#### § 78.105 Antenna systems.

(a) For fixed stations operating in the 12.7-13.2 GHz and 17.7-19.7 GHz bands, the following standards apply:

(1) Fixed CARS stations shall use directional antennas that meet the performance standards indicated in the following table.

(i) Stations must employ an antenna that meets the performance standards for Category B. In areas subject to frequency congestion, where proposed facilities would be precluded by continued use of a Category B antenna, a Category A antenna must be employed. The Commission may require the use of a high performance antenna where interference problems can be resolved by the use of such antennas.

(ii) Upon adequate showing of need to serve a larger sector, or more than a single sector, greater beamwidth or multiple antennas may be authorized. Applicants shall request and authorization for stations in this service will specify the polarization of each transmitted signal.

(iii) Licensees shall comply with the antenna standards table shown in this paragraph in the following manner:

(A) With either the maximum beamwidth to 3 dB points requirement or with the minimum antenna gain requirement; and

(B) With the minimum radiation suppression to angle requirement.

Antenna Standards

| Frequency (MHz) | Category | Maximum beamwidith to 3 dB points1 (included angle in degrees) | Minimum antenna gain (dbi) | Minimum radiation suppression to angle in degrees from centerline of main beam in decibels | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 5° to 10° | 10° to 15° | 15° to 20° | 20° to 30° | 30° to 100° | 100° to 140° | 140° to 180° |
| 12,700 to 13,250 | A B | 1.0 2.0 | n/a n/a | 23 20 | 28 25 | 35 28 | 39 30 | 41 32 | 42 37 | 50 47 |
| 17,700 to 19,700 | A B | 2.2 2.2 | 38 38 | 25 20 | 29 24 | 33 28 | 36 32 | 42 35 | 55 36 | 55 36 |
| | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 If a licensee chooses to show compliance using maximum beamwidth to 3 dB points, the beamwidth limit shall apply in both the azimuth and the elevation planes. | | | | | | | | | | |

(2) New periscope antenna systems will be authorized upon a certification that the radiation, in a horizontal plane, from an illuminating antenna and reflector combination meets or exceeds the antenna standards of this section. This provision similarly applies to passive repeaters employed to redirect or repeat the signal from a station's directional antenna system.

(3) The choice of receiving antennas is left to the discretion of the licensee. However, licensees will not be protected from interference which results from the use of antennas with poorer performance than defined in [paragraph (a)](/on/2024-09-20/title-47/section-78.105#p-78.105(a)) of this section.

(4) Pickup stations are not subject to the performance standards herein stated. The provisions of this paragraph are effective for all new applications accepted for filing after October 1, 1981.

(b) Any fixed station licensed pursuant to an application accepted for filing prior to October 1, 1981, may continue to use its existing antenna system, subject to periodic renewal until April 1, 1992, After April 1, 1992, all licensees are to use antenna systems in conformance with the standards of this section. TV auxiliary broadcast stations are considered to be located in an area subject to frequency congestion and must employ a Category A antenna when:

(1) A showing by an applicant of a new CAR service or TV auxiliary broadcast, which shares the 12.7-13.20 GHz band with CARS, indicates that use of a category B antenna limits a proposed project because of interference, and

(2) That use of a category A antenna will remedy the interference thus allowing the project to be realized.

(c) As an exception to the provisions of this section, the FCC may approve requests for use of periscope antenna systems where a persuasive showing is made that no frequency conflicts exist in the area of proposed use. Such approvals shall be conditioned to require conversion to a standard antenna as required in [paragraph (a)](/on/2024-09-20/title-47/section-78.105#p-78.105(a)) of this section when an applicant of a new TV auxiliary broadcast or Cable Television Relay station indicates that the use of the existing antenna system will cause interference and the use of a category A or B antenna will remedy the interference.

(d) As a further exception to the provision of [paragraph (a)](/on/2024-09-20/title-47/section-78.105#p-78.105(a)) of this section the Commission may approve antenna systems not conforming to the technical standards where a persuasive showing is made that:

(1) Indicates in detail why an antenna system complying with the requirements of [paragraph (a)](/on/2024-09-20/title-47/section-78.105#p-78.105(a)) of this section cannot be installed, and

(2) Includes a statement indicating that frequency coordination as required in [§ 78.18a](/on/2024-09-20/title-47/section-78.18a) was accomplished.

[[45 FR 78694](https://www.federalregister.gov/citation/45-FR-78694), Nov. 26, 1980, as amended at [49 FR 37779](https://www.federalregister.gov/citation/49-FR-37779), Sept. 26, 1984; [50 FR 7343](https://www.federalregister.gov/citation/50-FR-7343), Feb. 22, 1985; [51 FR 19841](https://www.federalregister.gov/citation/51-FR-19841), June 3, 1986; [56 FR 50664](https://www.federalregister.gov/citation/56-FR-50664), Oct. 8, 1991; [62 FR 4923](https://www.federalregister.gov/citation/62-FR-4923), Feb. 3, 1997; [68 FR 12776](https://www.federalregister.gov/citation/68-FR-12776), Mar. 17, 2003]