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Go portable with an external battery pack. The built-in batteries will not last thirty minutes when transmitting, that's not really practical. An external battery pack overcomes these problems.

A free web app that converts ADIF files into KML format for viewing on Google Earth or other KML viewers. Users can view QSOs on a 3D globe, click on station markers for details, and navigate the globe. The page provides instructions, features, limitations, and requirements for using the tool.

This page allows hams to design a vertical-plane delta-loop antenna for a single amateur HF band in different configurations. By choosing different feed-point positions, operators can observe variations in polarization properties, radiation patterns, and feed-point impedances. Users can generate radiation pattern plots, VSWR charts, antenna current diagrams, and Smith charts for their antennas over various ground types. Through adjusting the antenna's physical dimensions and refreshing the plots, hams can gain insights into the antenna's performance in the field. The page also discusses how elevation radiation patterns may change based on the antenna configuration and feed-point position.

A small magnetic loop antenna, often employed by hams facing antenna restrictions or high local RFI, offers a compact solution for HF operation. This resource details the construction of a foldable magnetic loop designed for the 40m through 17m bands, emphasizing its high-Q factor and _Faraday coupling_ for effective noise rejection and narrow-band filtering. The guide outlines material selection, advocating for copper over aluminum to maximize efficiency, and provides insights into the physics governing its operation, including impedance matching and resonance principles. Practical application of this antenna design is particularly beneficial for QRP enthusiasts and portable operators seeking a stealthy, high-performance antenna. The construction process includes specific details for a 1-meter diameter loop, a 140pF variable capacitor, and a _gamma match_ for impedance transformation. Performance comparisons suggest that while a full-size dipole might offer slightly better gain, the magnetic loop's ability to mitigate local noise often results in a superior signal-to-noise ratio, making it a viable option for challenging RF environments.

Quisk is a Software Defined Radio (SDR) and is the software that controls my receiver and transmitter. Quisk can control the HiQSDR, Hermes-Lite hardware, SoftRock hardware, SDR-IQ by RfSpace

A DIY cantenna can extend your WiFi range by building a 2.4 GHz high-gain antenna using accessible materials. The design, based on waveguide principles, uses a cylindrical tube to capture WiFi signals and can even connect to access points half a mile away in ideal conditions. While the ideal tube diameter was hard to find, a 4-inch aluminum dryer vent was chosen despite theoretical limitations. The cantenna offers a cost-effective, functional boost for your wireless network.

The QRP Cluster provides a dedicated platform for _QRP_ (low power) amateur radio operators to self-spot their on-air activity. This web-based service allows users to post real-time information about their current operating frequency, modulation mode, equipment used, and transmit power. It facilitates QRP-to-QRP contacts and helps other low-power stations locate active QRP signals across various bands. Unlike general DX clusters, the QRP Cluster focuses exclusively on low-power operations, fostering a community for QRP enthusiasts. It enables operators to share details such as **5 watts** or less output, often specifying antenna types or unique portable setups. The platform supports the discovery of QRP stations for casual QSOs, contests, and award hunting, enhancing visibility for stations that might otherwise be overlooked on higher-power clusters.

The author describes his experience building and using a Beverage antenna for the 40-meter band. Despite encountering some challenges, the antenna offered some improvements in receiving stations compared to a 3-element inverted Vee antenna. The Beverage antenna showed a significant daytime signal-to-noise ratio improvement and received signals better than the Vee antenna. However, the front-to-back ratio was not ideal, and the transmit power seemed to affect the Beverage antenna. Overall, the author concludes that the Beverage antenna might be more suitable for locations with higher noise levels. The total cost of the antenna was around 30 Euros.

Presents a dynamic platform for real-time amateur radio contest scoring, enabling participants and enthusiasts to monitor ongoing competition results. The system processes submitted contest data, displaying live scores and competitor standings as they update. Users can observe the progress of various contests, gaining immediate insight into the competitive landscape. This resource serves as a central hub for following _DX contests_ and other operating events, offering a transparent view of current standings. It facilitates an engaging experience by providing up-to-the-minute score updates, reflecting the intensity of _on-line contesting_ and the efforts of operators globally. The platform's utility extends to both active participants submitting scores and observers interested in the competitive dynamics. It aggregates data from multiple sources, presenting a consolidated view of contest activity. The system's design emphasizes rapid data processing and clear presentation of results, crucial for high-stakes events like the _CQ World Wide DX Contest_.

