Search results

This PDF file provides detailed information on HF propagation for ham radio operators. It covers the principles of how radio signals travel over long distances, including factors that affect signal strength and propagation. The content is useful for hams looking to improve their understanding of radio communication and optimize their transmissions. Whether you're a beginner or an experienced operator, this resource offers valuable insights into HF propagation that can enhance your communication skills and efficiency on the airwaves.

The Interlock Monitor (IM) program allows you to control and monitor the Interlock device from any computer in your network. The Interlock is an equipment designed to be used by contesters where they need to check, supervise and limit, how many radios are in transmission at any given time

Single-sideband (SSB) radio enhances spectral efficiency but poses challenges with audio intelligibility, particularly in noisy conditions. A microphone audio compressor addresses these issues by dynamically managing the audio signal’s dynamic range. It amplifies quiet sounds and attenuates loud ones, ensuring consistent audio levels for improved clarity. Benefits include increased intelligibility, higher average power, and reduced spurious emissions. While essential for optimal SSB performance, careful parameter adjustment is crucial to balance natural sound quality and effective communication across various operating modes.

Noise-canceling electret condenser microphones (ECMs) are ideal for compact, battery-powered devices due to their small size, low power consumption, and high sensitivity. These microphones, used in conjunction with active noise cancellation circuitry, significantly reduce ambient noise, creating a more peaceful listening experience by combining and processing signals from multiple microphones.

Learn about Permeability Tuned Oscillators (PTO) and why they are useful for ham radio operators. This page covers the mechanics of PTO tuning, the components involved, and how to wind the PTO inductor. Written by Andrew Woodfield ZL2PD, this resource provides a detailed guide for building and using a PTO oscillator in your amateur radio projects.

This loop antenna is intended to be connected as an antenna for receivers that do not have a built-in antenna such as an HF set or an old tube radio. This square barrel is wound on a wooden frame. It consists of two windings that are galvanically isolated from each other, a main and a coupling winding. The diameter is about 40 cm.

The Big Gun's Guide" is a comprehensive exploration of low-band propagation, aimed at serious Amateur Radio operators. It delves into the complex physics of the ionosphere at lower frequencies, contrasting it with HF propagation. The book covers essential topics like ionospheric fundamentals, propagation mechanisms, magneto-ionic effects, and disturbances. It also addresses the challenges of low-band DXing and provides insights for overcoming them. Brown's work is detailed and technical, offering valuable knowledge for those seeking to master the intricacies of low-band communication

Learn how to hack an IR turret to track the International Space Station (ISS) as it passes overhead. Discover the basics of the ISS and how to use simple tools to point an arrow at the ISS without looking at a phone. Find out how to calculate the azimuth and elevation angles to locate the ISS in the sky and enjoy watching this habitable space craft orbit the earth at a speed of 28,000 km/h. Take your hobby to the next level by bouncing radio signals off the ISS or even talking to the astronauts on board. Turn stargazing into an interactive and educational experience with this fun and practical project.

Multi Mode 70cm DIY Repeater Build Project made with two Tait TM8235 and acting as modem a Repeater Builders MMDVM plus a Raspberry PI

This article presents a novel Top Loaded End-Fed Half-Wave (TLEFHW) antenna design for 20-meter ham radio operation. The antenna features a compact 14-foot vertical radiator with a capacitance hat configuration, eliminating the need for radials or ground systems. Using EZNEC modeling and field testing, the design achieves a 1.5:1 SWR across the 20m band with a 4.11 dBi gain. Key features include quick deployment, lightweight construction, and directional radiation pattern with 110-degree beamwidth. The design, while requiring a 45-foot footprint due to the top hat, offers an effective portable solution for amateur radio operators seeking a no-ground, no-tuner 20m antenna option.

This document provides a comprehensive guide on purchasing high-frequency (HF) high-power amplifiers, discussing key considerations such as new versus used models, tube versus solid-state technology, and troubleshooting common issues. It emphasizes the importance of understanding power needs for activities like DX chasing and contesting, alongside practical tips for selecting and maintaining amplifiers to ensure reliability and performance in various conditions.

Learn how to build your own RF signal generator for aligning radios by following the modifications made to the circuit of an existing project. Explore the use of a common cathode varactor diode and a single center-tapped 24 VAC transformer to simplify the design. Discover alternative components like the MACOM 4ST079CK-287T varactor diode, which offers cost-effective solutions compared to unobtainable options. Find inspiration in modifying existing projects and gaining practical knowledge in electronics. Purchase the Nuts and Volts magazine for detailed schematics and a deeper understanding of RF signal generators.

