[Code of Federal Regulations]
[Title 47, Volume 2]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR73.62]

[Page 26-27]
 
                       TITLE 47--TELECOMMUNICATION
 
        CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION (CONTINUED)
 
PART 73_RADIO BROADCAST SERVICES--Table of Contents
 
                     Subpart A_AM Broadcast Stations
 
Sec.  73.62  Directional antenna system operation and tolerances.

    (a) Each AM station operating a directional antenna must maintain 
the relative amplitudes of the antenna currents, as indicated by the 
antenna monitor, within 5% of the values specified on the instrument of 
authorization. Directional antenna relative phases must be maintained 
within 3 degrees of the values specified on the instrument of 
authorization.
    (b) In the event of a failure of system components, improper pattern 
switching or any other event that results in operation substantially at 
variance from the radiation pattern specified in the instrument of 
authorization for the pertinent time of day, operation must be 
terminated within three minutes unless power can be reduced sufficiently 
to eliminate any excessive radiation. See Sec.  73.1350(e).
    (1) Any variation of operating parameters by more than 15 percent sample current ratio or 10 degrees in phase, any monitor point that exceeds 125 
percent of the licensed limit, or any operation at variance that results 
in complaints of interference shall be considered operation 
substantially at variance from the license and will require immediate 
corrective action.
    (2) [Reserved]
    (c) In the event of minor variations of directional antenna 
operating parameters from the tolerances specified in paragraph (a) of 
this section, the following procedures will apply:
    (1) The licensee shall measure and log every monitoring point at 
least once for each mode of directional operation. Subsequent variations 
in operating parameters will require the remeasuring and logging of 
every monitoring point to assure that the authorized monitoring point 
limits are not being exceeded. The licensee will be permitted 24 hours 
to accomplish these actions; provided that, the date and time of the 
failure to maintain proper operating parameters have been recorded in 
the station log.
    (2) Provided each monitoring point is within its specified limit, 
operation may continue for a period up to 30 days before a request for 
Special Temporary Authority (STA) must be filed, pursuant to paragraph 
(c)(4) of this section, to operate with parameters at variance from the 
provisions of paragraph (a) of this section.

[[Page 27]]

    (3) If any monitoring point exceeds its specified limit, the 
licensee must either terminate operation within three hours or reduce 
power in accordance with the applicable provisions of Sec.  73.1350(d), 
in order to eliminate any possibility of interference or excessive 
radiation in any direction.
    (4) If operation pursuant to paragraph (c)(3) of this section is 
necessary, or before the 30-day period specified in paragraph (c)(2) of 
this Sec.  expires, the licensee must request a Special Temporary 
Authority (STA) in accordance with section 73.1635 to continue operation 
with parameters at variance and/or with reduced power along with a 
statement certifying that all monitoring points will be continuously 
maintained within their specified limits.
    (d) In any other situation in which it might reasonably be 
anticipated that the operating parameters might vary out of tolerance 
(such as planned array repairs or adjustment and proofing procedures), 
the licensee shall, before such activity is undertaken, obtain a Special 
Temporary Authority (STA) in accordance with Sec.  73.1635 in order to 
operate with parameters at variance and/or with reduced power as 
required to maintain all monitoring points within their specified 
limits.

[72 FR 44422, Aug. 8, 2007]