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A DIY guide to build your own compact multiband HF antenna based on the G3TXQ version using a 1:4 balun. This article includes the full part list and instructions to assembly, including the center plate.

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.

A comeplete home made 600W LDMOS RF power amplifier. Settings can be made on a 7-inch touch screen, and on this screen you can see a lot of useful information during operation, such as output power, temperature, SWR, and so on. The power amplifier includes 2 MRF300 LDMOS FETs and several built-in sensors. The amplifier also contains several types of protection functions like too high current, too high swr, too high temperature, etc.

Detailed pictures and description of antenna tower setup

Amateur Radio operation and weak signal detection pages by AF9Y

Decoding NOAA APT weather satellite images is achieved with a homebrew receiver and a Turnstile Cross Dipole antenna, feeding data to a Pentium-3 500MHz PC running Windows XP and the WXTOIMG program. This setup, operated by VU2IIA in Mumbai, India, focuses on capturing and processing signals from NOAA satellites to generate visual weather data. The blog documents the technical aspects of constructing the receiving station, including antenna design and receiver integration. It provides insights into the practical challenges and successes of amateur satellite reception, specifically for Automatic Picture Transmission (APT) signals. Operational details cover the software configuration and image processing workflow necessary to transform raw satellite data into usable weather imagery. The content serves as a practical guide for radio amateurs interested in satellite meteorology.

Earn your Technician or General Amateur Radio License in a one day course.

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With this tool it is possible to create QSO maps overlay on Google maps there each QSO get a line from the home location to each DX location. An EDI logbook file is used as input. The creation will only use complete locator in the 6 characters format.

Understanding Baluns. This article explores some simple antenna system configurations and the effect of key system components, connections and dimensions on feed line common mode current.

A Tropical Band Antenna with good Receiving characteristics

About ham radio hobby with hundreds of related links

Basic information compiled and copied from NOAA SEC explaining and showing current solar weather conditions affecting amateur radio.

Protecting the ham radio stations, using a good ground system

The International Amateur Radio Union

A cooperative venture between MSUARC and Calloway County Fire and Rescue

This article contains notes on installation of a Roger Beep for an Icom IC7000 transceiver for use with a Heilsound Traveller headset.

Speakers for Amateur Radio, 2-Way Radio, Shortwave and Scanner listening

West mountain radio, Useful electronic hobbyist products, RigBlaster and RIG Runners products, Waukesha, WI.

The Receiver Test Data resource is a detailed review database focusing on the performance metrics of various radio receivers. The methodology involves rigorous lab measurements, often adhering to standards such as the ARRL RMDR (Reciprocal Mixing Dynamic Range) and BDR (Blocking Dynamic Range). Specific test equipment and protocols are utilized to assess parameters like noise floor (dBm), AGC threshold (uV), and LO noise (dBc/Hz). For example, the _Icom IC-7300_ is evaluated with a noise floor of **-133 dBm** and an LO noise of **-141 dBc/Hz**, providing insights into its performance under different operational conditions. The resource includes a wide range of models, from the _Elecraft K3S_ to the _Yaesu FTdx-101D_, each tested for dynamic range, sensitivity, and selectivity. The data is sorted by key metrics such as third-order dynamic range and phase noise limitations, with RMDR values calculated by subtracting 27 dB from LO noise figures. This structured approach allows users to compare different receivers' capabilities, focusing on technical specifications and performance outcomes in various scenarios. DXZone Focus: Review Database | Lab Measurements | -133 dBm | ARRL RMDR

The Double 5/8 is a natural extension of the Single 5/8 and uses a 5/8λ element for both the top and bottom radiators.

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Cloudlog is a web-based amateur radio logging application built with PHP and MySQL, supporting station logging activities from HF to microwave. It integrates with companion tools for CAT control and automation, offering a flexible solution for managing QSO data. The application provides a self-hosted platform for amateur radio operators to maintain their logbooks, facilitating interaction with various ham radio operations. Its open-source nature allows for community contributions and customization, enhancing its utility for diverse operating preferences. Originally started by Peter, **2E0SQL**, Cloudlog was designed to enable simple interaction with the Ham Radio Deluxe logbook using MySQL.

The Yaesu FL2100Z is a HF linear amplifier rated for 1200W PEP input, and using two 572B triode tubes. This article explores the recommended operating conditions, and alternatives.

Article on tubes and their usage in power amplifiers design. Explain failures of tube in RF power amplifiers, a common problem in the SB-220 SB-221, TL-922 and other amplifiers.

The Western Washington DX Club is an organization of Amateur Radio (HAM) operators who have a special interest in DX or distance communications

Sams continues the tradition with the publication of new manuals every month, covering the latest in Televisions, including HDTV, Projections TVs, and coming soon, LCD monitors.

