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Excellent guide to build your own G5RV antenna by Lombry

The _Astron RS35m Power Supply Schematic_ provides a detailed circuit diagram for this popular linear power supply, focusing on the rectifier and pass transistor stages. It presents the AC input and DC output sections, illustrating the component layout and interconnections critical for understanding its operation. The schematic is enhanced with specific annotations derived from the December 2005 QST "Hands-On Radio, Experiment #35 Power Supply Analysis." These notes offer insights into the circuit's functionality and potential analysis points, making the diagram more instructive than a bare schematic. The resource serves as a practical reference for hams interested in the internal workings or maintenance of the _Astron RS35m_ unit. This document specifically highlights the key components responsible for voltage regulation and current delivery.

Thierry LOMBRY, ON4SKY, develops in several long articles all you need to know about antennas, their design and performance, for both amateurs and SWL

Some tens of very special audio files recorded during amateur radio activities like aurora traffic, meteor scatter, communications with ISS crew and the sound of various transmission modes that you can hear on HF and VHF bands

Product review & short takes columns from QST magazine

Multi-band centre-fed antenna capable of very efficient operation on all HF bands, specifically designed with dimensions which allow it to be installed in gardens and other open spaces which accommodate a reasonably-straight run of 31.1m (102 ft) for the flat-top standard model.

Thierry LOMBRY, ON4SKY, develops in three long articles all you need to know about amplification, and how to seletc an HF and a solid-state amplifier, with pictures.

Suppliers of Amateur Radio equipment, Antennas, accesories MFJ, Ameritron, Mirage, hardware and software for digital modes.

One of the most important considerations when designing and building a Yagi antenna is the method used to attach the elements to a boom. This is true because the boom influences the electrical length of the elements. In this article JH Reisert explain with drawings techniques on mounting yagi antenna elements to a boom

Interesting review about active magnetic loop antenna Wellbrook ALA 1530 and 330S by ON4SKY

HDSDR is a free SDR (Software Defined Radio) application for Windows. Common usage is Radio listening, Ham Radio, SWL, Radio Astronomy, NDB-hunting and Spectrum analysis. HDSDR (former WinradHD) is an advanced version of Winrad, written by Alberto di Bene I2PHD

Dedicated to building bridges between the EME, SETI and Radio Astronomy Amateur Interest Groups.

Starting point for some basic facts about radio astronomy, what radio astronomers do, how radio telescopes work, and the kinds of research done with radio telescopes.

What You Should Know About Lightning Protection by Joseph H. Reisert

Excel sheet containing technical comparisons of commercial HF portable antennas compiled by ON4SKY. Includes pictures, manufacturer, db gain, band coverage, F/B ratio, price, weight and dimensions.

This workbook was developed to support training for the Goldstone-Apple Valley Radio Telescope, but is a resource applicable to all radio astronomy.

by Dr. D.T. Emerson, National Radio Astronomy Observatory (NRAO++). Antenna Compendium Volume 4, pp 64-68, 1995, published by the ARRL.

SATBUSTER for Windows is especially designed for satellite visual observers and trackers. Its users, mainly amateur astronomers and radio amateurs, appreciate both the accuracy and the simple to use graphical interface.The software is aimed to hobbysts. However a growing number of plain folks are starting to use this tool to recognize and look at the International Space Station and the Space Shuttle during its missions too

Astron corporation power supplies and accesories

MSDOS astronomical clock and celestial tracking program with navigation features

A complete review of Icom IC-706 review published in 1999 by QST

Comprehensive astronomy / space / satellite-tracking package for Microsoft Windows 95/98/Me and Windows NT 4.0/2000/XP

This page will help you answer important questions about antenna selection before you talk to a supplier. After reading this paper, you should be able to better determine the most important parameters you need to know for your antenna selection criteria.

Russian callsign prefix series: RAA-RZZ, UAA-UIZ, includs Amateur callsign system in Russia

Ballistic simulator "Orbit" allows the physical principles of the motion in the gravitational field of the Earth to be demonstrated and learned. You can calculate with this program the ballistic trajectories of the thrown bodies and orbits of spacecrafts and visualize the astroballistic situation on the flat map of the world and on the rotating globe in the real time

SARA is a dedicated group of people that formed an international society to learn, trade technical information and do their own observations of the radio sky

Technical and modification information on Astron Power Supplies compiled from a number of different sources by Mike Morris WA6ILQ

Thierry LOMBRY, ON4SKY, develops in several technical articles the way to select a transceiver. His website includes also some in-depth reviews

FREE specialized software in the detection and registration of echoes radio products by meteors shower, falling star, at the time of their gone in atmospheric. They are destined to all possessors of a radio and a computer, interested parties by this simple technique of radioastronomy.

Echos of USAF (Formally NAVSPASUR) radar signals reflected off of meteor trails received at Roswell, New Mexico

Amateur radio-telescope project of a retired seafarer.

Thierry LOMBRY, ON4SKY, develops in several long articles the bascis of propagation. His website includes also a French section dealing with auroras.

Supplier of Radio Telescopes and associated equipment since 1994.

The Yaesu FT-1000MP Mark-V, introduced at Dayton 2000 Hamvention, features a higher RF power of **200 W PEP** and a Class-A amplification SSB mode at 75 W. Key enhancements include an _Interlocked Digital/Analog Bandwidth Tracking system (IDBT)_, a Variable Front-End Filter (VRF) preselector, and improved ergonomics, notably a multi-function shuttle jog dial. This model, a successor to the 1996 FT-1000 and FT-1000MP, was designed to compete with high-end transceivers, despite its retail price of $4200 initially. The transceiver's physical dimensions are 406 x 135 x 348 mm (16 x 5.3 x 13.7 inches) with a weight of 14 kg (31 lbs), making it substantial. Its rear panel offers over 20 connections, including power, external DSP speaker, BAND DATA I/O, ALC, and multiple interface jacks for DVS-2, Packet, and RTTY. The unit also provides two keyer inputs, a DB9M serial interface for CAT, and two PL female antenna connectors, plus additional receive antenna jacks. Despite its advanced internal architecture, including two independent receivers with their own IF filters and AGC loops, the display technology, utilizing fluorescent discharge rather than LCD, contributes to an older aesthetic. The control panel is extensive, featuring 92 knobs and buttons, alongside numerous LED indicators for various modes and functions.

