Search results

This comprehensive three-part guide examines baluns (balanced-to-unbalanced devices) and their critical role in ham radio antenna systems. The author explains how baluns prevent common-mode currents on feedlines, which can distort radiation patterns and cause unwanted RF in the shack. Various balun types are analyzed, including coiled coax chokes, ferrite-core designs (W2DU), and toroidal-wound versions (Guanella/Ruthroff). Construction techniques for 1:1, 4:1, 6:1, and 9:1 current baluns are provided with practical guidance on wire selection, winding methods, and ferrite core properties. The article emphasizes that proper balun implementation is essential for optimal antenna performance, especially with directional arrays.

The document provides a detailed modification guide for the Zetagi HP201 SWR Wattmeter, converting it for HF amateur band usage. It replaces the original circuit with a Tandem Coupler based on the Sontheimer and Frederick directional coupler patent, enhancing accuracy and sensitivity. Key components include Murata toroid cores, scaling resistors, and a new calibration process. Challenges and solutions during the modification process are discussed, ensuring linear results across 160-10m bands. This guide also includes calibration instructions and theoretical insights into the coupler's operation.

This page provides information about building a Beverage antenna for hams. The article discusses using a 60m wire on the ground to create an effective antenna for amateur radio operators. Learn how to set up and optimize this type of antenna for better reception and communication. This describes a low-noise receiving Beverage antenna setup for low bands, using a N30 cup core transformer for 1:4 impedance matching (likely 50:200 Ohm), RG-58 feedline with heavy common-mode choking, and conduit for wire burial.

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.

The resource discusses antenna families frequently utilized by _Parks On The Air_ (POTA) activators, focusing on the specific requirements for portable operations. It highlights the need for lightweight construction, rapid deployment, and sufficient efficiency to achieve the minimum **ten contacts** required for activation. The guide addresses adaptability to diverse field conditions, including the presence or absence of trees and varying ground surfaces. For each antenna type, the article provides a principle diagram, outlines its operational strengths, and details its inherent limitations. It also includes external links to practical field experiences, offering real-world context for each design. The POTA program, which involves setting up a complete station in a park, often within **thirty minutes**, underscores the antenna's critical role in successful activations.

Wavelog, a web-based amateur radio logbook application, launched in February 2024, represents a significant fork from the established Cloudlog platform, developed by a core team including DF2ET and DJ7NT. This open-source project focuses on delivering advancements in both stability and functionality, specifically tailored for the amateur radio community. The application allows users to manage their radio logs from diverse environments, including professional servers, standard web hosting, or even compact _Raspberry Pi_ setups. The platform distinguishes itself through its emphasis on simplicity, robust features, and versatile accessibility, enabling operators to log contacts from virtually any location. It supports various operating modes and data formats, providing a flexible solution for tracking QSOs and managing station activities. The project's development is driven by the collaborative spirit of the amateur radio community, prioritizing utility and user experience over commercial objectives. Key features include comprehensive logging capabilities, support for multiple bands and modes, and integration with common amateur radio data standards, ensuring broad utility for DXers and contesters.

The resource details the construction of a J-pole vertical antenna specifically engineered for motorcycle mounting, addressing the common issue of interference with top cases. It outlines the fabrication process, beginning with an aluminum angle bracket for secure attachment to the lateral support, followed by the creation of the antenna's base from an 8mm threaded rod bent into a U-shape, approximately **40mm** wide. The article specifies the precise method for coaxial cable connections using eyelets and 3mm screws, ensuring robust contact. Further construction steps involve fitting a 10mm aluminum tube onto the threaded rod, with a screw securing the radiating element and establishing core contact. The design prioritizes mechanical stability against vehicle vibrations over fine-tuning SWR with sliding collars. Initial testing yielded a _SWR_ of **1.2** across a significant portion of the band, with improvements noted by optimizing the coaxial braid contact point near the support bracket. The document provides practical insights into material selection and assembly, emphasizing durability for mobile operation. It concludes with aesthetic options, allowing the builder to paint the antenna or retain its natural aluminum finish, making it a functional and adaptable solution for UHF motorcycle communications.

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_.

Illustrates the construction of a mini ununtenna, focusing on practical design elements and component specifications for amateur radio operators. The guide covers the winding of the unun transformer, selection of appropriate ferrite core material, and integration of the radiating element. It specifies wire gauges, core dimensions, and connection points, providing a clear pathway for replication by hams. Compares the ununtenna's performance characteristics against other common wire antennas, highlighting its compact footprint and broadband capabilities. It discusses impedance matching considerations and offers insights into optimizing the antenna for various HF bands, making it suitable for portable operations or limited space installations.

