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Use 4CX10000D / 8171, RF output power of 11 KW in key-down carrier on all bands. Power was measured with a Bird 4712 wattmeter and a 25 KW slug

A 144 MHz kilowatt amplifier project details the construction and performance of a high-power VHF linear using the GU74b tetrode. This Russian tube, equivalent to the Svetlana 4CX800, is noted for its conservative datasheet ratings, performing closer to 800-1000W anode dissipation in practical applications. The design prioritizes compactness and achieves 1.2 kW output with only 20W of drive power, demonstrating a 70% efficiency at 2.5 kV plate voltage. The amplifier has been successfully deployed in demanding _EME_ (Earth-Moon-Earth) operations since June 1994. Challenges encountered during development included achieving stability with a grid-1 input configuration. The author, _CT1DMK_, opted not to publish the full design due to its complexity, suggesting it might be difficult for less experienced builders to replicate successfully. However, he invites direct contact for those with specific interest in the design. Future plans include a "144MHz GS35b compact amplifier" project, promising another kilowatt-plus design. This resource offers insights into high-power VHF amplifier construction and the practical application of specific power tubes.

This article loaded with nice pictures and schematics, describes a 160-10 meter linear amplifier that uses a pair of 3-500Z triode power tubes. It was designed and constructed by William Moneysmith, W4NFR. The amplifier features fast warm up and 1500-Watt RF output with 100-Watts of drive.

This document details the design and construction of the PA70H, a 50-watt RF amplifier for the 70MHz (4-meter) amateur radio band. Built around the Mitsubishi RD70HVF1 MOSFET transistor, the amplifier delivers 45-55W output with 3-5W input power while operating on 13.8V DC at approximately 7-8A. The PCB design incorporates multiple protection circuits including overcurrent, SWR, and temperature control. The amplifier features various control modes including GND PTT, +13.8V PTT, and RF VOX. Two versions are available: PA70HLI (requiring 100mW input with additional driver) and PA70H (for 3-5W input). The comprehensive documentation includes circuit diagrams, assembly instructions, and performance data showing successful operation from both 100mW and 3.5W input sources.

Article about assembling of a Dick Smith Electronics (DSE) 100 Watt VHF Linear Amplifier kit.

Bi-Directional 2.4 GHz One Watt Amplifier With Receive Pre-Amplifier. This will show you how to add a bi-directional, 2.4 GHz amplifier to your Proxim Symphony for under $100

This page details my building of a 100 Watt Power Amplifier for the 432 MHz Band based on two Motorola MRF646 transistors taking inspiration by Carlo Gnaccarini VK3PY, formerly VK3BRZ

The Elecraft KX2 is presented as a highly portable QRP transceiver, covering 80-10 meters with SSB, CW, and data modes. Key specifications include its remarkably light weight of only **13 ounces** (0.3 kg), an optional internal 2.6 Ah Li-ion battery, and an internal wide-range automatic antenna tuner (ATU). This _software-defined radio_ (SDR) architecture incorporates advanced DSP features such as dual watch, noise reduction, noise blanking, and autonotch, alongside built-in PSK31/RTTY data mode operation without requiring an external PC. Designed for maximum portability, the KX2 measures 5.8 x 2.8 x 1.5 inches and delivers up to **10 watts** of output power. Its low current drain of 135 mA allows for up to 8 hours of typical operation on a single battery charge, making it suitable for field deployment. The transceiver also features a built-in microphone for HT-style use and is compatible with the KXPA100 amplifier, offering versatility for various operating scenarios from desktop to mobile or handheld.

The Icom IC-PW1 is a 1000 watt linear amplifier with built-in power supply

Modification to an old cellular phone base station modules, with a fairly reduced output power (10 watts or so), the stock power amplifier modules will cover the 2.3 GHz and 2.4 GHz amateur radio bands.

