b.
Frequency stability over operating temperature range:
plus or
minus 1 PPM.
c.
Modulation deviation:
plus or minus 5 kHz.
d.
Spurious and harmonic emissions:
85 dB down.
e.
RF power output:
[_____] watts nominal.
f.
Output impedance:
50 ohms.
2.6
TRANSMISSION LINE
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NOTE: The type and parameters of the transmission
lines are dependent on the distances between
transmitter and antenna.
a. Solid foam polyethylene dielectric helixes rated
at 2000 watts will be used when distance between
base station and antenna is 18.3 m (60 feet) or less.
b. Solid foam polyethylene dielectric helixes rated
at 3000 watts will be used when distance between
base station and antenna is between 18.6 m and 39.6
m (61 and 130 feet).
c. Air-polyethylene dielectric helixes rated at
5000 watts for VHF will be used when distance
between base station and antenna is between 39.9 m
and 61.0 m (131 and 200 feet). For UHF, and
specific applications, consult manufacturer.
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Transmission line shall be corrosion-resistant polyethylene-jacket type
with inner and outer copper conductors, separated by [solid foam
polyethylene dielectric] [air polyethylene dielectric] helixes. The line
shall have a minimum bending radius of ten times the outside diameter and
an average power rating of [2000] [3000] [5000] watts. Adapter kits for
termination to antenna and base station shall be provided. Maximum
attenuation at the specified frequency shall not exceed 1.51 dB per 30.5 m
100 feet.
2.7
ANTENNA
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NOTE: The type of antenna indicated is applicable
to some of the transmission sites. Based on the
radiating space and coverage required, consult
manufacturers to determine parameters of the correct
antenna for the specific application.
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Antenna and antenna structure shall conform to EIA ANSI/TIA/EIA-222-F and
EIA ANSI/EIA/TIA-329-B. The antenna shall be [omnidirectional and
vertically polarized 2 MHz band width, 500 watt power rating, 50 ohms
nominal impedance, a voltage standing wave ratio of 1.5 to 1 or less, and a
minimum gain of 2.8 dB over a half-wave dipole] [_____]. The antenna shall
SECTION 16755A
Page 11
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