Demonstrates practical **rules of thumb** for selecting and utilizing ferrites and coils in amateur radio projects, particularly for RF applications up to 30 MHz. It addresses common challenges like determining appropriate ferrite grades and estimating L/C values without precise specifications. The resource details the author's experience with readily available grey ferrites, noting their suitability for HF work, and provides guidance on constructing **baluns** and RF chokes, balancing inductance for lower frequencies against inter-wire capacitance for higher frequencies. It also outlines a method for estimating power handling based on ferrite weight, suggesting a 1-gram ferrite can manage over 2 Watts, and offers a technique for evaluating unknown ferrites by winding 10 turns and measuring resonance with a 1 nF capacitor. This approach emphasizes a hands-on, iterative method for balun winding and adjustment, allowing operators to quickly approximate component values. The article compares the characteristics of ferrite-cored coils with air-cored coils, highlighting the reduced pickup and radiation of ferrite designs. It refines the air-coil estimation method for frequencies between 2.5 MHz and 10 MHz and provides a scaling factor for frequencies outside this range, aiming to get operators into the correct general area for their designs. The author's standardized ferrite choice (RND Components 165-00182) is presented as a practical example for reproducible projects.

Four _Headway 38120_ LiFePO4 cells form the core of an 8AH 12V battery pack, designed for reliable emergency and field power in amateur radio operations. These batteries offer significant advantages over traditional lead-acid types, including a lifespan up to **10x** longer in charge/discharge cycles, lower internal resistance for faster recharging, and a flatter discharge curve that maintains voltage stability during use. Their inherent safety, being a flame-retardant technology, makes them a preferred choice for portable applications. Proper configuration, including parallel/serial setups, and careful charging/discharging protocols are crucial for maximizing battery life. Each cell has a nominal voltage of 3.2 volts, with a maximum charge voltage of 3.65 volts. A Battery Management System (BMS) is highly recommended to prevent overcharging or deep discharging, safeguarding the cells. The project emphasizes safety, noting the batteries' high short-circuit capacity of **200 AMPS** and the critical importance of incorporating an inline fuse between the battery pack and the load. Components like the battery holder, buss bars, and a suitable case are also detailed.

Addresses the common challenge of constructing effective dual-band antennas for VHF/UHF operations, specifically detailing a J-pole design. It covers the theoretical underpinnings, including calculations for quarter-wavelength radiator and stub sections, accounting for velocity factor and design frequency. The resource provides practical construction guidance using readily available materials like TV twin lead and coaxial cable, culminating in an antenna with a total length of approximately 52 inches. Performance metrics are presented, showing a measured SWR of 1.7:1 or better across most of the 2-meter band and less than 2:1 across the 70-cm band. These SWR measurements, referenced to 50-ohm impedance, were taken at the transmitter end of the feed line. The article also touches upon the necessity of a balun for proper impedance matching between the balanced J-pole and unbalanced coaxial feed line, suggesting a split-core cylindrical ferrite for this purpose.

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.

A dual insert microphone design for the Icom IC-7300 transceiver utilizes a **Besson BZ2400 M4 Rocking Armature** insert for frequencies from 500 Hz to 3 kHz, exhibiting a rising response of approximately 11 dB. A generic Electret Condenser insert, powered by the transceiver's microphone line, covers the low-frequency range from 100 Hz to 500 Hz. A Low Pass Filter is incorporated after the Electret insert to prevent frequency overlap, and a pre-set potentiometer (VR1) adjusts the low-frequency response, balancing the output of both inserts. The design emphasizes a "Close Talking" arrangement and addresses audio "colorization" by housing the Besson insert in a thick rubber holder with a foam boot, separate from the circuitry, with the Electret insert also wrapped in a foam boot. Critical importance is placed on using the correct BZ2400 M4 insert with 12 holes in its face plate. The frequency response table for the BZ2400 M4 insert shows 0 dB at 500 Hz, rising to +11 dB at 3000 Hz, while the Electret insert with the Low Pass Filter provides 0 dB at 100 Hz, rolling off to -9 dB at 500 Hz and -50 dB at 3000 Hz. This combination ensures a broad, balanced audio spectrum for SSB operation. The project includes a circuit diagram, a comprehensive parts list detailing components like a 1 Henry iron-cored inductor (L1) and various capacitors, and a board layout within the metal tube. The completed unit provides a tailored audio profile for the IC-7300, enhancing transmit audio quality.

