Search results

To aid in learning and improving Morse code proficiency, this resource offers an extensive collection of downloadable MP3 audio files. The content includes character practice groups, common words, punctuation, and full-length novels, all rendered in CW. Speeds incrementally increase, catering to both beginners and those aiming to build speed, with options for _Farnsworth_ spacing at lower WPM and standard spacing for higher rates. The resource also provides a Perl script, `gus_morse.pl`, allowing users to generate custom audio files from UTF-8 text. Users can download archives of sequential MP3 files, with options for English, German, Spanish, Esperanto, and Italian content. The audiobooks progress from **5 WPM** to over **40 WPM**, with some archives offering _omnibus_ collections of multiple works. The site emphasizes the importance of consistent daily practice and patient aural observation to develop procedural memory, moving beyond conscious dit and dah counting to direct character recognition. It also details the transition from Farnsworth to normal spacing, aligning with FCC and ARRL recommendations.

Article on tubes and their usage in power amplifiers design. Explain failures of tube in RF power amplifiers, a common problem in the SB-220 SB-221, TL-922 and other amplifiers.

Chronicles technical discussions and operational queries related to various Yaesu amateur radio equipment, primarily from February 2004. Topics include troubleshooting the _FT-101E_ -100v circuit, questions about the FT-990, and inquiries regarding the _VX-7R_ service manual. Operators discuss issues like the FT-101's transmit problems, FT-1000D tuning knob behavior, and the FT-897's linear amplifier control. The archive also contains posts about specific components, such as the 2SC2652 RF power transistor, and requests for parts like FT-221R boards. Users share information on CAT interface cables for the FT-1000D and discuss features of handhelds like the VX-2R and VX-7R. This historical snapshot provides insights into common problems and user-driven solutions for Yaesu gear from that era. Several posts offer items for sale, including an FT-208R and an MD-1 desk microphone, alongside requests to buy specific transverters like the FTV-650B.

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

In this article the author describes some new designs of ferrite loaded chokes for suppressing unwanted common mode currents at HF applied to feed lines like choke baluns, but also in the shack, applied to various coaxial, mains and data cables

A chart presenting the results of impedance measurements made on a variety of common-mode choke implementations across the frequency range 1MHz to 30MHz by G3TXQ

Presents a detailed compilation of **6-meter** voice repeaters operating within the 53-54 MHz segment across Australia (VK) and New Zealand (ZL), providing essential data for local and visiting radio amateurs. Each entry specifies the repeater's output and input frequencies, its assigned callsign (where applicable), the primary service area, current operational status (e.g., operational, under construction, scrapped), and a **Maidenhead grid locator**. The resource also includes the date the repeater was last heard or updated, offering insights into its recent activity. This listing is meticulously maintained by VK2KFJ, who updates entries based on personal observations and confirmed reports from other operators. It serves as a practical reference for hams seeking to utilize the 6-meter band for local communication via repeaters, particularly for those engaged in mobile or portable operations within the specified regions. The data helps operators configure their transceivers correctly for accessing these vital communication hubs. Beyond the repeater details, the page also notes common 6-meter FM voice simplex frequencies, such as the 52.525 MHz international call frequency, and lists historical packet simplex frequencies, though their current operational status is uncertain. This comprehensive approach ensures that operators have a broad overview of 6-meter activity in VK and ZL.

Ground Plane antennas and common mode

A table summarizing common coax cables features

A system designed to automatically tune small transmitting magnetic loop antennas, particularly beneficial for **contest operations** where rapid frequency changes are common. The core of the system involves a PC-based control application, AutoCap, written in C#, which monitors antenna SWR via an external meter and commands a motor interface to adjust the loop's variable capacitor. The software is compatible with Windows and Linux via the Mono framework, offering a graphical user interface for monitoring system status, SWR, power, and motor commands. Key components include one or more magnetic loop antennas equipped with DC or stepper motors for capacitor adjustment, an SWR meter with data output (such as the Telepost LP-100A or a homebrew serial/USB SWR meter), the AutoCap PC software, and a motor interface. The most effective motor interface utilizes an **Arduino-based controller** with custom firmware, providing precise control over both simple DC motors and stepper motors, and supporting features like motor braking for finer adjustments. The system allows for configurable SWR thresholds, pulse widths, and motor effort settings to optimize tuning speed and resolution. Optional radio integration provides frequency hints, enabling the algorithm to learn the relationship between motor actions and resonant frequency, thereby speeding up initial tuning responses. The software also supports antenna profiles, allowing operators to save and recall specific configurations for different loops, including accumulated frequency hint data.

