Technical Articles

RF Ferrite Isolator Basics

RF Ferrite Isolator Basics

An isolator is a type of non-reciprocal passive network that allows designers the freedom to construct networks where the transmission coefficient in one direction does not necessarily have the same loss as in the reverse direction. In an isolator, ideally, RF energy can be made to flow through it in only one direction.

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Choosing TX and RX Filters

Choosing TX and RX Filters

TX and RX filters select a specific portion of the RF or microwave signal based on the desired frequency, and reject the rest of the signal being transmitted or received. The range of frequencies that are passed by a filter are called the pass-band, the ranges of frequencies that need to be rejected are called stop-bands. Unless otherwise specified, filters reflect energy in the stopbands, rather than absorb it.

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Crossband Couplers

Crossband Couplers

A crossband coupler is a three-port network that allows transmitters and receivers of different frequency bands to share a single feedline to an antenna. It does this by using low-pass, high-pass, or band-pass filters to isolate the desired signals from each other, with very low loss in both paths to the antenna.

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Types of Antenna Coatings

Types of Antenna Coatings

Any time there are RF or any electrical equipment out in the field, it’s going to be subject to a wide range of environmental factors. Extremes of temperature, wind-blown debris, and moisture from rain or snow even dew can all interfere with signals you’re trying to transmit or receive.

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Types of Coaxial Terminations (Dry versus Oil-Filled)

Types of Coaxial Terminations (Dry versus Oil-Filled)

A coaxial termination is a device that can be placed on one end of a coaxial transmission line to absorb the transmitted signals without impacting other system components. A termination presents a “matched load” to the system impedance (usually 50 or 75 ohms), so that a terminated transmission line will behave like an infinitely long line where the signal never has a chance to reflect back to the signal source.

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A Brief Guide to Telewave’s Cavity Filters

A Brief Guide to Telewave’s Cavity Filters

Cavity filters are one of many types of Radio Frequency (RF) filters, and are one of the fundamental building blocks of modern communications systems. This paper describes the basics of cavity filters. For additional information about specific Telewave cavity filters and solutions that employ the filters, please visit our web site at www.telewave.com.

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Tips on Navigating Cavity Filter Types, Performance, and Features

Tips on Navigating Cavity Filter Types, Performance, and Features

Cavity filters are a type of resonant filter used for either passing desired RF signals within a specified frequency range or rejecting RF signals within a range of frequencies. The resonant cavity within these filters can be constructed from durable materials, such as highly conductive and dimensionally stable metals, to reliably perform for years in harsh environments.

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Benefits of Intermodulation Suppression Panels for Congested Sites

Benefits of Intermodulation Suppression Panels for Congested Sites

It is common for multiple radio and wireless service providers to share communications sites and cell towers, and this proximity often results in spectrum congestion. Radio frequency interference can originate from a wide number of sources, from natural phenomena such as lightning and sun spots to high power broadcast systems like AM/FM radio and TV transmitters, 2-way radio, paging, cell phones, and emergency and public safety communications systems, power lines, transformers, medical equipment, as well as any device that produces RF energy.

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How to Select Receiver Distribution Panels – Weighing the Features and Performance Factors

How to Select Receiver Distribution Panels – Weighing the Features and Performance Factors

An ideal telecommunications tower site would have every band in critical industrial, commercial, and public safety spectrum fitted with a dedicated antenna and receive unit for optimum sensitivity. However, the large size of 30 MHz to 960 MHz antennas and radio equipment, and the congestion of many tower sites, often requires the receive antennas to pull double-, or multi-, duty.

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