§  73.215   Contour protection for short-spaced assignments.

   The Commission will accept applications that specify short-spaced
   antenna locations (locations that do not meet the domestic co-channel
   and adjacent channel minimum distance separation requirements of
   § 73.207); Provided That, such applications propose contour protection,
   as defined in paragraph (a) of this section, with all short-spaced
   assignments, applications and allotments, and meet the other applicable
   requirements of this section. Each application to be processed pursuant
   to this section must specifically request such processing on its face,
   and must include the necessary exhibit to demonstrate that the
   requisite contour protection will be provided. Such applications may be
   granted when the Commission determines that such action would serve the
   public interest, convenience, and necessity.

   (a) Contour protection. Contour protection, for the purpose of this
   section, means that on the same channel and on the first, second and
   third adjacent channels, the predicted interfering contours of the
   proposed station do not overlap the predicted protected contours of
   other short-spaced assignments, applications and allotments, and the
   predicted interfering contours of other short-spaced assignments,
   applications and allotments do not overlap the predicted protected
   contour of the proposed station.

   (1) The protected contours, for the purpose of this section, are
   defined as follows. For all Class B and B1 stations on Channels 221
   through 300 inclusive, the F(50,50) field strengths along the protected
   contours are 0.5 mV/m (54 dBµ) and 0.7 mV/m (57 dBµ), respectively. For
   all other stations, the F(50,50) field strength along the protected
   contour is 1.0 mV/m (60 dBµ).

   (2) The interfering contours, for the purpose of this section, are
   defined as follows. For co-channel stations, the F(50,10) field
   strength along the interfering contour is 20 dB lower than the F(50,50)
   field strength along the protected contour for which overlap is
   prohibited. For first adjacent channel stations (±200 kHz), the
   F(50,10) field strength along the interfering contour is 6 dB lower
   than the F(50,50) field strength along the protected contour for which
   overlap is prohibited. For both second and third adjacent channel
   stations (±400 kHz and ±600 kHz), the F(50,10) field strength along the
   interfering contour is 40 dB higher than the F(50,50) field strength
   along the protected contour for which overlap is prohibited.

   (3) The locations of the protected and interfering contours of the
   proposed station and the other short-spaced assignments, applications
   and allotments must be determined in accordance with the procedures of
   paragraphs (c), (d)(2) and (d)(3) of § 73.313, using data for as many
   radials as necessary to accurately locate the contours.

   (4) Protected and interfering contours (in dBu) for stations in Puerto
   Rico and the U.S. Virgin Islands are as follows:
   Station with interfering contour Station with protected contour
   Class A Class B1 Class B
   Interfering Protected Interfering Protected Interfering Protected
   Co-Channel:
   Class A 46 66 41 61 40 60
   Class B1 43 63 39 59 38 58
   Class B 45 65 41 61 41 61
   1st Adj. Channel:
   Class A 61 67 56 62 59 65
   Class B1 57 63 54 60 54 60
   Class B 62 68 56 62 57 63
   2nd-3rd Adj. Channel:
   Class A 107 67 100 60 104 64
   Class B1 99 59 100 60 104 64
   Class B 94 54 94 54 104 64

   Maximum permitted facilities assumed for each station pursuant to 47
   CFR 73.211(b)(3):

   6 kW ERP/240 meters HAAT—Class A

   25 kW ERP/150 meters HAAT—Class B1

   50 kW ERP/472 meters HAAT—Class B

   (b) Applicants requesting short-spaced assignments pursuant to this
   section must take into account the following factors in demonstrating
   that contour protection is achieved:

   (1) The ERP and antenna HAAT of the proposed station in the direction
   of the contours of other short-spaced assignments, applications and
   allotments. If a directional antenna is proposed, the pattern of that
   antenna must be used to calculate the ERP in particular directions. See
   § 73.316 for additional requirements for directional antennas.

   (2) The ERP and antenna HAAT of other short-spaced assignments,
   applications and allotments in the direction of the contours of the
   proposed station. The ERP and antenna HAATs in the directions of
   concern must be determined as follows:

   (i) For vacant allotments, contours are based on the presumed use, at
   the allotment's reference point, of the maximum ERP that could be
   authorized for the station class of the allotment, and antenna HAATs in
   the directions of concern that would result from a non-directional
   antenna mounted at a standard eight-radial antenna HAAT equal to the
   reference HAAT for the station class of the allotment.

   (ii) For existing stations that were not authorized pursuant to this
   section, including stations with authorized ERP that exceeds the
   maximum ERP permitted by § 73.211 for the standard eight-radial antenna
   HAAT employed, and for applications not requesting authorization
   pursuant to this section, contours are based on the presumed use of the
   maximum ERP for the applicable station class (as specified in § 73.211),
   and the antenna HAATs in the directions of concern that would result
   from a non-directional antenna mounted at a standard eight-radial
   antenna HAAT equal to the reference HAAT for the applicable station
   class, without regard to any other restrictions that may apply (e.g.
   zoning laws, FAA constraints, application of § 73.213).