The article by Guy Olinger, K2AV, published in the May/June 2012 National Contest Journal, introduces the Folded Counterpoise (FCP), a compact 516-foot single-wire counterpoise elevated at 8 feet, designed for 160-meter operations on small lots like 100x150-foot backyards. Originating from efforts to revive Top Band for W0UCE on a postage-stamp property, the FCP uses strategic folds to cancel ground fields within 33 feet of center, minimizing losses to 0.13-0.53 dB—outperforming sparse or on-ground radials by up to 15 dB in poor soil—while mimicking opposed radials for efficient feedpoint impedance. Paired with a critical 1:1 or 4:1 isolation transformer (e.g., trifilar on T300-2 toroid) to block common-mode currents on coax feeds, it delivers proven results: K2AV's #8 North America low-power contest score, 7+ dB gains at W4KAZ and K5AF, and over 10,000 global web hits for DIY instructions using bare 12 AWG wire and weatherproof enclosures. Ideal for acreage-challenged hams, the FCP also excels on 80 meters with scaled dimensions, offering a low-loss alternative where full radials are impractical

W1JR-style common mode chokes are versatile tools for antenna experimentation. Three variants were constructed using RK4 ferrite cores and RG303 Teflon coax, differing only in output terminals: banana connectors for dipoles, N-connectors for antennas with existing terminals, and bolts with washers for vertical antennas. Materials included junction boxes, terminals, and small hardware. Assembly involves maximizing windings on the core, securing with ties, and gluing components. Improvements included switching to multi-stranded wire for durability. These chokes provide efficient, customizable solutions for various antenna setups.

Demonstrates the capabilities of DXtreme Monitor Log 14, a specialized software application designed for radio spectrum monitoring and logging. The resource details its core functionality, which includes logging stations across various bands and supporting multiple transmission modes such as AM, CW, FM, LSB, USB, and RTTY. It highlights features like the ability to select country formats for new databases and the **Schedule Checker** tool, which assists users in identifying broadcast stations for monitoring. The software facilitates tracking **Maidenhead grid squares**, particularly useful for VHF and UHF monitoring activities. It also supports QSL management and offers tools for efficient contact logging, catering to both amateur radio operators and shortwave listeners. Specific information includes its version number, Monitor Log 14, and its utility for DXers and other radio enthusiasts in managing their monitoring experiences and logging contacts effectively.

Fifty-one MHz operation, often called the "magic band," benefits significantly from a well-designed antenna, and this resource details the construction of a rigid 6-meter _Moxon antenna_ using common DIY store materials. The author, 4L/G8BAG, shares his experience with the 6m band, highlighting its potential for long-distance contacts, with single-hop sporadic E propagation enabling QSOs up to **2,500 km** and multi-hop contacts reaching **10,000 km**. The project emphasizes cost-effectiveness and durability, utilizing yellow gas pipe with an internal stainless steel lining for the antenna elements. The article provides specific dimensions for the Moxon rectangle, derived from the 12mm internal diameter of the gas pipe's steel core, rather than the outer plastic. It also details the use of white PVC water pipe for insulators and mounting, ensuring a tight fit with the yellow gas pipe. Initial testing with an MFJ antenna analyzer showed an excellent 1:1 SWR across the 50-52 MHz range, even when using 75 Ohm satellite cable as a feeder. The construction process is straightforward, involving cutting and bending the gas pipe, fitting insulators, and connecting the feedline. The author's successful on-air results, including a 1000 km contact with a temporary vertical, underscore the effectiveness of the 6m band and the Moxon design. The resource concludes with a note on exploring heavier gauge gas pipe for future 10m antenna projects.

Improving callsign recognition and copying skills is fundamental for effective amateur radio operation, particularly in high-stress environments like contesting or DXing. The CW4EVER Callsign Training Platform provides a focused environment for operators to hone these abilities. It offers three distinct training modes: a Typing Trainer for visual recognition, an SSB Trainer for voice callsign practice, and a CW Trainer for Morse code proficiency, allowing users to tailor their practice to specific operational needs. Operators can select training durations of 1, 3, 5, or 10 minutes, providing flexibility for quick drills or extended practice sessions. For CW training, the platform allows granular control over parameters such as CW speed, adjustable up to **80 WPM**, pitch in Hz, and weight in percentage, enabling personalized learning curves. The system stores operator preferences locally and includes server-side anti-cheat protection, stricter callsign validation, and automatic score archives, ensuring fair competition and persistent training history. Recent enhancements include separate saved CW preferences per operator and _MY DXCC_ ranking positions. The platform also tracks global statistics, including total attempts worldwide, unique callsigns encountered, and total training hours logged, offering a broad perspective on user engagement and progress. These features collectively support operators in achieving higher accuracy and speed in callsign reception.

