attempted unless there is ample signal strength to
enable one antenna to receive sufficient signal from
multiple sources to drive multiple head end inputs.
Reliability may suffer to some degree if one antenna
is used for more than one channel.
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Antenna shall be cut-to-channel or broadband model designed for heavy duty
commercial use, as shown.
2.1.1
Off-Air Television Antenna
2.1.1.1
Mechanical Specifications
Crossarms shall be high-strength aluminum alloy, seamless, with ends
sealed. Elements shall be high-strength aluminum alloy tubing, 10 mm 3/8
inch diameter, 635.0 micrometers 0.025 inch wall thickness. Antenna shall
be rated for an operational/survival wind velocity of 160.9 km/h 100 mph
with no ice. Antenna shall be completely weatherproofed. Aluminum shall
have an electrically conductive anti-corrosion (anodized) finish. Metals
for installation and mounting shall be high-strength non-corrosive type.
shall be a built-in, 75 ohm anodized brass, type F-61 connector.
2.1.1.2
Electrical Specifications
Antenna used for television off-air reception shall be yagi or log-periodic
type. Antenna shall as a minimum conform to the following specifications:
Gain Front-to-Back:
8 dBi
Ratio:
18
Output Impedance:
75 plus or minus 2 ohms unbalanced
Maximum VSWR:
1.5:1
Frequency Range:
[VHF] [, FM] [, UHF] [_____]
2.1.2
Off-Air FM Antenna
Antenna used for FM broadcast reception shall be [incorporated in the
broadband log-periodic] [a separate omni-directional] [a separate
directional] antenna. Antenna shall be designed for commercial application
and shall be completely weather and corrosion resistant. Electrical
characteristics shall be as specified for television off-air antenna with
the exception of gain, which shall be 2 dBi minimum for omni-directional or
7 dBi minimum for separate directional and broadband antennas.
2.1.3
Antenna Support Tower
Antenna support tower shall be designed to EIA ANSI/TIA/EIA-222-F
specifications and shall adhere to FAA AC 70/7460-1 and 47 CFR 17
requirements. Appropriate off-set antenna-tower mounts and downlead cable
supports shall be provided.
2.1.4
Transmission line connecting antenna and head end equipment shall be
SECTION 16785A
Page 13
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