How to receive images from orbiting noaa weather satellites using simple receiving equipment and a computer by G4ILO

Presents the _K7AR DX NorthWest Web Cluster_, an online service for amateur radio operators to access real-time DX spots. The resource functions as a web-based interface, enabling users to monitor current band activity, identify rare DX stations, and track propagation conditions across various amateur bands. It aggregates spotting data, making it accessible without requiring a dedicated telnet client, thus simplifying access for many hams. The cluster integrates with the broader DX spotting network, offering a continuous stream of reported contacts. While specific performance metrics are not detailed, such web clusters typically update spots within **seconds** of submission, providing timely information crucial for DXing and contesting. Its utility lies in offering a quick, browser-based overview of the airwaves, comparable to traditional telnet clusters but with enhanced accessibility.

Metro Vector Network Analyzer is a custom antenna analyzer designed and produced by IZ7LDG.

Columbus Police Dispatch - Citywide Live Audio Feed

This project produces a sturdy tripod for small vertical antenna support using readily available electrical metal tubing (EMT) or conduit

Dimensions and EZNEC plots for a 2 Element 30 meter Yagi antenna with 28 Ohm featuring 4.3 dBd Gain and a 16dB F/B with a good bandwidth.

VHF UHF half wave flower pot antenna project by VK2ZOI

Crank-up(telescopic) and tilt-over tower, Ring rotator for mounting an extra antenna, from 16m to 42m, Strong safe and smooth, Radio communication and commercial tower.

After you have build this antenna, you may not need anything else. This article shows how to build a VHF j-pole antenna and how to protect it by inserting it into a PVC tube, the correct way.

Thierry Lombry, LX4SKY (aka ON4SKY) has developped a excellent educational website mainly devoted to amateur astronomy but it includes also a large section dealing with amateur radio activities includes several interesting pages about radio astronomy and SETI

Examines the historical role of telegraphy within Canadian railway operations, detailing the evolution of communication systems crucial for train dispatch and coordination. It covers the technical substance of railway telegraphy, including equipment, operational procedures, and the personnel involved, such as agents and operators. The resource provides insights into the **F59PH locomotive** history, development, and components, alongside diagrams of various parts like antennae and traction motors. The content also explores the practical application of these systems by documenting specific railway events, such as the CPR Galt Sub operations from 1895-1971 and GO Transit's operational history. It includes photo galleries, schematics, and diagrams of locomotives and cab cars, offering a visual and technical comparison of different railway equipment. The site also features information on **GO Transit** rolling stock, including MP40s and commuter coaches, providing a historical context for railway communication and transportation.

India Radio Poland web site

Portable electronics, amateur radio, pro audio and digital cameras batteries, chargers and conditioners.

A home made VHF 2.5kw RF power amplifier made with a GS35B Triode and designed by Frank F1CXX built in 2003

A live map of current KiWiSDR receivers available on the network. It allows users to explore a directory of web-controlled receivers for listening to HF and VHF stations worldwide. The site provides access to remote ham radio stations online, making it a valuable resource for amateur radio operators.

3D20CR Official website of Conway Reef DX Pedition 2009

"Shows who is ""active"" on VHF in EI, Solar Auroral and Tropo information, Vhf logs and maps."

Shows which beacon is currently transmitting on the selected radio band Displays information about transmitting beacon Informs about direction and bearing from users position towards transmitting beacon

Free basic and advanced system design tutorials for every component and aspect of solar power. Plus system sizing calculators, battery bank calculators and wire size calculators

Web Morse Runne is an online CW (Morse code) contest simulator developed by DJ1TF - Thomas Fritzsche. This tool allows users to practice their Morse code receiving and sending skills in a simulated contest environment. Key configurable parameters include CW speed, with options ranging from 300Hz to 900Hz, and RX bandwidth, adjustable from 100Hz to 600Hz. Users can also set a monitor level and simulate various band conditions. The interface includes counters for calls and QSOs per hour, along with a timer. Pre-defined function keys are available for common contest exchanges such as F1 (CQ), F3 (TU), F6 (B4), F7 (?), and F8 (NIL). The simulator is designed for ham radio operators looking to improve their CW contesting proficiency.

The article details a specific method for performing maintenance on a crank-up tower, focusing on cable and rotator replacement without a full power pulldown. It outlines the necessary equipment, including a 2-section extension ladder with a horn attachment and a two-piece, 6-foot steel pipe, specifying a 1 1/4-inch diameter. The procedure involves lowering tower sections onto the internal pipe to slacken cables, allowing for their removal and replacement, and also describes how to replace the rotator while the tower remains upright. Key steps involve using the pipe to support tower sections, enabling access to the cables and bearings. The author, N5AR, emphasizes safety by instructing the reader to remain on the ladder at all times, rather than climbing the tower itself. The process is presented as manageable for a single operator, with the author having successfully completed the task on a _UST TX472_ tower. Specific tools mentioned include Allen wrenches and end wrenches for cable ends and bearing bolts. The method provides a practical approach for tower upkeep, minimizing the complexity often associated with such tasks and allowing for maintenance of components like cable pulleys and their bearings.

4CX1500B RF amplifier schematic, working 1.8 MHz to 29.7 MHz

Yaesu FT920 youtube review by Roy Sargon ZL1LK