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AS-1735/SRC
VTM-01-003C
Valcom Mfg Grp, Inc.
-10-
3.0 OPERATION
3.1
Functional Description
The AS-1735/SRC antenna consists of four dipole radiators fed in phase and positioned equally
spaced around a circular mast. This configuration provides an omnidirectional radiation pattern
in the azimuth plane over the frequency range of 225 MHz to 400 MHz which is capable of
power inputs up to 2 kW peak.
The dipole elements are supported by an aluminum frame which also forms the outer conductors
of the coaxial feed lines and transformers. Each dipole is fed through a balun and utilizes
isolation traps to limit the flow of current in the mast.
The impedance of the radiating elements is essentially high. Impedance matching is achieved by
pairing two elements in parallel and then parallelling those with the other two elements, which
are also in parallel to each other.
The radiation pattern of the antenna is essentially that of a vertically polarized dipole. When the
antenna is mounted on masts of 11 inches in diameter or smaller, the radiation pattern is
omnidirectional to within ±1.5 dB. When the antenna is mounted on larger diameter masts, the
pattern tends to show slight nulls but is still relatively omnidirectional.
The design of the antenna has been driven to provide a lightweight, rugged, reliable and
weatherproof antenna. This has been achieved through minimal assembly parts and in such a
way that installation can be done in a variety of ways without noticeable differences in operation
performance.
3.2
Operating Procedures
The AS-1735/SRC exhibits complete broadband operation over the frequency range of 225 MHz
to 400 MHz in which the antenna requires no special procedures to operate. The antenna is
ready to use upon completion of installation.