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) and 0.7 mV/m (57 dB), 
respectively. For all other stations, the F(50,50) field strength along 
the protected contour is 1.0 mV/m (60 dB).
    (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 (&177;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 
(&177;400 kHz and &177;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) Stations in Puerto Rico and the Virgin Islands may submit 
application for short-spaced locations provided the predicted distance 
to their 1 mV/m field strength contour is not extended toward the 1 mV/m 
field strength contour of any short-spaced station.
    (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

[[Page 124]]

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

[[Page 125]]

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:

                                                                        
------------------------------------------------------------------------
                                                                400/600 
              Relation                Co-Channel    200 kHz       kHz   
------------------------------------------------------------------------
A to A..............................      92(57)      49(30)      29(18)
A to B1.............................     119(74)      72(45)      46(29)
A to B..............................     143(89)      96(60)      67(42)
A to C3.............................     119(74)      72(45)      40(25)
A to C2.............................     143(89)      89(55)      53(33)
A to C1.............................    178(111)     111(69)      73(45)
A to C..............................    203(126)     142(88)      93(58)
B1 to B1............................     143(89)      96(60)      48(30)
B1 to B.............................    178(111)     114(71)      69(43)
B1 to C3............................     143(89)      96(60)      48(30)
B1 to C2............................    175(109)     114(71)      55(34)
B1 to C1............................    200(124)     134(83)      75(47)
B1 to C.............................    233(145)    165(103)      95(59)
B to B..............................    211(131)     145(90)      71(44)
B to C3.............................    178(111)     114(70)      69(43)
B to C2.............................    211(131)     145(90)      71(44)
B to C1.............................    241(150)    169(105)      77(48)
B to C..............................    270(168)    195(121)     105(65)
C3 to C3............................     142(88)      89(55)      42(26)
C3 to C2............................    166(103)     106(66)      55(34)
C3 to C1............................    200(124)     133(83)      75(47)
C3 to C.............................    226(140)    165(103)      95(59)
C2 to C2............................    177(110)     117(73)      56(35)
C2 to C1............................    211(131)     144(90)      76(47)
C2 to C.............................    237(147)    176(109)      96(60)
C1 to C1............................    224(139)     158(98)      79(49)
C1 to C.............................    249(155)    188(117)     105(65)
C to C..............................    270(168)    209(130)     (65)
------------------------------------------------------------------------


[54 105 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]