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.

[[Page 29]]

    (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.

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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, Secs. 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 V/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,

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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 Secs. 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]