   (iii) For stations authorized pursuant to this section, except stations
   with authorized ERP that exceeds the maximum ERP permitted by § 73.211
   for the standard eight-radial antenna HAAT employed, contours are based
   on the use of the authorized ERP in the directions of concern, and
   HAATs in the directions of concern derived from the authorized standard
   eight-radial antenna HAAT. For stations with authorized ERP that
   exceeds the maximum ERP permitted by § 73.211 for the standard
   eight-radial antenna HAAT employed, authorized under this section,
   contours are based on the presumed use of the maximum ERP for the
   applicable station class (as specified in § 73.211), and antenna HAATs
   in the directions of concern that would result from a non-directional
   antenna mounted at a standard eight-radial antenna HAAT equal to the
   reference HAAT for the applicable station class, without regard to any
   other restrictions that may apply.

   (iv) For applications containing a request for authorization pursuant
   to this section, except for applications to continue operation with
   authorized ERP that exceeds the maximum ERP permitted by § 73.211 for
   the standard eight-radial antenna HAAT employed, contours are based on
   the use of the proposed ERP in the directions of concern, and antenna
   HAATs in the directions of concern derived from the proposed standard
   eight-radial antenna HAAT. For applications to continue operation with
   an ERP that exceeds the maximum ERP permitted by § 73.211 for the
   standard eight-radial HAAT employed, if processing is requested under
   this section, contours are based on the presumed use of the maximum ERP
   for the applicable station class (as specified in § 73.211), and antenna
   HAATs in the directions of concern that would result from a
   nondirectional antenna mounted at a standard eight-radial antenna HAAT
   equal to the reference HAAT for the applicable station class, without
   regard to any other restrictions that may apply.

   Note to paragraph (b): Applicants are cautioned that the antenna HAAT
   in any particular direction of concern will not usually be the same as
   the standard eight-radial antenna HAAT or the reference HAAT for the
   station class.

   (c) Applications submitted for processing pursuant to this section are
   not required to propose contour protection of any assignment,
   application or allotment for which the minimum distance separation
   requirements of § 73.207 are met, and may, in the directions of those
   assignments, applications and allotments, employ the maximum ERP
   permitted by § 73.211 for the standard eight-radial antenna HAAT
   employed.

   (d) Stations authorized pursuant to this section may be subsequently
   authorized on the basis of compliance with the domestic minimum
   separation distance requirements of § 73.207, upon filing of an FCC Form
   301 or FCC Form 340 (as appropriate) requesting a modification of
   authorization.

   (e) The Commission will not accept applications that specify a
   short-spaced antenna location for which the following minimum distance
   separation requirements, in kilometers (miles), are not met:
   Relation Co-Channel 200 kHz   400/600 kHz
   A to A       92 (57)  49 (30)     25 (16)
   A to B1     119 (74)  72 (45)     42 (26)
   A to B      143 (89)  96 (60)     63 (39)
   A to C3     119 (74)  72 (45)     36 (22)
   A to C2     143 (89)  89 (55)     49 (30)
   A to C1    178 (111) 111 (69)     69 (43)
   A to C0    193 (120) 130 (81)     80 (50)
   A to C     203 (126) 142 (88)     89 (55)
   B1 to B1    143 (89)  96 (60)     44 (27)
   B1 to B    178 (111) 114 (71)     65 (40)
   B1 to C3    143 (89)  96 (60)     44 (27)
   B1 to C2   175 (109) 114 (71)     50 (31)
   B1 to C1   200 (124) 134 (83)     71 (44)
   B1 to C0  0215 (134) 153 (95)     81 (50)
   B1 to C    233 (145) 165 (103)     99 (61)
   B to B     211 (131) 145 (90)     68 (42)
   B to C3    178 (111) 114 (70)     65 (40)
   B to C2    211 (131) 145 (90)     68 (42)
   B to C1    241 (150) 169 (105)     73 (45)
   B to C0    266 (165) 195 (121)     83 (52)
   B to C     268 (163) 195 (121)     99 (61)
   C3 to C3    142 (88)  89 (55)     37 (23)
   C3 to C2   166 (103) 106 (66)     50 (31)
   C3 to C1   200 (124) 133 (83)     70 (43)
   C3to C0    215 (134) 152 (94)     81 (50)
   C3 to C    226 (140) 165 (103)     90 (56)
   C2 to C2   177 (110) 117 (73)     52 (32)
   C2 to C1   211 (131) 144 (90)     73 (45)
   C2 to C0   227 (141) 163 (101)     83 (52)
   C2 to C    237 (147) 176 (109)     96 (61)
   C1 to C1   224 (139) 158 (98)     76 (47)
   C1 to C0   239 (148) 176 (109)     88 (55)
   C1 to C    249 (155) 188 (117)     99 (61)
   C0 to C0   259 (161) 196 (122)     90 (56)
   C0 to C    270 (168) 207 (129     99 (61)
   C to C     270 (168) 209 (130)      99 (61)

   [ 54 FR 9802 , Mar. 8, 1989, as amended at  54 FR 35340 , Aug. 25, 1989;  56 FR 57294 , Nov. 8, 1991;  57 FR 46325 , Oct. 8, 1992;  65 FR 79777 , Dec.
   20, 2000;  66 FR 8149 , Jan. 29, 2001]