The 2000 CQ WW Multi-Multi operation by the GM0B contest group from Benbecula, Outer Hebrides, Scotland, is documented, providing insights into a significant **DX contest** effort. This resource outlines the station setup, operational strategies, and team composition for a large-scale, multi-operator, multi-transmitter entry. It details the logistical challenges and technical solutions employed to achieve competitive results from a remote island location, a common scenario for **DXpedition**-style contest operations. The page offers a glimpse into the practical application of contest rules and the coordination required for a successful multi-operator effort. It serves as a historical record of the GM0B team's performance in a major international contest, allowing other contesters to compare operational approaches and understand the scale of such an undertaking. The information can be useful for those planning similar contest expeditions or studying past contest strategies.

This page list schedules for the E10 Spy Number shortwave radio station, commonly believed to be run by mossad.

A general article on CMC, common mode choke include a description and tipical usage.

Mitigating RF noise in a mobile operating environment, particularly within a _Jeep TJ_ vehicle, presents unique challenges due to the vehicle's electrical system and chassis characteristics. This resource details practical methods for identifying and suppressing various forms of radio frequency interference (RFI) that can degrade receiver performance for both CB and amateur radio transceivers. It covers common noise sources such as ignition systems, alternators, fuel pumps, and computer modules, explaining how these components generate broadband or specific frequency noise that impacts radio communications. The guide offers actionable solutions, including proper grounding techniques, the strategic use of ferrite beads and toroids on power and data lines, and the installation of bypass capacitors. It discusses the effectiveness of different filtering strategies for DC power lines and antenna feedlines, illustrating how a clean power supply and shielded cabling can significantly reduce conducted and radiated noise. The information presented helps operators achieve a lower noise floor, improving signal-to-noise ratio and enabling clearer reception of weak signals, which is crucial for effective mobile DXing or local ragchewing.

The resource details the construction of a multiband trap-style Inverted-V antenna designed for operation on 3.5 MHz, 7 MHz, 14 MHz, 21 MHz, and 28 MHz. It presents specific winding data for the traps, including the number of turns, wire gauge, and coil former dimensions, crucial for achieving resonance on the target bands. The document provides a parts list and a diagram illustrating the antenna's physical layout and trap placement. It outlines the process for building the traps using PVC pipe formers and specifies the required capacitor values for each trap. The design emphasizes a practical approach to achieving multiband operation with a single feedline, a common goal for HF operators with limited space. The document includes a table with antenna segment lengths for each band, allowing for precise replication of the design. It also offers insights into tuning and adjustment, ensuring the antenna performs optimally across the designated amateur radio bands.

This is another alternative home-brew center connector for a dipole. The parts used are common PVC accesories found at the home supply store.

How to build a QFH (Quadrifilar Helix Antenna) to download images from weather satellites. A complete tutorial on assembling QFH antenna at home with simple and common tools

This resource examines the appropriate use of /M (mobile) and /P (portable) suffixes in amateur radio callsigns, specifically within the context of the UK Amateur Radio Licence. It addresses common ambiguities and challenges in determining operational status, such as operating from a summit or while walking. The discussion references the licence version in force before February 21, 2024, noting that while current regulations recommend but do not specify suffix use, the prior definitions remain relevant for understanding common practice. The content dissects key sections of the licence, including "Notes to the licence" (d)(i-iii) which outlines /A, /P, and /M usage based on location, and "Temporary Location" (jj) which defines /P operations. It also clarifies "Mobile" (17(1)(x)) as operating in or on a vehicle, on a pedestrian, or on a vessel on inland waters. The author provides examples and recommendations for choosing between /M and /P when both might apply, such as when operating from a parked car with a deployed mast or using a handheld on a summit. Historical notes from M1MAJ, G8ADD, and G6MZX are included, tracing the evolution of suffix rules from pre-BR68 days to the 1977 licence version. These historical perspectives highlight how past regulations have influenced current interpretations and persistent myths regarding /M usage. The resource emphasizes making an informed choice based on the licence and communicating the station's operational circumstances clearly.

NU-Tech is a powerful DSP platform to validate and real-time debug complex algorithms, simply relying on a common PC. Thanks to an easy plug-in architecture, the developer can write his own NUTSs (NU-Tech Satellites) in C++ and immediately plug them into the graphical interface design environment.

May 2015 Radcom Article on common-mode chokes that can be used for control cables, phone lines, but mostly on typical HF antenna systems. This article explain what common mode chokes does, why you meay need one, properties common mode chokes should have, how to build and measure performances.

