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Portable Wire Antennas: The Must-Read Guide
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Portable Wire Antennas: The Must-Read Guide

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:NT$ 1896 元
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商品簡介

商品簡介

This is not a book on antenna theory. It does provide clear easily understood explanations on the principles of antenna operation, transmission line considerations, impedance matching, baluns, tuners, and the pros and cons of different types and configurations of wire antennas.


This book is written with the intention of enabling a new comer to amateur radio to understand the concepts and practical considerations of this subject without getting lost in mathematics and complex theory.


Portable, reliable HF communication is required for emergency management, expedition communications and recreational uses. This book is about selecting and constructing portable HF wire antennas that will provide maximum performance with low power, light weight and low bulk. All the information required to assemble antennas and antenna kits that can be deployed in multiple configurations is provided.


Special attention is given to wire antennas deployed at low heights above ground, a situation confronted by operators on the move. Special attention is also given to NVIS (Near Vertical Incident Skywave) communications, which is also optimum with low antenna elevation. NVIS propagation enables communications in the 50-500 mile range regardless of terrain and independent of repeaters.


With one to three low suspension points (8-20 ft.), one can deploy wire antennas that cover the 160-30 meter bands (those capable of NVIS propagation) with performance optimized for NVIS communication.


With a single high suspension point that can be improvised from one or two tall trees, buildings or cliff faces and one of the antenna launch systems described here, one can deploy multiple antenna options that can be configured from the modular antenna kit. These include inverted V resonant or random wire dipoles, long wire antennas, sloper dipoles and inverted L antennas for efficient all-band regional use.


It also covers long wire, two suspension point rhombics, terminated V beam and inverted half rhombic beam antennas optimized for 20-10 meters while being broad band (no tuner required), low noise and gain equal to or greater than a high dipole.


With two medium to high suspension points (15-80 ft. depending on the band), one can install Extended Double Zep or half square wire antennas that produce low angle radiation that is optimum for DX operation and yield 3 dBd of gain over a dipole.

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定價:100 1896
無庫存,下單後進貨
(到貨天數約30-45天)

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