Mexican Border Zone Spacing

US FM station located within 320 km of the Mexican border has to meet Mexican border zone spacing requirements.

The table below lists spacing requirements for US FM stations with respect to Mexican stations based on FCC 73.207 rule.

Mexican Border Zone Spacing
Relation Co-Channel (Same Frequency) 200 kHz (1st Adjacent Channel) 400 or 600 kHz (2nd or 3rd Adjacent Channel)
A - A 100 km 61 km 25 km
A - AA 111 km 68 km 31 km
A - B1 138 km 88 km 48 km
A - B 163 km 105 km 65 km
A - C1 196 km 129 km 74 km
A - C 210 km 161 km 94 km
AA - AA 115 km 72 km 31 km
AA - B1 143 km 96 km 48 km
AA - B 178 km 125 km 69 km
AA - C1 200 km 133 km 75 km
AA - C 226 km 165 km 95 km
B1 - B1 175 km 114 km 50 km
B1 - B 211 km 145 km 71 km
B1 - B1 175 km 114 km 50 km
B1 - C1 233 km 161 km 77 km
B1 - C 259 km 193 km 96 km
B - B 237 km 164 km 65 km
B - C1 270 km 195 km 79 km
B - C 270 km 215 km 98 km
C1 - C1 245 km 177 km 82 km
C1 - C 270 km 209 km 102 km
C - C 290 km 228 km 105 km


Note

  • US or Mexican Class A stations which have been notified internationally as Class A are limited to a maximum of 3.0 kW ERP at 100 meters HAAT.
  • US or Mexican Class A stations which have been notified internationally as Class AA are limited to a maximum of 6.0 kW at 100 meters HAAT.
  • US Class C3 assignments or allotments are considered Class B1.
  • US Class C2 assignments or allotments are considered Class B.
  • Class C1 assignments or allotments assume maximum facilities of 100 kW ERP at 300 meters HAAT. However, US Class C1 stations may not, in any event, exceed the domestic US limit of 100 kW ERP at 299 meters HAAT.
  • US Class C0 assignments or allotments are considered Class C.

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