Demonstrates a **Progressive Web App** (PWA) approach to amateur radio logging, providing a platform-agnostic solution for hams. The resource details its core functionality, including offline callsign and reference lookups, auto-formatting for data entry, and integration with **POTA spots** and saved re-spots. It highlights support for various logging templates such as General, Contest, POTA, and Field Day, indicating its adaptability for different operating activities. The application emphasizes seamless log synchronization across multiple devices, eliminating the need for manual file transfers. It operates effectively both online and offline, with installation options available for full offline functionality on Windows, Android, iOS, macOS, and Linux, or direct use within any web browser. The documentation further outlines features like rig control and the continuous development of additional templates, positioning Smart Logger as a flexible and efficient tool for managing amateur radio contacts.

This project involved designing a 7-pole Chebychev broadcast band filter to address severe interference issues caused by a new horizontal loop antenna on the KN-Q7A transceiver. The interference overwhelmed the transceiver’s front end, so a custom filter with a 3.5 MHz cutoff was built using silver mica capacitors and type 6 T130 toroidal cores. Encased in a diecast box with SO239 sockets, the filter blocks strong signals from the broadcast band, achieving over 100 dB attenuation. Tested up to 100W, it reduces interference effectively while maintaining low insertion loss across HF bands.

Online impedance calculators grouped by types like Wire inductances, Toroid incuctances, Plane, PAD, Strap inductances, but even Core and Coax Inductances. Air core inductances and mutual inductance groups are also availbale. All these calculators let you input specific paramenters based on the inductor selected and will calculate specific incutance and related dimensions.

For phased C-Poles, matching choke baluns are essential to maintain intended phasing, beam pattern, and gain. The author uses a low-loss, ferrite-core balun design with 19 turns of RG-174/U coax for optimal performance.

DF6QV's 4-Square antenna analysis begins with a two-element array simulation, demonstrating azimuth and elevation plots for various phase differences, including a 75-135 degree range. The document then delves into the core components of a 4-Square system, such as radiators, couplers, phasing lines, and ground systems, referencing W1HKK's 1965 QST article on an 80m phased array. It explores the influence of ground conditions and element spacing on antenna performance, presenting EZNEC analysis for an 80m 4-Square with an elevated radial, showing how gain and beamwidth vary with spacing. Various 90-degree couplers, including the 3 dB hybrid coupler and the Reed Fisher coupler, are analyzed using LTSpice, detailing power splitting, phasing, and bandwidth characteristics. The resource quantifies power, voltage, current, and losses within a 4-Square system, addressing relays, capacitors, inductors, radiator radial systems, and cable losses. System impedance, bandwidth, SWR, isolation, and mutual coupling are discussed with practical construction aspects covering common mode chokes, phasing boxes, and remote control systems. Field test observations for 40m 4-Square antennas are included, with specific examples from DXpedition operations like 5A7A and VP6DX, providing real-world context to the theoretical and simulated results.

The influence of temperature changes in Common Mode Chokes. To get an indication of the impedance behavior when the core temperature changes, the author tested a CMC by heating it with a hairdryer, and measuring its temperature with an infrared thermometer. When the CMC temperature rises from 30C to 90C, the frequency of maximal impedance shifts down from ca.10 MHz to ca.7.2 MHz, or by a factor 1.4.

This article investigates SSB signal quality during the CQ WW 2015 SSB contest. It highlights the importance of adhering to the ideal SSB signal profile, the impacts of intermodulation distortion, and the consequences of poor-quality signals. The analysis underscores the need for well-tuned equipment to ensure cleaner, more efficient signals and, consequently, a more enjoyable and spacious experience for contest participants and amateur radio operators.