This article discusses the potential for solar power systems to coexist harmoniously with amateur radio, challenging the notion that they are inherently incompatible. Drawing from personal experience, the author emphasizes the importance of selecting RF-quiet components, focusing on series-string Sunny Boy grid-tie inverters. The article also highlights considerations for system design and limitations based on roof orientation, shading, and array size. Overall, it presents a valuable perspective on creating a radio-friendly solar PV setup.

This page provides detailed information on the 4DX directional wire beam antenna designed by LZ1AQ, LZ1ABC, VK6LW, and DD5LP. It explains how to create this antenna for single or multiple bands using four separate sloping wires. The page includes instructions on achieving directionality, gains, and F/B ratios, as well as generating radiation patterns, VSWR charts, antenna currents diagrams, and Smith charts. It is a valuable resource for hams interested in building and optimizing their own directional wire beam antennas for improved performance and long-distance contacts.

The Smith Chart, named after its inventor Phillip H. Smith, is a graphic tool used to solve transmission line problems in the field of ham radio operations. By using the Smith Chart, ham radio operators can determine the feed point impedance of an antenna, design impedance-matching networks, and optimize power transfer between a source and its load. The chart consists of resistance and reactance circles, providing a visual representation of complex mathematical relationships related to transmission line operations. Understanding and utilizing the Smith Chart is essential for hams looking to enhance the performance of their RF circuitry.

This article addresses the issue of unwanted RF in amateur radio setups and introduces a practical method to measure common-mode currents (CMC) using a homebuilt RF meter. The meter, constructed with readily available materials, measures unwanted RF on the coaxial cable shield by inductively coupling to the shield using a split-bead ferrite. The article provides detailed instructions on building the meter, interpreting measurements, and using ferrite chokes to mitigate RF interference. Emphasis is placed on the importance of verifying CMC levels and installing chokes to improve equipment performance.

Use this form to generate a list of amateur repeaters and broadcast transmitters to your specifications. The database covers the fifty U.S. states, the District of Columbia, and the ten Canadian provinces.

Online interactive elevationmap can help radio amateurs by predicting signal propagation, optimizing antenna placement, planning coverage, ensuring line-of-sight, mitigating interference, and enhancing emergency communication. T

The most basic form of repeater receives communication on one frequency and re-transmits it on a different frequency, a process known as duplex communication. This capability significantly extends the range of handheld and mobile radios, as repeaters are typically situated at elevated locations with high-gain antennas and greater transmit power. Repeaters commonly operate with FM modulation on the VHF (30 MHz – 300 MHz) and UHF (300 MHz – 3 GHz) amateur bands, which are ideal for portable and mobile devices. Access to repeaters is often controlled by a CTCSS or PL tone, an inaudible signal that prevents the repeater from retransmitting background noise. This mechanism ensures efficient use of the frequency and prevents illegal continuous transmission. Canadian regulations, for instance, require an Advanced amateur radio license and an available frequency within the band to set up a repeater, each assigned a unique call sign and transmit frequency. Configuring a radio for repeater use involves knowing the repeater's transmit frequency, its receive frequency offset (e.g., -600 KHz for VHF or +5 MHz for UHF), and the necessary CTCSS tone. The article references resources like Repeater Book for locating repeaters and provides practical examples for initiating and concluding a basic repeater session, emphasizing clear identification and concise communication.

This Arduino project explores long-range RF communication using EBYTE E32 1W LoRa modules (either E32-915T30D or E32-900T30D) paired with ESP32 microcontrollers featuring OLED displays. The setup leverages the modules' Semtech SX1276 chip with amplifier to achieve up to 1W transmission power—significantly more than the chip alone provides. Unlike other LoRa implementations, these modules include a microcontroller that simplifies interface through UART rather than SPI. The documented implementation includes proper wiring between components and Arduino code that configures the module, displays received messages on the OLED screen, and transmits messages every two seconds while keeping power consumption manageable.

A two tone generator is an essential test gear made with just four transistors that helps you evaluate your amplifiers, mixers, receivers for distortion. Distortion makes all the difference between a pleasant receiver and a horrible sounding one, between a clean transmitter and bad, splattering one on air.

The Homebrew uSDX SDR TRX is an experimental transceiver primarily designed for CW and Digital modes due to limitations in meeting FCC requirements for SSB. Developed from the QRP Labs QCX, it incorporates advanced SDR features while utilizing an 8-bit ATMEGA328P. The µSDX community fosters open-source development with various design streams and versions, encouraging collaboration and sharing among enthusiasts.

