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The N1HFX thermal cooling fan controller project details a practical circuit designed to manage cooling fan operation based on temperature, a common requirement for high-power amateur radio equipment. This build utilizes a **LM34** temperature sensor, providing a linear voltage output directly proportional to Fahrenheit degrees, simplifying the control logic. The circuit's core functionality involves a comparator that activates the fan when a preset temperature threshold is exceeded, ensuring efficient cooling and reducing unnecessary fan noise. This controller is particularly useful for amplifiers, power supplies, or transceivers that generate significant heat during operation. The design incorporates a _TIP120 Darlington transistor_ to drive the fan, capable of handling up to 5 amps, making it suitable for a range of fan sizes and current requirements. Field results indicate stable temperature regulation, preventing thermal runaway in enclosed environments. Construction involves readily available components, making it an accessible project for hams looking to optimize their station's thermal management.

Operating Morse code (CW) relies on a diverse array of **telegraph keys**, each with unique characteristics and historical significance. This resource presents a personal collection of such keys, offering visual documentation and details on various models. It features early Marconi keys from the 1900s, including specific models like the Marconi Air Ministry Key and Marconi Coastal Station Keys, alongside **Vibroplex** bugs and JRC keys. The collection also highlights rare items such as the Brown Brothers Magnetic Twin Paddle Key, the Eddystone Bug Key, and Swedish SRA Ericsson Keys. Enthusiasts can view examples of GPO Double Current & Single Current Keys, Navy NATO Keys, and specialized aircraft and maritime keys. The site includes information on historical training devices like the OMNIGRAPH and a Morse Inker from 1900, providing context for the evolution of telegraphy equipment. Additionally, the resource showcases unique items like the B2 Spy Set SOE Agents Key and a WW2 Junker U-BOAT KEY, illustrating the varied applications of Morse keys throughout history. The author, G0RDO, also shares details on a home-made paddle key and invites inquiries for acquiring interesting Morse keys.

Demonstrates the construction of a high-power 6-meter (50 MHz) amplifier, specifically designed for demanding modes like EME, TEP, and multiskip Es. It details the use of a _GU-43B_ tetrode in a grounded-cathode configuration, emphasizing the need for stabilized grid voltage and input capacitance compensation. The resource provides a comprehensive schematic, power supply design, and practical considerations for component sourcing, particularly for high-voltage and high-current sections. The builder achieved an output power of **1250 watts** with an anode current of 0.65 amperes and 3200 volts anode voltage. The article also covers the physical construction within a modified P6-31 enclosure, outlining the internal layout for RF and power supply sections, and includes photos of the completed unit. It highlights critical safety precautions for working with high voltages and reactive currents up to **20 Amperes** in the P-network.

The original SurplusEQ.com domain, once a hub for amateur radio operators and electronics enthusiasts seeking test equipment, meters, and various high-tech components, has been repurposed. Historically, such platforms facilitated the acquisition of essential gear for shack setups, antenna analysis, and general electronics work, often providing cost-effective alternatives to new retail purchases. The site's previous focus on "test equipment, meters, testers" directly supported the technical aspects of the hobby, from RF measurements to circuit diagnostics. Currently, the domain points to a gambling platform named "SEMUTWIN," offering online slot games, live casino options, and other digital wagering activities. This shift represents a complete departure from its former identity as a resource for surplus electronics and amateur radio-related equipment. The content now features game titles like "Sweet Bonanza Super Scatter" and "Gates of Olympus Super Scatter," alongside promotional offers for online gaming.

Constructing a basic multimeter involves integrating a 0-1mA meter movement with various shunts and multipliers, selected via a switch, to create a versatile instrument capable of measuring DC volts, current, and resistance. The design outlines two main units: a primary unit handling six DC current ranges up to 1 amp and eight DC voltage ranges up to 1000 volts, alongside an internal battery for an ohms range up to 200,000 ohms. This approach allows for a practical, hands-on understanding of meter operation. An add-on unit further extends the multimeter's capabilities, incorporating a meter rectifier and switched series resistors to provide four AC voltage ranges up to 100 volts. Additional shunt and series resistors, designated Ra and Rb, are included to expand the instrument's range to 10A and 5kV, demonstrating how modular design can enhance functionality. When this add-on is in use, the main instrument is set to measure 1mA FSD, connecting via specific lugs. Component selection emphasizes precision, with 1% tolerance high stability resistors for series elements and Eureka resistance wire for shunts. The design specifies values calculated for a meter with 60 ohms internal resistance, noting that these would require modification for different meter characteristics. Experimental adjustment of shunt values is recommended to ensure accurate readings against a calibrated reference meter, reinforcing practical calibration techniques.