Demonstrates the conversion of an _Elecraft K2_ QRP HF transceiver to serve as a 2-meter Intermediate Frequency (IF) rig for microwave transverters, addressing the obsolescence of older _Yaesu FT-290R_ units. The project integrates a _DEMI 144-28DC_ transverter board, configured for a 28 MHz IF, and details the necessary modifications to the K2, including the installation of the K160M module for a separate receive-only antenna input and the KSB2 SSB module for voice operation. The modified K2 provides a stable 1-watt output for the 2m IF, utilizing the QRP antenna jack for transmit and the K160M input for receive, with a custom PTT control circuit. The article outlines the physical integration and electrical interfacing, including the design of an internal attenuator for the 28 MHz IF output and a control circuit for the 144 MHz interface. It also covers the construction of a medium power amplifier using an _MGA-31389 MMIC_ to boost the 2m output to 100 mW, matching the original FT-290R performance. Performance measurements for the amplifier, including output power versus input power and gain versus frequency, are presented. The project culminates in a fully integrated solution, with schematics and photos illustrating the internal wiring and external connectors. The modified K2, dubbed the "K290R," was successfully deployed in the 2017 _ARRL 10 GHz and Up Contest_ with a _Kuhne 10 GHz_ transverter, demonstrating reliable operation for CW and SSB modes.

The Olivia digital mode, a **Multi-Frequency Shift Keying (MFSK)** radioteletype protocol, is specifically engineered for robust communication under difficult propagation conditions on shortwave radio bands from 3 MHz to 30 MHz. Developed by Pawel Jalocha in 2003, Olivia signals can be decoded even when the noise amplitude exceeds the digital signal by over ten times, making it highly effective for transmitting ASCII characters across noisy channels with significant fading and propagation phasing. Early on-the-air tests by Fred OH/DK4ZC and Les VK2DSG on the Europe-Australia 20-meter path demonstrated intercontinental contacts with as little as one-watt RF power under favorable conditions. Common Olivia modes are designated as X/Y, where X represents the number of tones and Y is the bandwidth in Hertz, with examples including 8/250, 16/500, and 32/1000. The resource clarifies that Olivia, unlike some other digital modes, produces a constant envelope, allowing RF power amplifiers to achieve greater conversion efficiencies and making it less prone to non-linearity. Operators are advised that **Automatic Level Control (ALC)** can be set higher than no meter movement for MFSK modulation, as long as it's not driven past its high limit, contrary to common misinformation about other digital modes. The Olivia community encourages voluntary channelization on suggested calling frequencies, such as 14.0725 MHz for 8/250, to facilitate initial contacts, especially for signals below the noise floor. The Olivia Digital DXers Club provides links to Groups.io, Facebook, and Discord for community engagement and offers details on QSO parties.

The Yaesu FTDX10 MF/HF and 6-meter transceiver, a 100-watt rig, is designed to bring high-performance receiver architecture to the intermediate-price class. It offers continuous receive coverage from 30 kHz to 75 MHz and transmit capabilities across all amateur bands from 160 through 6 meters, including five preset CW and SSB channels on 60 meters. The transceiver supports AM, FM, SSB, CW, and digital modes, with integrated decoders for CW, RTTY, and PSK31, making it a versatile station for various operating preferences. Physically, the FTDX10 measures 3½ × 10½ × 10½ inches and weighs 13 pounds, requiring a 20–25 A DC power supply for full 100 W output. Its front panel features a 5-inch TFT color touchscreen and a large VFO knob, complemented by an SD memory card slot for recording audio and saving settings. Rear panel connectivity includes a single SO-239 antenna port, multiple USB ports for CAT control and peripherals, and DIN jacks for external digital mode hardware and linear amplifiers, though it lacks a dedicated low-noise receive antenna provision. ARRL Lab tests confirm excellent receiver performance, with blocking dynamic range exceeding 137 dB at 2 kHz spacing and robust IMD dynamic range figures. The hybrid receiver design incorporates selectable roofing filters at 500 Hz, 3 kHz, and 12 kHz, along with two preamplifiers and various attenuation levels, allowing operators to tailor reception characteristics to challenging band conditions. Transmitter performance is also rated very good, with low transmit phase noise.