Learn how to build a compact and efficient HF antenna for ham radio operators with limited space. Follow the author's journey from experimenting with different antennas to creating a magnetic-mounted antenna that covers 7MHz to 30MHz without the need for an ATU. Discover how a portable flagpole can be repurposed for radio communication, allowing you to operate with 100 Watts power output. This project provides a cost-effective solution for hams looking to set up a reliable antenna on their car roof in just 30 seconds.

The Shrunken Quad antenna is a unique design that offers full-sized performance on the 10m and 15m bands while incorporating linear loading via a trap for operation on the 20m band. This design allows for effective communication in the HF spectrum, making it suitable for both casual operators and serious DXers. The quad configuration provides excellent gain and directivity, which is beneficial for contesting and long-distance contacts. Constructing the Shrunken Quad involves careful attention to dimensions and materials to ensure optimal performance. The antenna's compact nature makes it an excellent choice for limited space situations, allowing operators to enjoy the benefits of a quad without the need for extensive real estate. This project is ideal for amateur radio enthusiasts looking to enhance their station's capabilities with a versatile and efficient antenna system.

Chokes and isolation transformers are essential for receiving antennas to mitigate common mode current, which induces noise and interferes with signal quality. Common mode chokes, formed by winding feedline through ferrite cores, block unwanted current effectively. Proper selection of core material and winding turns ensures resonance near the operating frequency, reducing interference. Isolation transformers further minimize interference, crucial for multi-transmitter stations.

Morsle.fun is a user-friendly web application designed for practicing Morse code reception by guessing transmitted text, which can be either words or call signs. Users can adjust the volume and tone frequency of the Morse code playback. The application tracks performance and generates activity statistics. Call signs are typically more complex than words, containing up to six characters and at least one digit. Users can practice Morse code at speeds ranging from 10 to 60 wpm.

This project addresses the need for a 50 MHz Amplifier providing substantial power for Australian "Advanced Licensees" permitted to use 400W PEP in the 52-54 MHz band. In regions limited to 100W PEP due to TV channel usage, this initiative aims to enhance power output for transceivers with lower capabilities on the 6m band.

The PicoFox is a versatile fox transmitter for 2-meter ham radio operators, built around the RP2040 microcontroller. With open-source hardware and software, it can be customized to suit your needs, from APRS to other digital modes. This fully assembled transmitter comes with a rechargeable battery and antenna, ready for use. The design allows for easy addition of features like sensors or interactivity. Modulation is handled in software for smooth FM output, with ample CPU, flash, and GPIO available. Configure your PicoFox by connecting it to a computer via USB and adjusting settings in a text file. Explore the possibilities of this innovative transmitter for your amateur radio projects.

This blog post documents the author's journey building an APRS micromodem for amateur radio applications. Using an open-source design by LY2EN, the author assembled a cost-effective Terminal Node Controller (TNC) with SMD components, an Arduino Nano, and a JDY-31 Bluetooth module. The construction process included PCB fabrication, careful component soldering, microcontroller programming, and Bluetooth configuration. A custom 3D-printed case protected the completed device. Field testing in Romania showed the device functioned with a Baofeng UV-5R radio, though antenna limitations affected performance. The entire project demonstrates an affordable DIY alternative to commercial APRS trackers.

This article details the development of an 80-meter antenna within the confines of a restrictive covenant community. Faced with limited space, the author explores various options before implementing a clever hybrid design: a short 30-foot vertical wire running discreetly down the building's exterior combined with a capacitive top hat installed in the attic. Computer modeling confirmed the superiority of capacitive loading over inductive loading, increasing radiation resistance from 6 to 14 ohms. The perimeter wire top hat, naturally supported by the attic structure, resonates effectively at 3.5 MHz. The system is completed with four buried 60-foot radials installed "after dark" to maintain compliance with community restrictions.

In this tutorial, the author shows the basics of how to set up a Raspberry Pi Pirate Radio utilizing the FM Transmitter software and a piece of wire.