The DXCC World Map web application is a modern and interactive mapping tool designed for shortwave radio enthusiasts. It showcases a high-quality world map along with the Sun's position, sunrise and sunset times, the terminator, coordinates, QTH locator, azimuth, azimuth map, current DXCC list, Aurora, and WWV Geophysical Alert Messages. Additionally, it provides the SFI, X-Ray, Kp, and Ap indices.

Details the Highline Amateur Radio Club (HARC), an organization dedicated to public service through Amateur Radio and community engagement for radio enthusiasts. The club conducts a monthly general meeting on the 4th Saturday at 10 AM at Burien Fire Station 28. HARC also hosts a weekly net on Tuesdays at 7:30 PM, operating on **146.660 MHz** with a -600 kHz offset and a 103.5 Hz **CTCSS tone**. Additionally, members gather for a weekly breakfast on Fridays at 9:30 AM at Tuscany at Des Moines Creek. The resource provides current weather conditions for Burien, WA, displaying temperature, wind chill, and a three-day forecast from the National Weather Service Seattle/Tacoma Office. It also links to the latest ARRL Newsletter, noting a system breach in May 2024 affecting archived links. The club's activities include regular meetings, on-air nets, and social gatherings, supporting local amateur radio operations and community involvement.

The resource, "Conventional Use of Transmission Line," meticulously details the operational principles of transmission lines, emphasizing the Transverse Electromagnetic (TEM) mode of energy transfer. It clarifies that for a line to function purely as a transmission line, all currents must be confined internally, with external fields ideally zero. The discussion differentiates between balanced and unbalanced lines, asserting that while both require equal and opposite currents within the conductors, the key distinction lies in the voltage relationship of each conductor to the surrounding environment. It highlights that a good antenna pattern does not inherently confirm proper feeder balance, and that common-mode currents can lead to RF in the shack and increased noise levels, even without pattern distortion. The article further explains that a transmission line can become a radiating conductor if energy is applied in a non-TEM mode, leading to common-mode issues. It cites classic texts like Jordan and Balmain's "_Electromagnetic Waves and Radiating Systems_" and Kraus's "_Antennas_" to support its definitions of TEM mode operation. The content also explores non-transmission line applications of parallel or concentric conductors, such as _coaxial dipoles_ and _folded dipoles_, which intentionally operate in non-TEM modes for antenna functionality. The author, _W8JI_, stresses that simply measuring equal currents is insufficient to confirm a balanced feeder; phase and voltage balance to ground are equally critical.

One common semiconductor material, silicon, is far more widely used in electronics than germanium, partly because it can operate at much higher temperatures. Semiconductors are crystalline materials with electrical resistivity values between conductors and insulators, whose conductivity can be altered through _doping_ with impurities like arsenic or phosphorous to create N-type (excess electrons) or P-type (electron vacancies) materials. Semiconductor devices, such as diodes, transistors, and integrated circuits, leverage these properties to control electron flow in circuits. A diode, a two-terminal device with an anode and cathode, primarily permits current flow in one direction, making it useful as a rectifier to convert AC to DC. Specialized diodes include Zener diodes for voltage regulation and Light-Emitting Diodes (LEDs) that produce light when current passes through them. Logic circuits, fundamental to digital electronics, have binary inputs and outputs, performing functions like AND, OR, and NOT gates, and can be constructed from various binary devices including solid-state diodes and transistors. A transistor is an active semiconductor device with at least three terminals (base, emitter, collector), capable of amplifying current. Integrated circuits (ICs), often called chips, are electronic circuits built on a semiconductor substrate, typically silicon. ICs are classified by transistor type (bipolar or MOS) and integration scale: Small-Scale Integration (SSI) with fewer than 10 transistors, Medium-Scale Integration (10-100), Large-Scale Integration (LSI) with 100-1,000, and Very-Large-Scale Integration (VLSI) with more than **1,000** transistors. ICs can be analog, digital, or hybrid, offering virtually limitless functions.

Lightning Arrestors, High current filters manufacturer

Make them simple then Make them work. The LAZY H antenna is a general type of antenna that is in the curtain array family. By placing two 1 wavelength dipoles in a plane that is at right angles to the direction of maximum radiation and keeping the proper in-phase current condition to each element, you can achieve a high gain bi-directional antenna.

