Sec.  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  Sec. 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,  Sec.  Sec. 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  Sec. 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  Sec.  Sec. 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  Sec. 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]