarding
   interference. Applications for major changes in FM translator stations
   must specify facilities that comply with paragraph (a) or (b) of this
   section, as appropriate.

   [ 55 FR 50697 , Dec. 10, 1990, as amended at  56 FR 56170 , Nov. 1, 1991;
    58 FR 42026 , Aug. 6, 1993;  62 FR 51063 , Sept. 30, 1997;  63 FR 33879 ,
   June 22, 1998;  63 FR 36605 , July 7, 1998]

   return arrow Back to Top