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915 Wire Dipole - Barrett P/N BC91500
Single frequency wire dipole antennas, spot-tuned to the required operating
frequency(s), are the most efficient antennas for use in HF base stations. They are
simple to install and have a relatively narrow bandwidth.
Dipole antennas should be mounted at least 1/2 wavelength from the ground.
Dipoles may be mounted either between two towers or in an inverted "V"
configuration (requires only one mast). As a guide, when installing the masts, the
length between insulators of a half wave wire dipole is 142/(frequency of dipole in
MHz) metres. To this an allowance should be made for extra insulators and
halyards.
i.e. a 3.7 MHz dipole - length between the insulators = 142/3.7 =38.38 metres.
Wire dipoles supplied by Barrett are pre-cut to a specified frequency but have
adjustable ends. These adjustable ends allow fine tuning for optimum VSWR during
installation. To fine tune a dipole install the antenna in its final position and check
the antenna VSWR. Should the VSWR be greater than 5:1 the antenna will require
adjustment.
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