Demonstrates the construction of an active loop converter specifically designed for the Low Frequency (LF) bands, addressing common localized noise interference in LF reception. The design integrates a sharply tuned circuit and a tuned loop antenna, utilizing the loop as the sole tuned inductive element. By applying positive feedback, the converter significantly increases the loop's effective Q, achieving factors between 1000 and 2000, which sharpens tuning and reduces noise. The circuit employs an _NE602_ mixer stage, feeding its output to an HF receiver, with a crystal-locked local oscillator at 4 MHz. A 20-turn, 0.8-meter square loop antenna with 500 uH inductance is detailed, connected via 2 meters of figure 8 flex cable. The converter offers three selectable frequency bands: 195-490 kHz, 150-220 kHz (including the New Zealand amateur band), and 128-160 kHz (covering the European amateur band). Performance measurements indicate an effective 3dB bandwidth of approximately 100 to 200 hertz at 200 kHz. The article provides insights into component selection, including an _LF353_ op-amp and a trifilar wound transformer on a ferrite core. Sensitivity figures are presented, showing 7.5 uV of converted output per 1 uV/meter signal strength into a 50-ohm load, or 37.5 uV into an _FRG7_ receiver, highlighting its capability to extract weak signals from noise.

Details the construction and performance of a phase-controlled receiving array, specifically a **MicroSWA** variant, optimized for QRP low band fox hunting on 40M and 80M. The resource documents the author's iterative design process, addressing significant regional noise challenges encountered during 0100-0230 UTC fox hunt periods. Initial experiments involved a director wire on a 40M vertical, yielding limited improvement, prompting a shift towards advanced null-steering techniques. The project leverages concepts from Victor Misek’s "The Beverage Antenna Handbook" and Dallas Lankford’s extensive work on phased receiving antennas for urban lots. A key modification involved integrating a new passive phase control box and a push-pull **Norton common base preamp** using 2N5109 transistors, designed for high third-order intercept performance to maintain weak signal integrity amidst strong adjacent signals. The system incorporates Faraday-shielded transformers with RG174 primaries on -75 ferrite cores, housed in ABS plastic pipe. Performance tests confirmed the MicroSWA's ability to produce deep, steerable nulls, achieving approximately 30 dB noise reduction on 160M, 80M, and 40M. This enabled detection of QRP signals undetectable on conventional transmit antennas. The final unit includes front panel controls, a 10-11 dB preamp, and a robust power conditioner, demonstrating effective noise mitigation for challenging low band QRP operations.

SDR Television v1.0 operates as a DVB-S2 / AAC / H264 / H265 program, specifically engineered for QO-100 satellite Digital Amateur Television (DATV) operations. It provides a full-duplex solution on modern x86 computers running Windows 10 or 11 (64-bit, 8+ cores, AVX2 support recommended), leveraging DLLs from _SDR Console_ for control of devices like _Pluto_ and _LibreSDR.TV_. The software requires installation of the SDR Radio kit for wideband mode support. Initial development focused on a proof-of-concept for QO-100, with future enhancements planned to include H266 / AV1 / Opus codecs and an improved cross-band user interface. The current stable release functions reliably for QO-100 DATV. Users must install the SDR Radio kit, followed by the SDR Television kit, into the same directory. Support inquiries are handled via the SDR-Radio.com mailing list, ensuring direct assistance for operational questions.

The article "Icom IC7300 RTC Fix" details the meticulous repair of an Icom IC-7300's faulty real-time clock (RTC). The author and a friend, Nacho, discovered the RTC was gaining an unacceptable 11 seconds per day. Investigations revealed the Seiko Epson RX8803LC RTC was far outside its specified stability. Despite replacing the RTC and a burned pullup resistor, the transceiver still malfunctioned, leading to the replacement of the processor. Post-repair, the clock's accuracy improved significantly, now gaining only 1.4 seconds per month. This narrative underscores the complexities of electronic repairs and the satisfaction of resolving intricate issues.

Online Coil Inductance Calculator. To calculate the inductance of a single-layer, air-core coil, just select the measurement units, enter the number of turns, the coil diameter and the coil length.

Operating amateur radio satellites presents unique challenges, particularly concerning antenna design and signal propagation. Juan Antonio Fernández Montaña, EA4CYQ, recounts his three-year journey into satellite communication, starting with initial guidance from EB4DKA. His early experiments involved a portable 1/4 wave VHF antenna with four 1/4 wave ground planes, designed for hand-held use to adjust polarity. This setup, paired with an FT-3000M transceiver, allowed full-duplex operation on **VHF** transmit and **UHF** receive, proving effective for early contacts on satellites like AO27, UO14, and SO35. EA4CYQ's experience highlights the critical role of coaxial cable loss and antenna polarization. After encountering significant signal degradation with longer RG213 runs, he experimented with a 1/2 inch commercial cable, noting improved reception but persistent fading due to varying satellite polarities. This led to the construction of an **Eggbeater II** antenna, an omnidirectional UHF design offering horizontal polarization at the horizon and circular right polarization at higher elevation angles. Subsequent modifications resulted in the directional **TPM2** antenna, which provided sufficient gain for LEO satellites with a wide 30-degree lobe, enabling consistent contacts from his home station. The article concludes with practical insights on the performance of the Eggbeater II for both UHF and VHF, and the TPM2 for UHF, emphasizing their utility for portable and fixed operations. EA4CYQ's journey underscores the iterative process of antenna development and the importance of adapting designs to overcome real-world propagation challenges in satellite communications.

