Sec.  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  Sec.  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
    Sec. 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
    Sec. 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  Sec. 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  Sec. 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  Sec. 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  Sec. 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  Sec.  Sec. 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  Sec. 73.684 of this part and using the appropriate F(50,10) chart
   from Figure 9a, 10a, or 10c of  Sec. 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]