Stop common-mode current when transmitting with an end-fed antenna. Unbalanced antennas are very prone to currents on the outside of the coax.

In this article the author provides some guidelines on how to solve a common problem when stacking different types of yagi antennas on the same mast, limiting the effects on gain and radiation pattern of both antennas

MyAntennas.com offers standard and custom made multiband antennas, Baluns, Common Mode chokes and accessories. All products are designed and made by Danny Horvat, E73M an antenna design engineer formerly employed by Cushcraft Corporation.

Ham Radio cartoons of common situations

6m/2m/70cm Yagi Antenna Built from Old TV Antenna This turned out to be a great little antenna. It works the 6 meter, 2 meter and 70 centimeter bands. You can use one common feedpoint or two seperate feedpoints depending on how you would like to connect this antenna to your transceiver.

A DIY Automatic Band Decoder (ABD) project, designed for dual-radio operation, addresses the common challenge of integrating band data with older transceivers lacking dedicated outputs. This particular build utilizes an AVR AT90S8515 microcontroller and a 16x2 Liquid Crystal Display (LCD) to provide band information, specifically targeting Kenwood rigs via a computer's LPT port. The design aims for cost-effectiveness while maintaining functionality, offering a solution for hams seeking to add automatic band switching capabilities to their station without significant expense. The project outlines the core components required, including the microcontroller, LCD, and an enclosure, noting that the Printed Circuit Board (PCB) fabrication and AVR programming might present challenges for some builders. It details the input requirements, such as a four-pin input and PTT for each radio, along with a 13.8V DC power supply. The decoder provides 2x6 outputs capable of sinking 500mA, suitable for controlling external devices like antenna switches or filters. Despite the original unit being damaged by a lightning strike in 2004, the author confirms its successful operation prior to the incident and mentions plans for a revised version. The resource includes a schematic in PDF format and images of the finished PCB and assembled unit, demonstrating the practical implementation of the design.

Ham radio wire antennas are the most common form of antenna used by ham radio operators. Here you can find hints and tips on diy wire antennas

Presents a construction project for a 1:1 current balun, specifically detailing the _Sorbie Balun and Bottle Choke_ design. The resource outlines the winding technique, employing 4+4 turns of mini coaxial cable on a large ferrite core, and provides insights into the physical assembly. It includes specific material recommendations, such as the type of ferrite and coaxial cable, crucial for achieving the desired impedance transformation and common-mode current suppression. The content covers the practical steps involved in building the balun, from preparing the coaxial cable to securing the windings on the ferrite toroid. It also discusses the integration of the balun into an antenna system, emphasizing its role in maintaining pattern integrity and reducing RF interference in the shack. The resource offers a clear, step-by-step approach, making the project accessible for homebrewers. Illustrations and photographs accompany the text, visually guiding the builder through each stage of construction. The article concludes with performance expectations and considerations for deployment, ensuring the constructed balun functions effectively across the intended frequency range.

Operating the _Icom IC-746_ HF/VHF transceiver often presents specific technical questions, and this resource compiles a comprehensive Frequently Asked Questions (FAQ) document in an ASCII text format. It details common inquiries and solutions related to the rig's functionality, accessories, and potential modifications. The content is structured into distinct sections addressing general information, power supplies, antennas, microphones, keyers, amplifiers, TNC integration, and optional IF filters. The FAQ provides practical guidance on topics such as configuring the internal automatic antenna tuning unit (ATU), selecting appropriate power supplies, and understanding microphone pin-outs. It also delves into advanced subjects like computer control via CI-V, wiring for PSK31 operation, and troubleshooting common issues like low S-meter readings on 2m FM or loose tuning shafts. Specific questions cover the installation of optional IF filters, comparing Inrad versus Icom filters, and optimizing filter combinations for various modes. Furthermore, the document outlines various hardware and firmware modifications, including those for increasing monitor volume, replacing LCD driver transistors, and implementing a "poor man's TCXO." It even touches upon untested modifications, such as replacing PIN diodes in the demodulator. The FAQ also lists manual errata and discrepancies, offering a robust knowledge base for IC-746 owners seeking to optimize their station or resolve operational challenges.