Logbook, contest score, calendar, EQSL, DX Expeditions streams and much more! HamPass is a complete tool for ham.

This FAQ covers building and buying transformers for loop-on-ground and Beverage antennas. Building one uses ferrite cores and thin wire. Buying is an option, with the DX Engineering BFS-1 being recommended. These transformers isolate the antenna from the cable to prevent unwanted signal pickup.

Tracing the foundational work of Guglielmo Marconi, this article details his early laboratory experiments in 1895, where he successfully transmitted wireless signals over 1.5 miles. It highlights his 1896 patent for a wireless telegraphy system in England and subsequent demonstrations, including signal transmissions up to 6.4 km (4 miles) on Salisbury Plain and nearly 14.5 km (9 miles) across the Bristol Channel. Marconi's work built upon the mathematical theories of _James Clerk Maxwell_ and the experimental results of _Heinrich Hertz_, proving the practical feasibility of radio communication. The resource further chronicles the formation of The Wireless Telegraph & Signal Company Limited in 1897 and Marconi's relentless efforts to popularize radiotelegraphy. A significant milestone was the 1901 transatlantic reception of the Morse code letter "S" from Poldhu, Cornwall, at St. John's, Newfoundland, using a kite-supported wire antenna, defying contemporary mathematical predictions about Earth's curvature limiting range. This achievement underscored the global potential of radio. The article also touches upon Marconi's later discoveries, such as the "daytime effect" concerning atmospheric reflection of radio waves, and his 1902 patent for a magnetic detector, which became a standard wireless receiver. His contributions earned him a Nobel Prize in 1909.

This document provides a comprehensive guide on renewing an US amateur radio license through the Federal Communications Commission (FCC) using the new COmmission REgistration System (CORES). Published on QST October 23, it outlines the necessary steps for creating a CORES account, associating it with a Federal Registration Number (FRN), and completing the renewal application. Key points include the requirement of a $35 fee for the renewal process, which must be paid online after the application is submitted. The guide emphasizes the importance of logging into the FCC License Manager system during the renewal window and provides instructions on how to navigate the renewal process, including obtaining confirmation and access to the renewed license. Additionally, it offers contact information for FCC support and links to further resources for assistance.

HamStream, a versatile ham radio control software, integrates real-time DX cluster data directly into the operator's workflow, eliminating the need for constant alt-tabbing. As an Extra Class operator, I appreciate how it instantly displays callsign, country, distance, bearing, and QRZ profile data for spotted stations, mirroring the efficiency of a well-organized shack. The software acts as a comprehensive radio controller, reading frequency, mode, and S-meter in real time from connected rigs, supporting CAT via serial, CI-V, _HAMLIB_, and direct connections to _FlexRadio SmartSDR_ and Apache Labs ANAN (via Thetis). Key features include instant QRZ lookups, distance and bearing calculations with a live great-circle minimap, and favorite alerts for specific callsigns. The one-click logging functionality is particularly useful, populating callsign, frequency, and mode into _N1MM+_, Log4OM, DXKeeper, Logger32, StationMaster Pro, and Ham Radio Deluxe via UDP, streamlining contest and casual logging alike. Its smart radio auto-detection for port, baud rate, and model simplifies setup, a welcome relief from manual configuration. Beyond core operating, HamStream also displays 'Also on this frequency' information and can tune the radio to spotted frequencies, enhancing situational awareness. For those who stream their operations, it offers an OBS overlay with live viewer counts and chat integration, making it a compelling tool for modern amateur radio engagement.