The recognition of telegraphy masked by noise at 40 and 80 signs/min telegraphy speed was studied in 10 normal-hearing subjects at different sound pressure levels (25-85 dB SPL in steps of 5 dB) as well as at different test frequencies (2000, 1000, 800, 630, 500 and 250 Hz). The ability to recognize the signs varied with varying SPL. Recognition for most of the subjects was best at an SPL close to 70 dB. All subjects improved their recognition as the frequency was lowered to 500 Hz, some even at 250 Hz. These facts should be taken into consideration when training telegraphy operators as well as in the construction of radio receivers to permit listening at low frequencies. Furthermore, the critical ratio was calculated at the different test frequencies.

During radio's early days, high frequencies were under 30 MHz due to technical limitations. As understanding grew, components improved, allowing for higher frequencies like VHF and UHF up to 3 GHz. The HF band's long wavelengths provide unique propagation challenges influenced by solar activity. VHF and UHF bands face diffraction and reflection issues but offer diverse applications, from amateur radio to 5G and GPS technologies.

WB5NHL describes setting up a 160-meter antenna on a small suburban lot, where standard options like Beverage antennas and 1/4 wavelength verticals require extensive space and ground systems. Instead, Guy Olinger's Folded Counterpoise (FCP) provides a solution. The FCP minimizes ground losses by using a folded wire design, allowing effective antenna placement in limited space. The FCP, fed with an isolation transformer, enabled WB5NHL's first 160-meter antenna installation, offering improved performance despite space constraints.

MorsePractice is a Java application originally written by Martin Minow (K6MAM) as an aid to learning Morse code. With morse practice you can select the digits you want the app to be transmitted. Additionally can be selected a random phrase, or random QSO.

In this article, VE9KK discusses the various restrictions faced by ham radio operators when it comes to setting up antennas. The author shares personal experiences and tips on how to overcome these challenges, providing valuable insights for fellow hams. Whether you're dealing with space limitations or neighborhood regulations, this resource offers practical solutions to help you get the most out of your ham radio setup.

This article published on QEX details measurements of tree conductivity and permittivity at HF frequencies, addressing a long-debated topic in amateur radio. N6LF conducted experimental impedance measurements on Douglas fir and maple trees using a vector network analyzer with rings of nails inserted into tree trunks. Results showed that tree conductivity increases with frequency while relative permittivity decreases, similar to soil characteristics. Measured conductivity ranged from 0.06 to 0.4 S/m at 10 MHz, aligning with values used in previous research. These findings validate that NEC modeling can reliably estimate trees' substantial impact on HF antenna performance.

QRP is a way of operating that involves using low power transmitters, that are no more than 5 Watts for Morse or data modes, or 10 Watts pep for voice. Introduction to QRP operations

A detailed guide presents a simple 2-element quad antenna for 2m, offering ease of construction, portability, and efficient performance across the 144-148 MHz band. The design allows quick disassembly for storage and features adjustable polarization, making it ideal for various applications, including transmitter hunting and SSB operations.

In this study, the author builds upon Muncy's research, demonstrating that radio-frequency current on cable shields affects audio systems through the "pin 1 problem" and shield-current-induced noise (SCIN). An enhanced equivalent circuit for ferrite chokes is proposed, addressing dimensional resonance and inductor self-resonance. Field tests confirm that chokes reduce interference across 500 kHz to 1,000 MHz. Guidelines for diagnosing and mitigating EMI from various sources are provided for product development and field installations.

Analyzes the operational dynamics of the _IARU R1 VHF contest_, the world's largest 2-meter contest, focusing on factors enabling top performers to maintain consistent results amidst declining overall activity. The resource investigates the physical constraints that limit higher point totals, examining how technical capabilities, increased interference, and evolving station setups contribute to contest outcomes. It provides insights into the strategic and technical aspects of achieving high scores, such as the **1,000,000+ point** totals observed from leading stations. Compares the performance of various stations over time, highlighting the sustained success of top contenders and speculating on future trends in VHF contesting. The analysis delves into specific operational strategies and equipment choices that differentiate high-scoring stations, offering a detailed look at the competitive landscape. It also considers the impact of propagation conditions and operator skill on final scores, providing a comprehensive overview of the contest's intricate mechanics and the pursuit of maximum QSO points.

**APRS TX I-Gate with APRX and the Universal Radio Controller** This project explores the creation of an APRS TX I-Gate to improve message delivery in amateur radio communications. Initial experiments involved configuring a picoAPRS v4 and later a G1LRO Universal Radio Controller (URC) with a Quansheng UV-K5 as digipeaters. While both setups successfully retransmitted signals, they failed to receive incoming APRS messages. To address this, a Raspberry Pi Zero running Debian and APRX-2.9 was repurposed to provide network connectivity, transforming the URC into an effective TX I-Gate for seamless APRS message handling.

