Sec.  73.1590   Equipment performance measurements.

   (a) The licensee of each AM, FM, TV and Class A TV station, except licensees
   of Class D non-commercial educational FM stations authorized to operate with
   10 watts or less output power, must make equipment performance measurements
   for each main transmitter as follows:

   (1) Upon initial installation of a new or replacement main transmitter.

   (2) Upon modification of an existing transmitter made under the provisions
   of  Sec. 73.1690, Modification of transmission systems, and specified therein.

   (3) Installation of AM stereophonic transmission equipment pursuant to
    Sec. 73.128.

   (4) Installation of FM subcarrier or stereophonic transmission equipment
   pursuant to  Sec. 73.295,  Sec. 73.297,  Sec. 73.593 or  Sec. 73.597.

   (5) Installation of TV stereophonic or subcarrier transmission equipment
   pursuant to  Sec.  Sec. 73.669 and 73.1690.

   (6) Annually, for AM stations, with not more than 14 months between
   measurements.

   (7) When required by other provisions of the rules or the station license.

   (b) Measurements for spurious and harmonic emissions must be made to show
   compliance with the transmission system requirements of  Sec. 73.44 for AM
   stations;  Sec. 73.317 for FM stations and  Sec. 73.687 for TV stations. Measurements
   must be made under all conditions of modulation expected to be encountered
   by the station whether transmitting monophonic or stereophonic programs and
   providing subsidiary communications services.

   (c) TV visual equipment performance measurements must be made with the
   equipment adjusted for normal program operation at the transmitter antenna
   sampling port to yield the following information:

   (1) Field strength or voltage of the lower side-band for a modulating
   frequency of 1.25 MHz or greater, (including 3.58 MHz for color), and of the
   upper side-band for a modulating frequency of 4.75 MHz or greater.

   (2) Data showing that the waveform of the transmitted signal conforms to
   that specified by the standards for TV transmissions.

   (3) Photographs of a test pattern taken from a receiver or monitor connected
   to the transmitter output.

   (4) Data showing envelope delay characteristics of the radiated signal.

   (5) Data showing the attenuation of spurious and harmonic radiation, if,
   after type acceptance, any changes have been made in the transmitter or
   associated equipment (filters, multiplexer, etc.) which could cause changes
   in its radiation products.

   (d) The data required by paragraphs (b) and (c) of this section, together
   with a description of the equipment and procedure used in making the
   measurements, signed and dated by the qualified person(s) making the
   measurements, must be kept on file at the transmitter or remote control
   point for a period of 2 years, and on request must be made available during
   that time to duly authorized representatives of the FCC.

   [ 47 FR 8589 , Mar. 1, 1982, as amended at  51 FR 18450 , May 20, 1986;  65 FR 30004 , May 10, 2000]