Effective suppression of harmonics and parasitic radiation from HF transmitters is crucial, especially with the increasing sensitivity of VHF/UHF radio channels to interference. This project details a hybrid low-pass filter (LPF) designed to operate across the HF bands up to 51 MHz, making it suitable for 6-meter band operations while providing deep VHF/UHF suppression. The design addresses the challenge of modern interference landscapes, where even microvolt-level signals can disrupt wireless sensors and other simple VHF/UHF receivers. The filter utilizes a single elliptic link, combining high cutoff steepness with robust suppression in the hundreds of megahertz range. A key feature is the use of only two standard capacitor values, simplifying construction and component sourcing. The article provides a detailed schematic, performance characteristics, and _RFSim99_ model file, demonstrating a reflection coefficient S11 below 0.017 (VSWR < 1.03) across 1-51 MHz, ensuring minimal degradation to the antenna system. Construction notes include coil winding specifications and capacitor selection guidance, with recommendations for _FR-4_ assembly. Two capacitor sets are presented, with the first variant recommended for its lower RF current demands, keeping currents below 3 A at 1 kW passing power at 51 MHz. Fine-tuning involves adjusting frameless coils, with considerations for capacitor tolerance and high-frequency capacitance measurement accuracy.

The history of the radio is a fascinating one that changed how the world connected and communicated from distances both far and near. History of the Radio from Inception to Modern Day

Adding 2 RCA inputs, 1 high impedance filtered audio output RCA 3, 3 HIGH PASS filters, 3 LOW PAS filters to the JRC NVA88 Speaker

Protect your radio tower and solar charged battery power supply by sending the correct Morse code transmissions. Tap out alphanumeric characters in Morse code to prevent your radio station from being destroyed by the Morse code meteor attack! Meteors may be destroyed in any order. All levels start with a fully charged battery. Each DIT uses 1% battery power. Each DAH uses 3% battery power. Your battery charges at a nominal rate of 1% every 5 seconds, and total charge increases by 1% for every correct Morse code transmission. In addition, you have two solar panels that each contribute 1% to the battery charge rate. If your solar panels are destroyed, there are no replacements for that game. When your battery runs low, an SOS prosign bonus appears. Destroy this entity to recharge your battery.

open890 is a web-based UI for the Kenwood TS-890S amateur radio, and features good usability, clean design, and high-speed bandscope/audio scope displays, among other features not available either on the radio itself, or in the ARCP remote control software. It is currently only designed to interface with the TS-890 via a LAN (or wifi) connection, and not a USB/serial connection. It may work with the TS-990, as the command set is very similar, but is currently untested.

Alan (W2AEW) shares his comprehensive portable field radio kit, showcasing various antenna options and accessories for POTA activations. The kit, housed in a repurposed camera bag, features the Elecraft KX2 Shack a Box, AX1 antenna kit, and additional accessories. With thoughtful organization and adaptability, the kit offers flexibility for different deployment scenarios, ensuring efficient operation in diverse field conditions

Chris VK3QB, Luke VK3HJ and Alan VK6CQ will be active from Norfolk Island - IOTA OC-005 14 April - 25 April 2022 (UTC)

Serving Appleton, WI area. Weekly 2M net Wednesday 9:00PM CDT.

The Worked All Britain Awards Group (W.A.B.) was devised by the late John Morris G3ABG in 1969. This was to promote an interest in Amateur Radio in Britain and to sponsor a series of awards based on the geography of Great Britain and Northern Ireland.

Saint Brandon expedition 3B7M 2023. Official web site

This page gives a brief description of a 70 MHz transverter that has been published in the Danish amateur radio magazine "OZ." This way hams outside Denmark may also benefit from the design.

This page presents the Arduino radio receiver project created by EasyEDA in 2024. It includes design drawings, BOM, and project details. The content is aimed at hams interested in building their own radio receiver using Arduino technology. The project is shared under a CC BY-ND 4.0 license, allowing others to replicate and modify it. The page also includes comments from project members, making it a useful resource for hams looking to explore radio receiver construction.

A free educational website offering hands-on battery information. The tutorials evaluate the advantages and limitations of diverse battery chemistries, advise on best choices, and suggest ways to extend life.

A voice keyer for Morse Code written for Arduino

The UV-K5 HF Fullband receive firmware version 0.3 introduces enhanced SSB capabilities using the SI4732-A10 chip. Released separately from UV-K5 CEC firmware, it offers improved HF reception, mode changes, frequency fine-tuning, and user modifications. New PCB designs and detailed usage instructions are included.

