IF and associated interface requirements applicable to Satellite Communications SATCOM Earth Terminals ET operating over military X-band and Ka-band Super High Frequency SHF channels. Military unique requirements for ET that may operate over commercial C-band, Ku-band, and Ka-band are included. Equipment developers may exceed the requirements herein to satisfy specific program requirements, provided that interoperability is maintained. Thus, incorporating additional standard and nonstandard capabilities and interfaces is not precluded. Existing SHF SATCOM terminals need not conform to this MIL-STD unless they undergo a modernization program.

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MIL-STD-188-164B

5. DETAILED REQUIREMENTS

5.1 General. The paragraphs in this section apply to the specific terminals referenced in the standard.

5.2 C-band antennas.

5.2.1 Antenna sidelobe levels, uplink (transmit). The terminal antenna and RF performance shall be in accordance with the mandatory requirements of IESS-601 or the performance standards established in 47CFR Part 25, as appropriate for the anticipated class of terminal operation.

5.2.2 Antenna polarization, transmitting. The antennas shall be able to transmit horizontal linear and vertical linear polarizations simultaneously and right-hand circular and left- hand circular polarizations simultaneously. However, these terminals are not required to operate with both linear and circular polarizations at the same time. The ET linear feed shall be adjustable to match the satellite polarization angle to within 1-degree (clear sky).

5.2.3 Axial ratio, circular polarization, transmitting.

The axial ratio applies to all directions within the cone defined by the antenna pointing errors that corresponds to the appropriate pointing loss requirement (see IESS 601, transmit and receive axial ration section).

a. Circular polarized antennas with diameter larger than

2.5 meters. The voltage axial ratio of transmission in the direction of the satellite shall not exceed 1.09 (27.3 dB polarization discrimination).

b. Circular polarized antennas with diameter 2.5 meters or smaller. The voltage axial ratio of transmission in the direction of the satellite shall not exceed 1.3 (17.7 dB polarization discrimination).

c. Linear polarized antennas with diameter larger than 4.5 meters. The voltage axial ratio of transmission in the direction of the satellite shall exceed 31.6 (30.0 dB polarization discrimination).