The **TransWorld Antennas TW2010 Traveler HF Portable Vertical Antenna** assembly video provides a visual walkthrough for deploying this popular portable HF antenna. It details the step-by-step process, from unpacking components to final setup, which is crucial for operators preparing for field day operations or DXpeditions. The video focuses on practical aspects, showing how to connect the various elements and secure the antenna for optimal performance. Operators often seek clear assembly instructions for portable antennas like the TW2010 to ensure quick and correct deployment in diverse environments. This visual aid helps clarify potential ambiguities found in written manuals, illustrating the proper handling of the antenna's radial system and telescopic elements. The video serves as a valuable resource for those aiming to achieve efficient operation with the **TW2010 Traveler** in a portable setting. Understanding the assembly sequence can significantly reduce setup time and prevent common errors encountered during initial deployments.

About windom antennas and OCF dipoles, tricks on covering more bands moving feed-points and potential problems. Problems caused by common mode currents in OCF dipoles

The _Sci.Electronics FAQ: Repair: RFI/EMI Info_ document, authored by Daniel 9V1ZV, provides a detailed analysis of computer-generated RFI/EMI, focusing on its impact on radio reception. It identifies common RFI sources such as CPU clock rates (e.g., 4.77 MHz to 80 MHz), video card oscillators (e.g., 14.316 MHz), and even keyboard microprocessors, all of which generate square-wave harmonics across HF and L-VHF regions. The resource outlines a systematic procedure for pinpointing RFI origins, including disconnecting peripherals and using a portable AM/SW receiver with a ferrite rod antenna to localize strong interference sources. The document categorizes RFI mitigation into shielding, filtering, and design problems, offering practical solutions for each. It recommends applying conductive sprays like _EMI-LAC_ or _EMV-LACK_ to plastic casings of radios, monitors, and CPUs to create effective Faraday cages, emphasizing proper grounding and avoiding short circuits. For filtering, the guide suggests using line filters, ferrite beads, and toroids on power and data lines, and small value capacitors (e.g., 0.01 uF for serial/parallel, 100 pF for video) to shunt RFI to ground. It also discusses the use of bandpass, high-pass, low-pass, and notch filters on the receiver front-end or antenna feed to combat specific in-band noise.

Marshall G. Emm, N1FN, meticulously examines iambic keying, dissecting its historical introduction in the late 1950s with transistorized electronic keyers and its purported advantages. The resource defines keying systems, electronic keyers, and various paddle types, including single-lever and dual-lever paddles, clarifying the distinction between iambic keyers and the iambic sending technique itself. It details the two main types of squeeze keying: true squeeze for alternating dot-dash strings and character insertion for specific elements within a character. N1FN critically evaluates the actual efficiency gains of iambic keying, referencing Chuck Adams, K7QO's, keystroke analysis. While a straight key to bug transition yields a 34.1% reduction and a bug to non-iambic keyer offers 16.1%, iambic keying provides only an 11% theoretical improvement. However, considering typical QSO text and Morse code's inherent optimization for common letters, the practical efficiency gain is estimated at a modest 4-6%. The article also highlights how iambic keying's reliance on precise timing gates can impose a speed limit, making it less effective above 40 WPM, where many operators revert to non-iambic methods or single-lever paddles.

Operating a ham station often involves encountering radio frequency interference (RFI), RF feedback, or RF burns, which are frequently misattributed to poor equipment grounding. This resource meticulously dissects these assumptions, asserting that RF grounds on the operating desk often merely mask more significant system flaws. It identifies five primary causes for RF problems, including antenna system design flaws, proximity of the antenna to the operating position, DC power supply ground loops, equipment design defects, and poorly installed connectors or defective cables. The content emphasizes that issues like "hot cabinets" or changes in SWR when connecting a ground indicate substantial RF flowing over wiring or cabinets, a phenomenon known as common-mode current. The article provides detailed explanations of common-mode current generation, particularly from single-wire fed antennas like longwires, random wires, and OCF dipoles, which inherently present high levels of RF in the shack. It also illustrates how vertical antennas, lacking a perfect ground system, can excite feed lines with significant common-mode current. Through simulations, the author demonstrates how a dipole without a proper _balun_ can cause RF problems at the operating desk, showing current patterns and voltage distributions on feed line shields. The discussion extends to the proper application of _RF isolators_ and _ferrite beads_, clarifying their role in modifying common-mode impedance on cable shields and cautioning against their use as a band-aid for fundamental system defects. The resource advocates for correcting the actual source of RF problems, such as antenna system issues or poor connector mounting, rather than relying on internal shack grounding or isolators. It highlights that properly functioning two-conductor feed lines, like coaxial or open-wire lines, should result in minimal RF levels at the operating position, even without a desk RF ground. The author shares personal experience, noting that his stations since the late 1970s have operated without RF grounds at the desks, relying instead on proper antenna system design and feed line integrity.