Operating in a Single Operator Two Radios (SO2R) setup, especially with beverage antennas, often exposes the receiving radio's front-end to significant RF energy from the transmitting radio. This resource details a practical, homebrew receiver protection circuit designed to mitigate this risk. The core of the design involves a non-inductive 2W 22 Ohm carbon composition resistor in series with the RX antenna line, followed by two stacks of four fast-switching diodes (e.g., _1N914_) configured in opposite polarizations. This arrangement effectively clamps the incoming voltage to approximately 2.8 V peak-to-peak, safeguarding sensitive receiver input components. The series resistor plays a crucial role by absorbing excess power, preventing the diodes from exceeding their current ratings and potentially failing open, which would leave the receiver unprotected. The author, _N4KG_, measured up to 50 watts of coupled power between 80M slopers on the same tower, highlighting the necessity of such protection. The design is presented as a cost-effective solution to prevent damage to receiver input transformers, with the author noting successful protection of a receiver even after a resistor showed signs of overheating. This simple circuit can be integrated via a transverter plug, offering a robust defense against high RF input.

Covers the WB2JKJ Educom HF Net, which operates on 7.238 MHz and 21.395 MHz. This resource highlights the activities of The Radio Club of Junior High School 22 NYC, Inc., a non-profit organization established in 1980. The club's mission, "Education Thru Communication" (EDUCOM), focuses on integrating amateur radio into schools across the nation as a teaching theme. WB2JKJ, Joe Fairclough, founded and presides over this club, which is recognized as NYC's largest ham radio club. The site also provides access to the "APPLE SLICE NewsletterCurrent Edition" and information on how to support the organization. It includes a scrapbook section and contact details for further engagement. The content was last updated on May 5, 2023, reflecting recent activity.

Accessing current operational statistics for a DXpedition is crucial for DXers planning their next contact. This Club Log page provides a detailed, real-time overview of the 3Y0J Bouvet Island operation, a highly sought-after DXCC entity. It presents a dynamic dashboard showing total QSOs, unique calls worked, and duplicate contacts, all updated as logs are uploaded from the remote location. Users can observe the expedition's progress and strategize their operating times. The interface features interactive charts and graphs, allowing operators to analyze the _3Y0J_ log data by band and mode, including CW, FT8, and SSB. A breakdown of QSOs by continent provides insight into propagation patterns and where the expedition has focused its efforts. The page also includes a map for checking real-time propagation conditions to Bouvet Island, which is invaluable for optimizing contact attempts. Further details include the first and last QSO times, total operating days, and the impact on users' DXCC totals, such as new bands, modes, or DXCC entities worked. This resource is a vital tool for the DX community, offering transparency and actionable intelligence for chasing one of the rarest entities on the air.

Over 15 years of continuous operation, Ham365 provides a web-based logging solution for Amateur Radio Operators, allowing them to maintain and share their QSO records online. Originally launched as the online logbook component of Ham Radio Deluxe, it has since evolved into an independent platform, now integrating with numerous other logging applications. The platform shares its database with HRDLOG.net, ensuring that operations performed on one site are reflected on the other, maintaining data consistency for users. Key features include an overview of the latest hour's activity, a display of the most recent QSOs, and a map visualizing recent contacts. It also highlights "Most Wanted" entities and ongoing DXpeditions, providing a dynamic view of current amateur radio activity. The logbook supports various operating modes, including SSB, RTTY, PSK31, and FT8, and handles ADIF data for interoperability. Users can manage their logbooks, track DX activity, and utilize features like OQRS (Online QSL Request System) through its integrated functionalities. The system is designed to be accessible to a wide range of operators, from casual ragchewers to avid DXers and contesters.

The Peilgruppe Neandertal, featured on Peilsport.de, actively promotes _Amateur Radio Direction Finding_ (ARDF), also known as fox hunting. This German group combines radio technology with outdoor sport, participating in regional and national ARDF events. Members access current ARDF schedules, competition results, and downloadable certificates directly from the site. The content highlights the adventurous spirit of ARDF, emphasizing the blend of technical skill and nature exploration. DL7ET and DR9P are noted callsigns associated with the group, indicating active participation from experienced operators. The site also covers related activities like Foxoring, a variation of ARDF that integrates orienteering with radio direction finding. This resource serves as a central hub for the Neandertal group's activities, documenting their involvement in a sport that challenges both physical endurance and radio proficiency.

