Product Introduction - SMC Networks LOOPANTNVIS3 Operator's Manual

Product Introduction

The Folding Loop Antenna has been designed and manufactured to meet the
requirements of NVIS HF mobile communications for both on-road and off-road
vehicles.
High conductivity tubing is used in the loop element to provide high
communication efficiency, and a custom-modified electronic tuner is used to
provide a 50-ohm nominal termination impedance at all operating frequencies.
The termination arrangement is hermetically sealed to IP66 specifications.
Following initialisation, where the tuner unit memorises each operating frequency
used by the HF transceiver, each subsequent tune operation is completed within
10 mS. This is achieved by the tuner having on-board memory to instantaneously
measure and determine the operating frequency of each operating channel, and
to switch in the required matching configuration for each stored channel. The
Folding Loop Antenna is inherently compatible with virtually any HF transceiver
over the operational frequency range and power rating with no separate channel
control required for the antenna.
The radiation pattern presented by the Folding Loop Antenna is shown above
in 3D, giving maximum radiation in an arc from the front of the vehicle, over the
vehicle (thus giving excellent NVIS performance), and to the rear of the vehicle.
The front and rear radiation paths also provide excellent results for ground-wave
communication between a fleet of vehicles travelling in line. This assumes the
loop is mounted with the element in the same plane as the line of the vehicle (i.e.
from front to rear) and with the Folding Loop Antenna in the Operational
Position.
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