§  73.99   Presunrise service authorization (PSRA) and postsunset service
authorization (PSSA).

   (a) To provide maximum uniformity in early morning operation compatible
   with interference considerations, and to provide for additional service
   during early evening hours for Class D stations, provisions are made
   for presunrise service and postsunset service. The permissible power
   for presunrise or postsunset service authorizations shall not exceed
   500 watts, or the authorized daytime or critical hours power (whichever
   is less). Calculation of the permissible power shall consider only
   co-channel stations for interference protection purposes.

   (b) Presunrise service authorizations (PSRA) permit:

   (1) Class D stations operating on Mexican, Bahamian, and Canadian
   priority Class A clear channels to commence PSRA operation at 6 a.m.
   local time and to continue such operation until the sunrise times
   specified in their basic instruments of authorization.

   (2) Class D stations situated outside 0.5 mV/m-50% skywave contours of
   co-channel U.S. Class A stations to commence PSRA operation at 6 a.m.
   local time and to continue such operation until sunrise times specified
   in their basic instruments of authorization.

   (3) Class D stations located within co-channel 0.5 mV/m-50% skywave
   contours of U.S. Class A stations, to commence PSRA operation either at
   6 a.m. local time, or at sunrise at the nearest Class A station located
   east of the Class D station (whichever is later), and to continue such
   operation until the sunrise times specified in their basic instruments
   of authorization.

   (4) Class B and Class D stations on regional channels to commence PSRA
   operation at 6 a.m. local time and to continue such operation until
   local sunrise times specified in their basic instruments of
   authorization.

   (c) Extended Daylight Saving Time Pre-Sunrise Authorizations:

   (1) Between the first Sunday in April and the end of the month of
   April, Class D stations will be permitted to conduct pre-sunrise
   operation beginning at 6 a.m. local time with a maximum power of 500
   watts (not to exceed the station's regular daytime or critical hours
   power), reduced as necessary to comply with the following requirements:

   (i) Full protection is to be provided as specified in applicable
   international agreements.

   (ii) Protection is to be provided to the 0.5 mV/m groundwave signals of
   co-channel U.S. Class A stations; protection to the 0.5 mV/m-50%
   skywave contours of these stations is not required.

   (iii) In determining the protection to be provided, the effect of each
   interfering signal will be evaluated separately. The presence of
   interference from other stations will not reduce or eliminate the
   required protection.

   (iv) Notwithstanding the requirements of paragraph (c)(1) (ii) and
   (iii) of this section, the stations will be permitted to operate with a
   minimum power of 10 watts unless a lower power is required by
   international agreement.

   (2) The Commission will issue appropriate authorizations to Class D
   stations not previously eligible to operate during this period. Class D
   stations authorized to operate during this presunrise period may
   continue to operate under their current authorization.

   (d) Postsunset service authorizations (PSSA) permit:

   (1) Class D stations located on Mexican, Bahamian, and Canadian
   priority Class A clear channels to commence PSSA operation at sunset
   times specified in their basic instruments of authorization and to
   continue for two hours after such specified times.

   (2) Class D stations situated outside 0.5 mV/m-50% skywave contours of
   co-channel U.S. Class A stations to commence PSSA operations at sunset
   times specified in their basic instruments of authorization and to
   continue for two hours after such specified times.

   (3) Class D stations located within co-channel 0.5 mV/m-50% skywave
   contours of U.S. Class A stations to commence PSSA operation at sunset
   times specified in their basic instruments of authorization and to
   continue such operation until two hours past such specified times, or
   until sunset at the nearest Class A station located west of the Class D
   station, whichever is earlier. Class D stations located west of the
   Class A station do not qualify for PSSA operation.

   (4) Class D stations on regional channels to commence PSSA operation at
   sunset times specified on their basic instruments of authorization and
   to continue such operation until two hours past such specified times.

   (e) Procedural Matters. (1) Applications for PSRA and PSSA operation
   are not required. Instead, the FCC will calculate the periods of such
   operation and the power to be used pursuant to the provisions of this
   section and the protection requirements contained in applicable
   international agreements. Licensees will be notified of permissible
   power and times of operation. Presunrise and Postsunset service
   authority permits operation on a secondary basis and does not confer
   license rights. No request for such authority need be filed. However,
   stations intending to operate PSRA or PSSA shall submit by letter,
   signed as specified in § 73.3513, the following information:

   (i) Licensee name, station call letters and station location,

   (ii) Indication as to whether PSRA operation, PSSA operation, or both,
   is intended by the station,

   (iii) A description of the method whereby any necessary power reduction
   will be achieved.

   (2) Upon submission of the required information, such operation may
   begin without further authority.