The HF Beacon Tracker is an advanced interactive tool designed for DXers and ham radio opoerators in general to monitor active beacons operating below 14 MHz. Built upon a high-fidelity 3D Earth globe, the application provides a spatial perspective on signal paths by integrating real-time environmental data with a comprehensive beacon database curated by Mirek OK1DUB. Beacons are plotted using precise Maidenhead locators and feature a real-time day/night terminator overlay to help operators identify Gray Line propagation opportunities. With a single click, users can calculate the exact distance from their own QTH to any beacon, visualized via an animated Great-Circle Path arc on the globe surface. To enhance its diagnostic capabilities, the tool seamlessly integrates with PSK Reporter, allowing users to right-click CW beacons to instantly fetch current reception reports and signal strength data. The interface is fully optimized with a mobile-responsive design, smooth globe rotation, and togglable Dark/Light themes suitable for any shack environment. Whether you are performing antenna gain tests, conducting ionospheric research, or simply hunting for band openings, the HF Beacon Tracker transforms raw database information into an intuitive, visual diagnostic suite. It serves as an essential asset for any operator looking to master HF band conditions.

This tutorial provides detailed instructions for constructing a DIY magnetic loop antenna, ideal for amateur radio operators seeking efficient short wave communication. The design features a remote tuning system utilizing an Arduino and RC servo, making it suitable for indoor use where larger antennas cannot be installed. Magnetic loop antennas are compact and can operate effectively in confined spaces, but they do require careful handling due to the high voltages and currents they generate during operation. Users should possess the necessary technical skills to implement this project safely. The tutorial includes a comprehensive overview of the antenna's theory, specifications, and mechanical design. It outlines the components needed, including a Soviet-made variable capacitor and a digital RC servo for tuning. Safety precautions are emphasized, as the antenna can produce several kilovolts of voltage and high currents. The project is not certified for safety, and users are advised to proceed at their own risk. The tutorial also provides diagrams and explanations of the antenna's operation, making it a valuable resource for both beginners and experienced operators looking to enhance their setup.

Eaton provides a comprehensive suite of power quality solutions, ranging from compact single-phase isolation units to high-capacity megawatt sag correction systems. The resource details Eaton's engineering expertise in addressing diverse power quality challenges, emphasizing the distinction between DC resistance and apparent AC resistance under heavy current loads within AC power distribution systems. Specific **Marine-Grade surge protective solutions (SPD)** are highlighted, designed to safeguard critical safety and navigation equipment on vessels and rigs against unpredictable power transients in harsh environmental conditions. The company's commitment extends to providing appropriate solutions for critical power systems, ensuring quality installation. The site also features customer testimonials from entities like Federal Express, Kutztown University, J. C. Penney, and Fairchild Aircraft, attesting to the effectiveness of products such as 'The Protector' in preventing equipment damage and downtime.

This page provides information on designing a lightweight Moxon antenna for the upper HF bands and VHF. The Moxon antenna is a compact version of a 2-element Yagi with folded elements, offering good forward gain and a high front-to-back ratio. It is designed for a single band with a feed-point impedance close to 50 ohms. Hams can orient the antenna horizontally or vertically, with polarization following the configuration, affecting radiation patterns. The page allows users to generate radiation pattern plots, VSWR charts, antenna currents diagrams, and Smith charts for their antennas on different ground types, helping them understand antenna performance in the field.

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_.

The Ukrainian Contest Club (UCC) website details contest activities, including a March 2026 contest calendar compiled by _UW3WF_ that excludes specific "exotic" tests, mini-tests, sprints, VHF competitions, and events organized by Russian entities. It lists major contests such as the ARRL International DX Contest, Stew Perry Topband Contest, and CQ WPX SSB Contest, providing dates, times, modes, bands (e.g., **10-160m**), organizers, log submission methods, and deadlines. The resource also highlights Ukrainian participation in various international contests, noting specific callsigns that represented the UCC, and acknowledges new Ukrainian records, such as UW5Y's new record in the ARRL DX CW Contest. The site presents contest results and rankings, including the top 20 Ukrainian contesters in the World Amateur Radio Contesting Association (WARCA) rating for 2019-2024, with _UW1M_ ranked #18 globally and #1 in Ukraine with **26,490.32** points. It also details the club's 12th place finish among 155 clubs worldwide in the CQ WPX Contest 2024 (CW + SSB). The resource includes information on WRTC 2026 participants from the club and lists members excluded due to collaboration with adversarial entities, reflecting the current geopolitical context.

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.

