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Linear Amp UK specializes in the design and production of high-quality linear amplifiers, offering models for HF, VHF, and UHF amateur and commercial applications. The company emphasizes nearly 30 years of experience in crafting each unit, ensuring robust performance and longevity. Their product line includes amplifiers engineered for a 100% duty cycle, promoting continuous and reliable operation across various modes. The amplifiers feature solid, dependable designs, ensuring quiet and effortless performance during transmission. Each unit is hand-built to stringent standards, reflecting a commitment to durability and operational stability. All products are CE approved, confirming compliance with European safety and environmental directives, and come with a standard two-year warranty, providing assurance to operators. Key specifications often include coverage for 1.8-30MHz (WARC bands), 50MHz, 70MHz, and 144MHz, utilizing tubes such as 811, 572, 811A, 572B, GS35, GS35B, 8877, 3CX1500, and _3CX1500A7_ in their designs.

What makes a good solid-state amp ? by Adam Farson, VA7OJ/AB4OJ, May 2002

ON6MU Low Power amplifier

High impedance amplifiers for shortened vertical antennas, Array matched and Optimized 15dB Preamplifier

The Pecker is a software application that emulates an existing hardware amplifier tuning aid operated in SSB mode as apposed to CW or AM. As such no carrier is used by G7EIX

Amplifier repair and conversion, specialize in converting HF amplifiers to operate as monoband amps on 50 MHz

A page dedicated to Yaesu FL-2100Z linear amplifier for amateur hf bands

Specialize in engineering, design and repair of all rf equipment. Dealer for two way radios, scanners, shortwave radios, wi-fi antennas, wifi amplifiers. Based in Fortuna, California.

The Ameritron ALS-600 600-Watt HF Power Amplifier review by AD5X

Pictures of a monoband linear amplifier for 40m band - 2 x QB5/1750 made by 9A6A

An easy to build with a cheap HEMT FET Transistor Low noise preamplifier with FHX35LG based on JH0WJF design

AL-811 and AL-811H specifications and information about this 600-800 Watt ham radio ower amplifiers

Mark Connelly, WA1ION article on Medium Frequency Amplifier Circuits in PDF format, include some RF amplifier schematics

Two coupled PAs with each 2 times 2C39 deliver around 400W RF.

This test circuit is easy to duplicate, and demonstrates the extreme voltages that appear in an amplifier when the load is improper for the amount of drive power applied.

100 W output RF amplifier for 10 meter band project by W4NFR

Design and manufacture application specific microwave and RF amplifiers, upconverters, downconverters and multifunction assemblies.

A complete restoration of a Heathkit SB-200 HF power amplifier

Understanding Solid State Linear Amplifiers

How to connect and key Power Amplifiers to Kenwood TS 590 or TS 990. How to home made custom Remote cable to key power amplifiers by JG1VGX

Homebrew Tubes/LDMOS amplifiers, Antenna, accessories, adventures in 9Q, DX, UN missions, Contests, and more.

This project is an interface box for the Yaesu FT-817 that includes a band output port, a computer serial interface, and a remote interface for the FL-7000 solid state power amplifiers.

Improper tank adjustment and excessive drive are equally harmful to component life, and either can create splatter

HobbyPCB.com provides quality products and boards for amateur radio including the popular HARDROCK 50 amplifier

Linear amplifier related mailing list

1500 watts of RF output on the 70cm band requires robust amplifier design, a challenge addressed by this project featuring the GS-23b / 4CX1600U Svetlana tube. The resource details the construction of a high-power UHF amplifier, providing insights into component selection and layout necessary for stable operation at these frequencies and power levels.

Constructing a high-power 70cm solid-state amplifier presents unique challenges, particularly when aiming for 500 watts output using modern LDMOS devices. This resource details the author's experience building a 70cm amplifier based on a _Freescale MRFE6VP5600H_ transistor, initially from an RFHAM kit. It meticulously outlines the necessary modifications to achieve advertised performance, including optimizing input and output matching, correcting bias circuitry, and ensuring proper output balun connections for stability. The author shares specific adjustments, such as trimming the prototyping board for better transistor fit, drilling additional mounting holes for improved heat sinking, and replacing original matching capacitors with a single _20pf MIN02 metal mica_ for superior output. A critical fix involved jumpering gate decoupling pads to balance the push-pull transistor halves, which increased output to 580W and improved IMD. The resource also highlights a crucial correction to the output balun connection, initially reversed in the _Dubus_ article schematic, which resolved intermittent stability issues. Test results are provided, showing input power, output power, and drain current at 50V, demonstrating the amplifier's performance after modifications. This practical account offers valuable insights for hams undertaking similar high-power UHF amplifier projects, especially those working with LDMOS devices and kit-based constructions.