   (f) Technical criteria. Calculations to determine whether there is
   objectionable interference will be determined in accordance with the AM
   Broadcast Technical Standards, § § 73.182 through 73.190, and applicable
   international agreements. Calculations will be performed using daytime
   antenna systems, or critical hours antenna systems when specified on
   the license. In performing calculations to determine assigned power and
   times for commencement of PSRA and PSSA operation, the following
   standards and criteria will be used:

   (1) Class D stations operating in accordance with paragraphs (b)(1),
   (b)(2), (d)(1), and (d)(2) of this section are required to protect the
   nighttime 0.5 mV/m-50% skywave contours of co-channel Class A stations.
   Where a 0.5 mV/m-50% skywave signal from the Class A station is not
   produced, the 0.5 mV/m groundwave contour shall be protected.

   (2) Class D stations are required to fully protect foreign Class B and
   Class C stations when operating PSRA and PSSA; Class D stations
   operating PSSA are required to fully protect U.S. Class B stations. For
   purposes of determining protection, the nighttime RSS limit will be
   used in the determination of maximum permissible power.

   (3) Class D stations operating in accordance with paragraphs (d)(2) and
   (d)(3) of this section are required to restrict maximum 10% skywave
   radiation at any point on the daytime 0.1 mV/m groundwave contour of a
   co-channel Class A station to 25 µV/m. The location of the 0.1 mV/m
   contour of the Class A station will be determined by use of Figure M3,
   Estimated Ground Conductivity in the United States. When the 0.1 mV/m
   contour extends beyond the national boundary, the international
   boundary shall be considered the 0.1 mV/m contour.

   (4) Class B and Class D stations on regional channels operating PSRA
   and PSSA (Class D only) are required to provide full protection to
   co-channel foreign Class B and Class C stations.

   (5) Class D stations on regional channels operating PSSA beyond 6 p.m.
   local time are required to fully protect U.S. Class B stations.

   (6) The protection that Class D stations on regional channels are
   required to provide when operating PSSA until 6 p.m. local time is as
   follows.

   (i) For the first half-hour of PSSA operation, protection will be
   calculated at sunset plus 30 minutes at the site of the Class D
   station;

   (ii) For the second half-hour of PSSA operation, protection will be
   calculated at sunset plus one hour at the site of the Class D station;

   (iii) For the second hour of PSSA operation, protection will be
   calculated at sunset plus two hours at the site of the Class D station;

   (iv) Minimum powers during the period until 6 p.m. local time shall be
   permitted as follows:
     Calculated power    Adjusted minimum power
   From 1 to 45 watts    50 watts.
   Above 45 to 70 watts  75 watts.
   Above 70 to 100 watts 100 watts.

   (7) For protection purposes, the nighttime 25% RSS limit will be used
   in the determination of maximum permissible power.

   (g) Calculations made under paragraph (d) of this section may not take
   outstanding PSRA or PSSA operations into account, nor will the grant of
   a PSRA or PSSA confer any degree of interference protection on the
   holder thereof.

   (h) Operation under a PSRA or PSSA is not mandatory, and will not be
   included in determining compliance with the requirements of § 73.1740.
   To the extent actually undertaken, however, presunrise operation will
   be considered by the FCC in determining overall compliance with past
   programming representations and station policy concerning commercial
   matter.

   (i) The PSRA or PSSA is secondary to the basic instrument of
   authorization with which it is to be associated. The PSRA or PSSA may
   be suspended, modified, or withdrawn by the FCC without prior notice or
   right to hearing, if necessary to resolve interference conflicts, to
   implement agreements with foreign governments, or in other
   circumstances warranting such action. Moreover, the PSRA or PSSA does
   not extend beyond the term of the basic authorization.

   (j) The Commission will periodically recalculate maximum permissible
   power and times for commencing PSRA and PSSA for each Class D station
   operating in accordance with paragraph (c) of this section. The
   Commission will calculate the maximum power at which each individual
   station may conduct presunrise operations during extended daylight
   saving time and shall issue conforming authorizations. These original
   notifications and subsequent notifications should be associated with
   the station's authorization. Upon notification of new power and time of
   commencing operation, affected stations shall make necessary
   adjustments within 30 days.

   (k) A PSRA and PSSA does not require compliance with § § 73.45, 73.182
   and 73.1560 where the operation might otherwise be considered as
   technically substandard. Further, the requirements of paragraphs
   (a)(5), (b)(2), (c)(2), and (d)(2) of § 73.1215 concerning the scale
   ranges of transmission system indicating instruments are waived for
   PSRA and PSSA operation except for the radio frequency ammeters used in
   determining antenna input power.

   (1) A station having an antenna monitor incapable of functioning at the
   authorized PSRA and PSSA power when using a directional antenna shall
   take the monitor reading using an unmodulated carrier at the authorized
   daytime power immediately prior to commencing PSRA or PSSA operations.
   Special conditions as the FCC may deem appropriate may be included for
   PSRA or PSSA to insure operation of the transmitter and associated
   equipment in accordance with all phases of good engineering practice.

   [ 56 FR 64860 , Dec. 12, 1991;  57 FR 43290 , Sept. 18, 1992, as amended at
    58 FR 27950 , May 12, 1993]