DIY project of a QRP Balun. Using a high permeability ferrite rod and an old B&W dipole center insulator, he constructs a choke type balun for QRP use. The balun aims to create as much inductance as possible at HF, offering a high impedance to common mode currents

This page provides updated data and statistics about United States amateur radio operators, including historical totals, demographics, and geographic distributions. It also explains the Amateur Radio Service, highlighting its role in promoting wireless communication and technological advancements. The page is a valuable resource for hams interested in understanding the current landscape of amateur radio in the United States.

OpenRTX is a free and open source firmware for digital ham radios. The firmware is designed with a top-down approach with the objectives of modularity, flexibility and high performance. Currently, it targets some Tytera Radioddity Baofeng digital radios

In this article, the current consumption for a selection of popular HF transceiver was examined to determine, via an on the field comparison, whether they were right for portable operation. The radios evaluated include the Yaesu FT-857D, Kenwood TS-590SG, Icom IC-7100, and Kenwood TS-480SAT. The measurements were taken beginning frok 5W in 5W increments up to 100W. The results showed that the Kenwood TS-590SG had the highest current use while the Yaesu FT-857D had the lowest. The current consumption of all radios increased as the power output increased.

A cost-effective alternative to the Optibeam OB10-3W, a high-performance but expensive tri-band Yagi antenna for the 20, 17, and 15-meter bands. The original Optibeam, featuring three full-size elements on each band, delivers strong forward gain and front-to-back ratio but comes with a high price tag. To address this, a custom design was developed, offering similar performance at a fraction of the cost. Using accessible materials and a simple 1:1 current balun, the homemade version proved highly effective, making it a practical solution.

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.

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 Wanted Alive (TWA) by OH2BUA is an online DX cluster service specifically tailored for digital mode enthusiasts, presenting real-time DX spots with a unique ranking system. Unlike traditional clusters, TWA sorts spots by decreasing DXCC most-wanted ranking, allowing operators to prioritize rare entities. It integrates data from various sources, including PSK Reporter and RBN, to provide a comprehensive view of current propagation conditions for modes like FT8, FT4, and JS8. This approach helps DXers quickly identify and pursue high-value contacts, optimizing their time on the air. OH2BUA's TWA provides a practical application for serious DXers by filtering the noise and highlighting the most sought-after DXCC entities. The service's focus on digital modes reflects the growing popularity of these efficient, low-power communication methods, offering a specialized tool that complements general-purpose DX clusters. By presenting propagation information through the lens of DXCC rarity, TWA assists operators in achieving DXCC awards and improving their overall DXing efficiency, particularly during contests or limited operating windows.

Chavdar Levkov, LZ1AQ, presents an experimental comparison of small wideband magnetic loops, building on his previous work on wideband active small magnetic loop antennas. His research focuses on increasing loop sensitivity by maximizing the short-circuit current, which is directly tied to the "loop factor" M = A/L, where A is the equivalent loop area and L is its inductance. Levkov's methodology involves reducing inductance and increasing area through parallel or coplanar crossed (CC) configurations, comparing these designs against a reference single quad loop of 1 m2 area. Experimental verification included testing three distinct loop types: a simple quad loop, two coplanar crossed (CC) loops, and eight parallel loops, all designed to have a total geometric area of 1 m2. Measurements were conducted at 1.8, 3.5, 7, and 10 MHz using a small transmitter 270 meters away, with a Perseus direct sampling receiver for precise signal level assessment. The results consistently showed that CC loops, particularly Loop 5 (two CC circular loops with 1.44 m2 total area), yielded significantly higher currents, up to 9.1 dB over the reference loop at 3.5 MHz, validating M as a reliable predictor of loop sensitivity. Numerical simulations using MMANA further corroborated the experimental findings, demonstrating an almost perfect correlation between the calculated M factor and the induced loop current for 15 different loop models. Levkov concludes that CC loops offer superior sensitivity for a given loop area, while parallel loops are advantageous for minimizing physical volume. Practical recommendations suggest using loops with an M factor greater than 0.5 uA/pT for quiet rural environments, and he provides a spreadsheet tool, WLoop_calc.xls, to aid in optimizing loop configurations for specific operational needs.