Antenna modeling is an essential technique for both amateur and professional engineers, enabling precise analysis of antenna performance. This guide, published on 4 different QST articles by L. B. Cebik, introduces NEC-2, a widely used public domain software for modeling antennas, focusing on its capabilities and practical applications. The series aims to demystify the modeling process, providing foundational knowledge and techniques for effective antenna design. Key concepts include understanding the method of moments and the importance of segmenting antenna elements. By mastering these principles, users can enhance their comprehension of antenna behavior and optimize their designs for improved performance.

Learn how LoRa mode can be used for APRS and connected mode packet radio, offering low power and long-range communication. Discover the growing popularity of LoRa-only APRS devices and the use of LoRa boards from manufacturers like Lilygo, Heltec, and RAK. Find out about firmware options like Ricardo Guzman's CA2RXU firmware, which incorporates previous work and offers KISS for external APRS clients. Explore LoRa APRS frequency and modulation settings in the UK, and consider adding CA2RXU firmware to lora-aprs.live for more radio-specific information. Dive into the world of LoRa technology for ham radio operators and experiment with different firmware options.

If you need a non-standard resistor value you could probably realize a close match using two resistor. If you use two resistor in series it is quite easy to figure out which values give the best match; on the other hand, using a parallel connection it is not so easy (at least for me) to find a good combination. This resistor calculation tool shows which combinations of two resistors (series or parallel) gives a match better than the closest standard value, for the E12 (10%), E24 (5%) and E96 (1%) series.

The Icom series of radios from the IC-746 Pro on to the latest 7800 radios have a 4 memory digital voice and CW keyer built into the radio. This external Keypad, based on the official Icom circuitry can considerably help you on using the voice and cw keyer

The LKJ Wednesday Night Special Antenna, designed by John Whiteman K5LKJ, is a compact 50-foot coil-loaded dipole for 80-meter operation, ideal for space-limited hams in residential areas. Using two 1-inch diameter PVC coils with 87 turns of #16 magnet wire each—placed 10 feet from the center—it tunes to 3.910 MHz for local nets like BVARC Rag Chew. Constructed with #14 wire, ceramic insulators, and Mini-8X feedline, it handles 1000W, performs well at low heights for NVIS, and requires a tuner for bandwidth. Collaborative tuning by club members ensured success.

Come learn why it is very difficult to predict propagation on the top band. Ionospheric Variability, Time Variations of Ionospheric Parameters, Atmospheric Gravity Waves, Ionospheric Absorption and The Role of Negative Ions.

RUssian DXpedition Team is glad to annonce a trip to Kindom of Eswatini (Swaziland).Active on HF Bands 7-22 October 2021

Compare the efficiency of two HF (or VHF) antennas by simultaneously transmitting FT8 on nearly the same frequency and analyzing PSKReporter SNR data. Determine the effectiveness of your new antenna compared to the old one in dB, to several decimal places. Run FT8 on two transmitters with different call signs and equal power, connected to each antenna. AntennaCompare analyzes global signal reports, isolating antenna performance.

Cloverleaf antenna is a circular polarized antenna which is way better than the cheap dipole antenna that comes with video transmitters and receivers. The Cloverleaf is a closed loop antenna which the signal and ground wires are connected. The cloverleaf antenna has 3 loops at 120 degree apart, and they are titled at 45 degree to horizontal plane.

The _DX EXPLORER_ blog serves as a personal chronicle of amateur radio experiences, particularly emphasizing homebrew projects and DIY radio equipment. It provides insights into constructing various transceivers and receivers, such as the Minimalist CW Transmitter and the Sputnik Regenerative Receiver, offering practical guidance for those new to the hobby. The content often details the assembly and operation of low-cost kits like the $3 Pixie Transceiver, demonstrating accessible entry points into radio construction. Beyond building, the site also features reviews of commercial gear, including the Tidradio TD-H8 Radio, providing an operator's perspective on performance and utility. The author, YO6DXE, shares a learning journey, aiming to inspire fellow enthusiasts to engage with the technical aspects of amateur radio. This resource covers a range of topics from basic circuit explanations to practical operating tips, fostering a deeper understanding of radio principles. The blog's focus on personal experimentation and project documentation makes it a relevant resource for hams interested in hands-on learning.

The document provides fundamental information on radio wave propagation and NVIS communication, covering line of sight, surface waves, and ionospheric reflection.<p> It focuses on the Near Vertical Incidence Skywave (NVIS) method for reliable coverage in mountainous or skip zones, especially for regional and emergency communications.