Learn how to build a simple transmitter called the 'Easy Ten' that can be easily heard at a distance of 10 miles using a random length wire antenna thrown into a tree. This article focuses on working with frequencies in the 3.5 and 7 MHz range without the need for complex setups like coax lines or baluns. The author shares their experience of making contacts across the Pacific Ocean and the United States using just one watt of output power and simple antennas. Discover how to optimize signal output using a homemade level meter made from a DC microameter and a germanium diode.

The Beverage on Ground (BOG) antenna offers ham radio operators a compact alternative to traditional Beverage antennas, requiring less space and fewer support structures. This implementation, optimized for 1.8-7 MHz bands, describes ideal parameters: lengths of 60-90 meters, height of 2-10 cm above ground, and specific load resistances based on configuration. The article details experimental methods for determining optimal load resistance and presents matching systems to convert BOG impedance to 50 ohms. While less effective than classic 200-300 meter Beverages, the BOG provides directional reception in limited space, though performance varies with ground conditions and weather changes.

The article explains how to adapt the YAESU FT817 transceiver so that it can be used to control Kuhne electronic transverters by transmitting at +12V via the coaxial wire. Different FT817 versions imply that some of the modification proposals that have been made so far don't apply to everyone. This tutorial provides a workaround that works with all FT817 models. It makes use of the external ACC socket, connecting an interior tiny circuit board to two thin wires. Follow ON7WP's instructions for using the rear antenna socket.

An **Arduino LC Meter** provides an accessible solution for precisely measuring inductance and capacitance values, crucial for RF circuit design, filter tuning, and troubleshooting in amateur radio applications. This project details the construction of a low-cost, accurate instrument using readily available components, making it an attractive alternative to commercial units for hams and electronics enthusiasts. The build process involves assembling a resonant circuit, integrating an Arduino microcontroller for frequency measurement, and displaying results on an LCD. Key components include an Arduino Uno, a 16x2 LCD, a 74HC14 Schmitt trigger inverter, and a few passive components. The design leverages the Arduino's processing power to calculate L and C values from resonant frequency shifts. Calibration procedures are outlined to ensure measurement accuracy, which is vital for critical RF work. The project includes schematics, a parts list, and the necessary Arduino code, enabling hams to construct a functional LC meter for their workbench.

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

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 resource details the construction of a 433 MHz LoRa APRS iGate and a tracker, both built around _TTGO T-Beam v1.1_ microcontroller boards. Each board integrates an OLED screen, WiFi, GPS, and an SMA antenna connector, powered by an 18650 3.7 V lithium-ion battery or microUSB. The iGate operates on 433.775 MHz, with its status verifiable on aprs.fi, demonstrating practical implementation of LoRa-based APRS solutions. The methodology involves programming the modules using Visual Studio Code with the PlatformIO plugin. This process loads the necessary firmware and a JSON configuration file, which includes the operator's callsign and WiFi credentials for the iGate. The guide emphasizes the ease of programming and provides specific steps for configuration. Initial testing of the iGate and tracker, including smart beaconing configuration, is documented. The low power output of approximately 200 mW from the LoRa board's transmitter is noted, with suggestions for range extension through improved antennas or RF amplification. The author, N4MI, plans to deploy a higher-gain 70cm antenna for the iGate.

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.

This article details the design and construction of a compact 20-meter QRP SSB transceiver by Pete Juliano, N6QW, measuring just 2 x 4 x 2 inches—small enough for a shirt pocket. Inspired by a 1963 QST design and refined from a prior version, it employs bilateral circuits, a 4.9152 MHz homebrew crystal filter, switched-crystal VXO for 60 kHz coverage (14.160-14.220 MHz), and standard components like ADE-1L mixers and IRF510 PA for 1W output. Key innovations include a double-sided PCB skeletal frame for shielding and isolation, Vectorboard sub-assemblies, and ultra-miniature relays. The bilateral receiver/transmitter shares stages, omitting AGC for simplicity, while a W3NQN LPF and optional 10W external amp enable DX contacts. Tune-up focuses on crystal matching and bias for linearity. Videos on YouTube demonstrate performance, confirming excellent stability and audio. Total cost nears $100, prioritizing portability over features like CW.

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.