§  73.613   Protection of Class A TV stations.

   (a) An application for a new TV broadcast station or for changes in the
   operating facilities of an existing TV broadcast station will not be
   accepted for filing if it fails to comply with the requirements
   specified in this section.

   Note to §  73.613( a ): Licensees and permittees of TV broadcast
   stations that were authorized on November 29, 1999 (and applicants for
   new TV stations that had been cut-off without competing applications or
   that were the winning bidder in a TV broadcast station auction as of
   that date, or that were the proposed remaining applicant in a group of
   mutually exclusive applications for which a settlement agreement was on
   file as of that date) may continue to operate with facilities that do
   not protect Class A TV stations. Applications filed on or before
   November 29, 1999 for a change in the operating facilities of such
   stations also are not required to protect Class A TV stations under the
   provisions of this section.

   (b) Due to the frequency spacing which exists between TV channels 4 and
   5, between channels 6 and 7, and between channels 13 and 14,
   first-adjacent channel protection standards shall not be applicable to
   these pairs of channels. Some interference protection requirements of
   this section only apply to stations transmitting on the UHF TV channels
   14 through 51 (See §  73.603(a) of this part).

   (c) A UHF TV broadcast station application will not be accepted if it
   specifies a site less than 100 kilometers from the transmitter site of
   a UHF Class A TV station operating on a channel which is the seventh
   channel above the requested channel. Compliance with this requirement
   shall be determined based on a distance computation rounded to the
   nearest kilometer.

   (d) A UHF TV broadcast station application will not be accepted if it
   specifies a site less than 32 kilometers from the transmitter site of a
   UHF Class A TV station that is authorized an effective radiated power
   of more than 50 kilowatts and operating on a channel which is the
   second, third, or fourth channel above or below the requested channel.
   Compliance with this requirement shall be determined based on a
   distance computation rounded to the nearest kilometer.

   (e) In cases where a TV broadcast station has been authorized
   facilities that do not meet the distance separation requirements of
   this section, an application to modify such a station's facilities will
   not be accepted if it decreases that separation.

   (f) New interference must not be caused to Class A TV stations
   authorized pursuant to Subpart J of this part, within the protected
   contour defined in §  73.6010 of this part. For this prediction, the TV
   broadcast station field strength is calculated from the proposed
   effective radiated power and the antenna height above average terrain
   in pertinent directions using the methods in §  73.684 of this part.

   (1) For co-channel protection, the field strength is calculated using
   the appropriate F(50,10) chart from Figure 9a, 10a, or 10c of §  73.699
   of this part.

   (2) For TV broadcast stations that do not specify the same channel as
   the Class A TV station to be protected, the field strength is
   calculated using the appropriate F(50,50) chart from Figure 9, 10, or
   10b of §  73.699 of this part.

   (g) A TV broadcast station application will not be accepted if the
   ratio in dB of its field strength to that of the Class A TV station at
   the Class A TV station's protected contour fails to meet the following:

   (1) -45 dB for co-channel operations where the Class A TV station does
   not specify an offset carrier frequency or where the TV broadcast and
   Class A TV stations do not specify different offset carrier frequencies
   (zero, plus or minus) or -28 dB for offset carrier frequency operation
   where the TV broadcast and Class A TV stations specify different offset
   carrier frequencies.

   (2) 6 dB when the protected Class A TV station operates on a VHF
   channel that is one channel above the requested channel.

   (3) 12 dB when the protected Class A TV station operates on a VHF
   channel that is one channel below the requested channel.

   (4) 15 dB when the protected Class A TV station operates on a UHF
   channel that is one channel above or below the requested channel.

   (5) 23 dB when the protected Class A TV station operates on a UHF
   channel that is fourteen channels below the requested channel.

   (6) 6 dB when the protected Class A TV station operates on a UHF
   channel that is fifteen channels below the requested channel.

   (h) New interference must not be caused to digital Class A TV stations
   authorized pursuant to Subpart J of this part, within the protected
   contour defined in §  73.6010 of this part. A TV broadcast station
   application will not be accepted if the ratio in dB of the field
   strength of the digital Class A TV station at the digital Class A TV
   station's protected contour to the field strength resulting from the
   facilities proposed in the TV broadcast station application fails to
   meet the D/U signal ratios for "analog TV-into-DTV" specified in
   § §  73.623(c)(2) and 73.623(c)(3) of this part. For digital Class A TV
   station protection, the TV broadcast station field strength is
   calculated from the proposed effective radiated power and the antenna
   height above average terrain in pertinent directions using the methods
   in §  73.684 of this part and using the appropriate F(50,10) chart from
   Figure 9a, 10a, or 10c of §  73.699 of this part.

   (i) In cases where a TV broadcast station has been authorized
   facilities that do not meet the interference protection requirements of
   this section, an application to modify such a station's facilities will
   not be accepted if it is predicted to cause new interference within the
   protected contour of the Class A TV or digital Class A TV station.

   (j) In support of a request for waiver of the interference protection
   requirements of this section, an applicant for a TV broadcast station
   may make full use of terrain shielding and Longley-Rice terrain
   dependent propagation methods to demonstrate that the proposed facility
   would not be likely to cause interference to Class A TV stations.
   Guidance on using the Longely-Rice methodology is provided in OET
   Bulletin No. 69, which is available through the Internet at
   http://www.fcc.gov/oet/info/documents/bulletins/#69.

   [ 65 FR 3001 , May 10, 2000]

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