The Kenwood TS-570D(G) transceiver (I), by Thierry Lombry, ON4SKY

Amateur radio shop in Barcelona Spain

What become our QSL once sent ? QSL routes, IRC and green stamps, the best and worst practices.

Whith more than 20 years of ham practicen SWL Thierry LOMBRY, alias ONL5183, has written several technical pages about ham activities, including propagation, radio perturbations, radioastronomy, DXing, QSLing, ham-spirit, review of material and more. This very interesting website is completed by a large French section devoted to amateur astronomy illustrated with vivid colors pictures.

Amateur Radioastronomy in Poland

Over 130 years after its inception, Morse Code remains a fundamental skill for many amateur radio operators, enabling efficient QRP operations, DXing, and contesting. This resource provides an in-depth look at the **Koch Method** of Morse training, a widely adopted technique that emphasizes high-speed character recognition from the outset. It details how this method can significantly accelerate proficiency, moving beyond traditional, slower learning approaches. The site also delves into the rich history of amateur radio, presenting articles such as "Radio on the Rio," which chronicles local ham activity in Socorro, New Mexico. Another piece, "The Russian Woodpecker," recounts the Cold War-era efforts of hams to counter Soviet over-the-horizon radar interference on the HF bands. Furthermore, the resource explores the fascinating intersection of ham radio and radio astronomy, highlighting the direct lineage between amateur experimentation and the development of modern radio telescopes like the **Very Large Array (VLA)**. It also includes an introduction to the 6-meter band, often called "The Magic Band," detailing its unique propagation characteristics and suitability for no-code licensees seeking long-distance contacts.

Resources for amateur radio astronomers, teachers, and students.

In his back office section, ON4SKY, initiates in a few articles the beginners in the art of QSLing and award chasing.

The GM4JJJ VHF and EME pages document David's extensive work in Earth-Moon-Earth (EME) communication, specifically on the 144 MHz band, and his involvement in amateur radio astronomy. The resource details his station setup and operational experiences, providing insights into the technical challenges and rewards of bouncing signals off the moon. It offers a glimpse into the specialized equipment and techniques required for successful EME contacts, a niche but highly rewarding aspect of amateur radio. David's content shares practical applications and field results from his EME endeavors, which can be particularly useful for hams contemplating or actively pursuing moonbounce operations. The information, while not a step-by-step guide, implicitly compares the complexities of EME with more conventional VHF/UHF operations, highlighting the significant power and antenna gain necessary to overcome path losses. This resource serves as a testament to the advanced capabilities achievable in amateur radio.

Protecting amateur radio equipment from transient overvoltages requires robust lightning and surge protection, which is the focus of Electronic Specialty Products. The company provides various devices, including coaxial lightning arrestors for antenna feedlines and surge protectors for AC power lines and data circuits. These devices are engineered to divert high-energy surges, such as those caused by direct or indirect lightning strikes, away from sensitive transceivers, amplifiers, and computer components, thereby preventing catastrophic damage. Key products include the _Coaxial Lightning Protector_ series, designed for various impedance levels and frequency ranges up to 3 GHz, and the _AC Line Surge Protector_ for shack power distribution. Effective deployment of these protection devices can significantly reduce the risk of equipment failure and ensure operational continuity during severe weather. For instance, a properly installed coaxial arrestor can handle peak currents of **20 kA**, while AC line protectors offer clamping voltages typically below 400V. Comparing different models reveals varying levels of insertion loss and return loss, with some coaxial units exhibiting less than 0.1 dB loss at 500 MHz, making them suitable for high-performance HF and VHF/UHF operations. Integrating these components into a comprehensive grounding system is crucial for achieving maximum protection against both common-mode and differential-mode surges.

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

This page presents a curated list of individuals who have made significant contributions across various fields while also being active amateur radio operators. For instance, Dr. Joseph H. Taylor, co-winner of the 1993 Nobel Prize in Physics for the discovery of binary pulsars, is recognized for developing the _WSPR_ and _WSJT_ weak signal mode software. Similarly, Wilson Greatbatch, inventor of the cardiac pacemaker with over **150 patents**, is featured. The resource details the diverse backgrounds of these hams, from Professor Donald H. Menzel, an astrophysicist at Harvard, to Hiram Percy Maxim, often called "The Father of Amateur Radio," who also pioneered in the automobile and aviation industries. King Hussein of Jordan, JY1, is noted for his active participation on 20 meters, engaging with fellow amateurs like Pat Kilroy, WD8LAQ. Other entries include Arthur M. Young, designer of Bell Helicopter's first model, and Marlon Brando, KE6PZH/FO5GJ, known for operating from his private island in French Polynesia. Peggy Sue Gerron-Rackham, K5PSG, gained her license after a special event station, demonstrating the hobby's broad appeal.

Thierry LOMBRY, ON4SKY, gives advice to amateurs about lightning protection of an hamshack, including pictures and links.

Magnetogram, Dopplergram Intensitygram by Mt. Wilson 150-Foot Tower Data Images

Radio astronomy research at the University of Calgary

Site dedicated to amateur radio astronomy, providing information on Earth-Moon-Earth (EME) communication, the Search for Extra-Terrestrial Intelligence