Sec.  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  Sec. 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 dB µ) and 0.7 mV/m (57 dB µ), respectively. For all other stations,
   the F(50,50) field strength along the protected contour is 1.0 mV/m (60
   dB µ).

   (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  Sec. 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  Sec. 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  Sec. 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  Sec. 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  Sec. 73.213).

   (iii) For stations authorized pursuant to this section, except stations with
   authorized ERP that exceeds the maximum ERP permitted by  Sec. 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  Sec. 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  Sec. 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  Sec. 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  Sec. 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  Sec. 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  Sec. 73.207
   are met, and may, in the directions of those assignments, applications and
   allotments, employ the maximum ERP permitted by  Sec. 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  Sec. 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]