A 50MHz kW Amplifier by Goran Grubishic, 9A6C

Collection of Kenwood TL-922 linear amplifier modifications

A simple free running oscillator oscillating at the receiver\'s IF (intermediate frequency) beats with the incoming signals in either CW or SSB and the resultant audio frequency goes to the AF amplifier.

Excellent article and guide to choose the best RF power amplifier that fit your needs by ON4SKY

A well documented PDF document containing picture sequence taked during the repair of an Icom IC-7700 HF transceiver power amplifier module

Optimizing weak signal reception on the HF bands, particularly in the presence of strong local QRM, often necessitates specialized receiving antenna systems. This resource details the _HI-Z Antennas_ product line, focusing on phased vertical arrays designed for superior noise rejection and directivity. It covers components such as the 4-Square and 8-Element array controllers, which allow for rapid switching of receive patterns, and dedicated low-noise preamplifiers to improve system sensitivity. The site also presents various bandpass filters, crucial for mitigating out-of-band interference and enhancing the dynamic range of the receiver. The HI-Z systems are engineered to provide significant front-to-back and side rejection, often yielding **20-30 dB** of attenuation to unwanted signals, which is critical for DXing and contesting. Users can achieve a notable reduction in local noise, allowing for the discernment of signals that would otherwise be buried. The array controllers facilitate quick pattern changes, enabling operators to null out interference or peak weak signals from distant stations, effectively extending the reach of their receive capabilities by improving the signal-to-noise ratio.

A collection of modifications and improvements to the Ameritron ALS-600 ham radio RF power amplifier

An amplifier made using an old HT-41 Hallicrafters Amplifier and adding the 160 meters band By W4NFR

eHam reviews for the Ameritron AL-811 linear amplifier

This video will provide a foundation for understanding how power amplifier circuits work. If you are new to High Frequency Power Amplifier Circuit Design, this is the place to start.

Home Brew a 4-1000A RF power amplifier project by W4NFR

Operating the _Icom IC-746_ HF/VHF transceiver often presents specific technical questions, and this resource compiles a comprehensive Frequently Asked Questions (FAQ) document in an ASCII text format. It details common inquiries and solutions related to the rig's functionality, accessories, and potential modifications. The content is structured into distinct sections addressing general information, power supplies, antennas, microphones, keyers, amplifiers, TNC integration, and optional IF filters. The FAQ provides practical guidance on topics such as configuring the internal automatic antenna tuning unit (ATU), selecting appropriate power supplies, and understanding microphone pin-outs. It also delves into advanced subjects like computer control via CI-V, wiring for PSK31 operation, and troubleshooting common issues like low S-meter readings on 2m FM or loose tuning shafts. Specific questions cover the installation of optional IF filters, comparing Inrad versus Icom filters, and optimizing filter combinations for various modes. Furthermore, the document outlines various hardware and firmware modifications, including those for increasing monitor volume, replacing LCD driver transistors, and implementing a "poor man's TCXO." It even touches upon untested modifications, such as replacing PIN diodes in the demodulator. The FAQ also lists manual errata and discrepancies, offering a robust knowledge base for IC-746 owners seeking to optimize their station or resolve operational challenges.

EB5AGV Workbench: Yaesu FL-2100B amplifier restoration

A 160W linear amplifier for 4 meters band based on GI0GDP

This article describes an alternative to water as the cooling liquid for amateur radio vacuum tube power amplifiers. This cooling system is designed for adequate vacuum tube cooling, reasonable cost, and very low maintenance. By K8CU

Article on evaluating HF Power amplifiers and review of popular PA by K0BG

Design Guidelines for JFET Audio Preamplifier Circuits By Mike Martell N1HFX

Replacing the Yaesu FT100D SRF7043 VHF/UHF RF MOSFET Power Amplifier

The Superphaser-2 is an antenna phasing unit based on the PSA-A Phase Shift Amplifier module

Manual of the BD-35 Dual Band VHF UHF RF power amplifier by Mirage Amp

A home made 50 MHz KW power amplifier project with picture and PCB schematic by W6PQL

A 600W 1.8 MHz to 54 MHz power linear amplifier made using rugged MRF300 transistors featuring output power between 580W and 750W depending on band, power supply: 48V, 18A typical, 20A max

Mods.dk collection of Ameritron ALS-600 power amplifier