Constructing a 4:1 Guanella current balun involves cross-connecting two 1:1 current baluns. At the low-impedance end, transmission lines from each balun are connected in parallel, while at the high-impedance end, they are connected in series. This configuration allows the device to achieve a 1:4 impedance ratio, effectively transforming a 200-ohm load to 50 ohms. The balun described utilizes **FT240-43 toroids** wound with 2.5mm2 twisted pair cable for 8 turns, intended for use with a 20m **Deltaloop antenna**. Measurements performed with a 200-ohm resistor demonstrate satisfactory VSWR and impedance characteristics across the HF bands. The article compares the performance of 2.5mm2 cable versus 1mm enameled wire, recommending the former for superior efficiency. Emphasis is placed on maintaining short core-terminal connections to optimize performance. Additional considerations include the option of integrating a separate Common Mode Choke (CMC) for enhanced common mode current suppression, especially if the balun's inherent suppression is not prioritized.

AA9PW offers free practice exams for all three US license classes plus international licenses like Canadian and Australian. The site generates random tests from the current question pools, simulating the actual exam experience. You can choose between online exams or printable PDF versions for offline study. The site maintains a simple, no-frills interface that loads quickly even on slow connections. Practice tests provide immediate feedback with score reports highlighting areas needing improvement.

A common mode choke/balun, essential for mitigating common mode current on antenna feedlines, is detailed in this construction and measurement guide. It utilizes eight Fair-Rite #2643167851 Mix 43 ferrites housed within a Hammond 1598JSGYPBK plastic case, with RG-8X coax cable forming the windings. The document references design principles from Ian White, GM3SEK's article on cost-effective ferrite chokes. Specific construction details include the layout of three coils to minimize inter-coil coupling and methods for securing the ferrites with foam tape. The resource presents comprehensive measured data, including isolation impedance (magnitude, real, and imaginary components), Q factor, inductance, and phase angle across various frequencies. It also covers the choke/balun's coax frequency response and return loss characteristics. Techniques for measuring choking impedance are thoroughly explained, focusing on S21 transmission measurements with a Vector Network Analyzer (VNA) and testing ferrite beads in both S11 and S21 modes. The guide describes a practical setup using an aluminum sheet or baking foil for measurements and outlines the calculation of series impedance from attenuation in a 50-ohm system. Additionally, it details a method for determining the balun's equivalent L and C around resonance by adding a parallel capacitor.

The 4m Slim Jim antenna project provides a construction guide for a low-cost, high-performance aerial designed specifically for the 70 MHz FM band. This design achieves a 1:1 SWR across the 4m FM band with straightforward adjustment of the feed point, utilizing RG-58 coax. Its low angle of radiation contributes to effective signal propagation. Construction involves using plastic knitting needles as spreaders and a telescopic fishing pole for support, with components secured using two-part epoxy. Annealed bare single-core copper wire forms the radiating element. The setup process includes raising the antenna at least 3 meters above ground for tuning, adjusting the RG-58 feed point for optimal SWR, and then soldering connections. Waterproofing is achieved with yacht varnish. The design emphasizes low wind resistance for durability, making it suitable for exposed outdoor installations. A PDF construction diagram is available to supplement the written instructions.

The aprs.fi Android application offers immediate, real-time access to APRS position information, weather reports, and telemetry graphs, allowing users to zoom and browse stations globally without delay. It includes features like callsign and address search with history, multi-station tracking, and map filtering for elements such as weather stations and AIS targets. The app also supports KML and GeoJSON overlay files for enhanced map visualization. Users can beacon their position directly to aprs.fi or connect wirelessly to a Bluetooth, BLE, WiFi, or USB-attached TNC for receiving and transmitting position beacons without an internet connection. The application runs on the robust and fast aprs.fi database, providing _Dark Mode_ support for improved ergonomics in low-light conditions and high-resolution graphics for modern displays, including the full APRS symbol set. While the core application is a one-time purchase, some advanced functionalities, such as APRS text messaging, a high-performance software DSP modem, and _APRS-IS_ beaconing with up to **10 callsign profiles**, require an additional "Extra Features" subscription. This subscription also unlocks RX iGate functionality and extended time ranges for map and graph views, expanding its utility for serious APRS operators.

