§  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 § 73.1690, Modification of transmission systems, and
   specified therein.

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

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

   (5) Installation of TV stereophonic or subcarrier transmission
   equipment pursuant to § § 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 § 73.44
   for AM stations; § 73.317 for FM stations and § 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]