The DIY Power Meter project utilizes the _INA226_ high-side power monitoring chip, paired with an ATtiny85 microcontroller, to measure voltage, current, and power, displaying the results on a 128x32 OLED screen. The INA226 communicates via an I2C interface and is programmed with a calibration factor based on the shunt resistance and current register LSB. The project is designed to handle a maximum current of 500mA using a 0.16ohm shunt resistor, which can be adjusted to a 0.2ohm resistor, reducing the full-scale current range to 409mA with a resolution of **12.5uA**. The shunt resistor dissipates only 33mW at maximum current, making 1/4 watt resistors suitable for the setup. The PowerMeter.ino sketch configures the shunt resistance and maximum design current, automatically calculating the calibration factor. The project can be prototyped on a breadboard using an Arduino Uno, employing the Wire library for INA226 and OLED communication, and the u8g2lib library for the OLED display. For the ATtiny85 version, the Adafruit-TinyWireM and Tiny4kOLED libraries are used. The power meter is independently powered by a 3V CR2032 cell, with power switching options including manual switches or DC switched jacks. The low-side n-channel MOSFET switch configuration is tested but introduces voltage drop issues, making manual switching a more reliable option until a suitable DC switched jack is found. DXZone Technical Profile: INA226 | ATtiny85 | OLED Display | Power Meter

Over 100 FCC districts are analyzed by this resource, providing a predictive database for amateur radio vanity callsign assignments. The system simulates the FCC's application process, calculating the probability of assignment for specific callsigns, such as KD3Q at 94% or N9QC at 97.8%. Data is meticulously organized by FCC district, detailing available, pending, and upcoming callsigns, alongside those currently blocked by renewal or other FCC administrative actions. This allows hams to gauge their chances of securing a desired callsign. The database presents specific application entries, including the date entered, receipt date, process date, the applicant's current callsign, and the vanity callsigns they have applied for. Each entry facilitates examination of predicted outcomes, which categorize potential assignments as assigned, competitive, non-assigned, unneeded, curable, or unknown status. For instance, an application for K7DM clearly shows multiple applicants, indicating a highly competitive assignment scenario. This tool is particularly useful for those seeking a **short callsign** or a **1x2, 2x1, 2x2, 1x3, 2x3, 3x1, 3x2, or 3x3 callsign** that aligns with personal preferences or contest aspirations. It provides a clear, data-driven perspective on the likelihood of obtaining a specific vanity callsign.

Detecting stray RF voltages on station grounds, chassis, and interconnecting cables is crucial for preventing program and hardware failures in the shack. This article details the construction and application of an LED RF V-probe, which offers significantly higher sensitivity compared to conventional neon lamp indicators. The probe leverages two specific properties of modern red LEDs: their ability to glow at microampere currents and their rectification capability at frequencies up to tens of megahertz. The design features a simple circuit with two LEDs, allowing for indication of both positive and negative RF voltage half-waves. The minimum detectable RF voltage is approximately 2 V, a substantial improvement over the 40-60 V threshold of neon bulbs. The resource illustrates the probe's physical construction on a PCB and provides a direct comparison demonstrating its superior sensitivity in detecting RF fields near a coil. Two operational modes are described: a non-contact mode for high RF voltages (above 15-20 V) and a direct-contact mode for measuring lower RF voltages, with a safety caution for the latter. Practical examples show the probe's use in analyzing RF voltage distribution across a radio station setup at 1.84 MHz and 24.9 MHz, revealing insights into common-mode current issues and the effectiveness of mitigation strategies like adding radials.

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.

The **5-Port 12 Volt DC Power Strip Kit (Rev 4)** offers a practical solution for managing shack power distribution, providing one input and five fused outputs. All connections utilize the ubiquitous Anderson PowerPole connectors, a standard for many amateur radio operators, ensuring a clean, organized, and safe way to power multiple 12 VDC transceivers and accessories from a single source. This design mitigates the common issue of tangled wires and overloaded connections in a typical ham shack. Rated for a maximum current of 20 Amps at 12 VDC, the strip incorporates an integrated LED to indicate when external power is applied. Each output is individually fused, a critical safety feature that protects connected equipment from overcurrent conditions without affecting other devices on the strip. This level of protection is essential for preserving sensitive radio gear during operation. Assembly requires basic soldering skills and hand tools, with a high-power soldering iron and wide chisel tip specifically recommended for best results. The kit's compact dimensions of 4.13" x 1.78" allow for flexible mounting via screw holes, making it suitable for various shack configurations and portable operations.

The article details the repair of an Elecraft K3 transceiver experiencing an "ERR 12V" issue, causing reduced output power. The problem, common in these units, stems from inadequate pin strips carrying high DC current to the PA unit, leading to overheating and poor conduction. The author identified the faulty connectors and implemented a bypass using existing PCB pads, effectively rerouting the power and resolving the error. This straightforward fix highlights the importance of robust electrical connections in high-current applications, restoring the K3's full functionality.