View all text of Subpart G [§ 74.701 - § 74.799]
§ 74.735 - Power limitations.
(b) The maximum ERP of a low power TV or TV translator station (average power) shall not exceed:
(1) 3 kW for VHF channels 2–13; and
(2) 15 kW for UHF channels 14–36.
(c) The limits in paragraph (b) of this section apply separately to the effective radiated powers that may be obtained by the use of horizontally or vertically polarized transmitting antennas. For either omnidirectional or directional antennas, where the ERP values of the vertically and horizontally polarized components are not of equal strength, the ERP limits shall apply to the polarization with the larger ERP. Applications proposing the use of directional antenna systems must be accompanied by the following:
(1) Complete description of the proposed antenna system, including the manufacturer and model number of the proposed directional antenna. It is not acceptable to label the antenna with only a generic term such as “Yagi” or “Dipole”. A specific model number must be provided. In the case of individually designed antennas with no model number, or in the case of a composite antenna composed of two or more individual antennas, the antenna should be described as a “custom” or “composite” antenna, as appropriate. A full description of the design of the antenna should also be submitted.
(2) Relative field horizontal plane pattern (horizontal polarization only) of the proposed directional antenna. A value of 1.0 should be used for the maximum radiation. The plot of the pattern should be oriented so that 0° corresponds to the maximum radiation of the directional antenna or, alternatively in the case of a symmetrical pattern, to the line of symmetry. The 0° on the plot should be referenced to the actual azimuth with respect to true North.
(3) A tabulation of the relative field pattern required in paragraph (c)(2), of this section. The tabulation should use the same zero degree reference as the plotted pattern, and be tabulated at least every 10°. In addition, tabulated values of all maximas and minimas, with their corresponding azimuths, should be submitted.
(4) All horizontal plane patterns must be plotted to the largest scale possible on unglazed letter-size polar coordinate paper (main engraving approximately 18 cm × 25 cm (7 inches × 10 inches)) using only scale divisions and subdivisions of 1, 2, 2.5 or 5 times 10-nth. Values of field strength on any pattern less than 10% of the maximum field strength plotted on that pattern must be shown on an enlarged scale.
(5) The horizontal plane patterns that are required are the patterns for the complete directional antenna system. In the case of a composite antenna composed of two or more individual antennas, this means that the patterns for the composite antenna composed of two or more individual antennas, not the patterns for each of the individual antennas, must be submitted.