Amateur radio website dedicated to six meters band with dedicated pages on 50MHz propagation and DXing

This website presents ideas regarding the use of High Speed Multi Media as a way to expand networks for emergency response communications and day to day operations.

A blog post about experimenting AI on writing blog post and creating pictures. This page includes also a youtube video by VE4VR experimenting ChatGPT over ham radio bands.

Stampfl ham electronics produces SDR Receiver kits and Morse Keys in small batches and in the usual Swiss Quality

Learn how to build a VHF 144MHz transverter connected to an LMR SDR radio using easily accessible components. The transverter works by mixing the 144Mhz input frequency with a 116 MHz local oscillator frequency. Explore the challenges of finding a 116 MHz crystal and the solution of using a programmable Si5351A oscillator. Follow the provided schematic for the RX and TX sections. The transverter design is still a work in progress, with ongoing trials to achieve optimal results.

Twigger is a very lightweight, free ham radio logger designed for Windows, offering seamless integration with transceivers via _TCI_ or OmniRig. This software stores all logged contacts in a SQLite database, with the flexibility to export daily ADIF files for import into a main logger or to send real-time QSO data via UDP in N1MM XML format. It also supports direct, real-time uploads to popular online logbooks like Clublog and QRZ.com, streamlining the logging process for active operators. The application has seen continuous development, with version 1.1.34 fixing an ADIF log importer bug and earlier versions adding crucial features like WSJT-X/JTDX UDP support. Author OE3IDE, Ernst, has incorporated user feedback, including ideas and testing from MW0LGE, to refine the software. Key enhancements include the transition to SQLite for data storage in version 1.1.32, allowing for easy import of previous Twigger ADIFs upon initial startup. The logger also features integrated DX cluster support, enabling users to send spots directly and query QRZ.com for callsign information, which is then cached to reduce redundant queries. The software's compact design and essential logging capabilities make it a practical tool for casual logging or as a secondary logger during contests, with the ability to handle **25 downloads** for version 1.1.34.

Operating on the HF and VHF bands, the URE WebCluster serves as a real-time DX spotting network for amateur radio operators. It aggregates DX spots from various sources, presenting them with detailed information such as DX callsign, frequency, mode, and spotter details. The platform integrates essential propagation data, including current solar indices like _K-index_ and _A-index_, alongside visual propagation maps, which are crucial for planning long-distance contacts. Users can submit new DX spots, contributing to the collective intelligence of the amateur radio community, and filter existing spots by band, mode, or callsign, enhancing operational efficiency. This resource enables operators to monitor band openings and identify active DX stations, significantly aiding in _DXCC_ pursuit and contest operations. The integration of solar-terrestrial data directly within the cluster interface allows for immediate correlation between propagation conditions and observed DX activity, a feature not universally present in all web clusters. By providing both raw spot data and contextual propagation information, the URE WebCluster offers a practical tool for real-time decision-making during operating sessions, allowing hams to quickly adapt to changing band conditions and target specific _DX_ entities.

5V7RU DX Pedition to Togo online log search provided by clublog

Online log for 7P8RU Lesotho DX Pedition 2021

AllScan is a free and open-source web app for AllStar nodes that provides Favorites Management features, AllStarLink Stats integration, and connection monitoring and control functions. Shows your favorites in a Dashboard summary table with Keyed status, Connected Node count and other statistics. Continually scans the status of each favorite using ASL's Stats API data showing which favorites are active and have recently been active. Allows favorites to be connected with a single click (optionally automatically disconnecting any currently connected nodes first). Allows the Favorites Table to be sorted by Node#, Name, Description, Location, etc. Favorites can be added/deleted simply by entering the node# and clicking a button. These features finally give AllStar nodes similar memory management and scan capabilities that analog radios have had for decades. AllScan is mobile-friendly and optimized for ease of use on both small and large screens. AllScan follows the latest web development standards, with PHP, JavaScript, HTML, and CSS cleanly partitioned, runs on both ASL and HamVOIP, and is very easy to install, configure, and update.

The Belgian Air Force Amateur Radio Association sponsor of BAFARA Award

A custom center hub for a Spiderbeam yagi antenna, enabling side-mounting on an existing mast. Challenges included structural instability, limited reach for assembly, and interference with a pre-mounted Spiderpole. A new hub using 40x40mm aluminum tubing provided strength, allowed side assembly, and supported fiberglass pole guy lines. The solution facilitated efficient installation and removal, delivering excellent performance compared to a SteppIR yagi.