VE2AZX's 2013 Radio Talk presentation details the technical aspects of baluns, including reasons for their use, various types, and methods for performance verification using an SWR analyzer. The document specifically examines 1:1 voltage baluns and 4:1 voltage baluns, outlining their winding configurations and typical impedance transformations. It presents empirical SWR measurements for W2AU 1:1 baluns and Unadilla 4:1 baluns, tested with both 50-ohm and 200-ohm resistive loads across the HF spectrum. The presentation further explores the measurement of ferrite impedance and their application in mitigating common-mode currents on feeders and household conductors. Key concepts addressed include balanced-to-unbalanced transformation, ensuring feeder independence from the antenna, and reducing unwanted feeder radiation. The content emphasizes practical testing procedures to ensure optimal antenna system performance and minimize RF interference. Discussions also cover open-circuit tests with SWR analyzers and VNAs to assess winding inductance, distributed capacitance, and insulation quality. The presentation differentiates between voltage and current baluns, explaining how current baluns, particularly those utilizing ferrite cores, reduce outer shield currents without affecting internal coaxial cable currents, thereby preserving the antenna's intended radiation pattern.

The resource provides a technical installation guide for _MeshCom 4.0_, an amateur radio mesh networking project utilizing LoRa hardware modules. It systematically covers the setup process for several supported devices, including the RAK Wireless LoRa WisBlock Core RAK4631, T-Beam T22 V1.1, T-Lora T3 V1.6.1, HELTEC WiFi ESP32 LoRa 32 (V2 and V3), HELTEC E290, ESP32 / E22 modules, and the T-deck from Lilygo. The guide specifies support for the **EU433** frequency band, ensuring amateur radio compatibility, and details the use of an online flash tool for ESP32 modules and an embedded drive for RAK modules. It further describes accessing the MeshCom 4.0 Dashboard and Map functionalities, crucial for network visualization and management. Firmware configuration for ESP32 modules is meticulously outlined, covering essential parameters such as setting callsigns, country codes, and gateway parameters via a serial console like PuTTY. Commands for activating gateway mode, setting internet IP addresses, and configuring WLAN SSID and password for modules with WLAN capability are provided, enabling modules to function as either clients or gateways within the MeshCom network.

This resource provides a procedural guide for renewing an amateur radio license online through the FCC's COmmission REgistration System (CORES) and Universal Licensing System (ULS). It details the steps for creating a new FCC CORES username account, linking an FCC Registration Number (FRN) to the account, and managing FRN passwords. The document outlines the process for submitting a renewal application via the FCC ULS License Manager system, including payment of the **$35** renewal fee. Instructions cover license renewal eligibility within **90 days** before expiration and during the 2-year grace period post-expiration. The guide specifies the use of the FCC CORES web page at `https://apps.fcc.gov/cores/userLogin.do` for account setup and the FCC ULS License Manager system at `https://wireless2.fcc.gov/UlsEntry/licManager/login.jsp` for application submission. The process concludes with receiving an email from the FCC containing a link to the official license, valid for 30 days.

The Meshtastic project leverages _LoRa_ radio protocol to establish a long-range, off-grid communication platform, functioning as a decentralized mesh network. It facilitates sending and receiving text messages using inexpensive LoRa radios, eliminating reliance on traditional infrastructure or a smartphone for core mesh communication. Key features include encrypted communication, extended battery life, and optional GPS-based location services, with radios designed to rebroadcast messages to ensure delivery across the mesh. This system has demonstrated a record range of **331km** and is entirely community-driven and open source, with its codebase hosted on GitHub. Unlike conventional amateur radio, Meshtastic operates on LoRa frequencies generally accessible without specific licenses. Each Meshtastic radio can pair with one phone for message exchange, and support is provided by volunteers.

The State QSO Party Challenge is an annual program recognizing amateur radio operators' participation in U.S. State and Canadian Province QSO parties. To qualify for the SQP Challenge, participants must make at least two QSOs in a minimum of two SQP Approved QP contests and submit their scores to 3830Scores.com. The site details the SQP Mobile/Portable Challenge, an overlay competition encouraging mobile/portable operations, with scoring identical to the main SQP Challenge: (Number of QPs entered) x (Number of QSOs) = Score. Eligibility for the Mobile/Portable Challenge requires prior qualification for the SQP Challenge. The website also mentions a State QSO Party Club Challenge and provides contact information for questions. The 2026 SQP Challenge will be dedicated to Stan Zawrotny, K4SBZ, a key team member instrumental in the program's development. Participants are recognized for reaching five levels of achievement: Bronze, Silver, Gold, Platinum, and Diamond. Scores are calculated by totaling reported contacts and multiplying by the number of SQPs entered year-to-date, encouraging more entries and longer operating times. The Worked All QSO Parties (WAQP) program, sponsored by Icom America, offers certificates for participating in at least 50% of approved contests, with a goal of participating in all. WAQP requires submitting a log with at least two valid contacts to the contest manager, in addition to the 3830scores.com submission.