Chart that present results of impedance measurements made on a variety of common-mode choke implementations across the frequency range 1MHz to 30MHz by G3TXQ

ladder-line is great - extremely low loss, even at high SWR. However, many hams refuse to use it because they are afflicted by common misconceptions

The 160-meter amateur radio band, spanning 1.8 to 2 MHz, was historically the lowest frequency amateur allocation until the introduction of the 630-meter and 2200-meter bands. ITU Region 1 allocates 1.81–2 MHz, while other regions use 1.8–2 MHz. This band, often called "Top Band" or "Gentleman's Band," was established by the International Radiotelegraph Conference in Washington, D.C., on October 4, 1927, with an initial allocation of 1.715–2 MHz. Effective operation on 160 meters presents significant challenges due to the large antenna sizes required; a quarter-wavelength monopole is over 130 feet, and horizontal dipoles need similar heights. Propagation is typically local during the day, but long-distance contacts are common at night, especially around sunrise and sunset, and during solar minimums. The band experienced a resurgence after the LORAN-A system was phased out in North America in December 1980, leading to the removal of power restrictions.

Presents a concise guide for Amateur Radio operators participating in Jamboree-on-the-Air (JOTA), an annual event connecting approximately 500,000 Scouts and Guides worldwide via ham radio. The resource details how to initiate a voice contact, including the use of "CQ Jamboree JOTA" and proper signal reporting with the RST system. It also outlines the typical exchange information, such as name, QTH, Scout rank, and age, encouraging participants to practice their responses. Authored by Bill Wetherill, N2WG, the brochure provides a practical phonetics chart and a comprehensive Morse code dictionary, including punctuation and prosigns like AR and SK. It clarifies rules for third-party operation under the direct supervision of a licensed operator, noting restrictions on international contacts without specific government agreements. Additionally, the guide lists recommended World Scout Frequencies for SSB and CW across 80, 40, 20, 17, 15, 12, and 10 meters, emphasizing courteous operating procedures. It includes a section on common Q-signals like QRM, QRN, and QSL, alongside the Amateur's Code, which stresses considerate, loyal, progressive, friendly, balanced, and patriotic conduct.

Such kind of omnidirectional antenna gives the possibility to be QRV with horizontal polarisation, as commonly used for the CW and SSB section of the 2m band. This actual design shows a 1.3:1 bandwidth of about 150kHz, centered to 144.200MHz.

AO-51 Operating guidelines and introduction

How do two-wire reversible direction Beverages work, an excellent document that explains fundamentals of beverage antennas. This article details the design and performance of a reversible beverage antenna. Leveraging orthogonality between common mode and differential mode currents on a 2-wire line, this antenna facilitates independent reception from both ends. While common mode signals arrive and are summed on a transformer's secondary for common mode reception, differential mode signals induce anti-phase currents, providing individual reception. Various measurements explore impedance, transmission loss, and F/B ratio, highlighting the antenna's effectiveness and areas for improvement. Notably, increasing the antenna's height significantly improved performance.

Common causes of failues, due to wrong clamps. About Guy Anchors

There is a common perception that placing a balun on the input of a tuner causes the balun to work better. The thought is the balun operates with a matched impedance and that reduces balun losses. It also is thought that moving the balun improves balance.

About Ground loops, Wiring Caveat, Basics, Most Prevalent Cause, Common Connections

A synthesized 2.3 GHz Amateur Television (ATV) transmitter design, conceived by Ian G6TVJ, is presented, targeting broadcast-quality video performance on the 13cm band and extending up to 2.6 GHz. The core of the design utilizes a commercial Z-comm Voltage Controlled Oscillator (VCO) that tunes from 2.2-2.7 GHz, providing a +10 dBm output and simplifying RF alignment. This VCO's stability, originally intended for narrowband applications, readily accepts high-frequency video modulation, contributing to the transmitter's robust performance. The exciter stage, incorporating a Mini Circuits VNA 25 MMIC amplifier, boosts the signal to +16dBm, while a Plessey SP4982 prescaler divides the output frequency for the synthesizer. The synthesizer employs a Motorola MC145151 CMOS parallel IC, favored over the common Plessey SP5060 for its superior video modulation characteristics and ease of programming without microprocessors. This choice addresses issues like LF tilt and distorted field syncs often seen with SP5060 designs, particularly when operating through repeaters or over long distances. The MC145151 divides the signal further, enabling precise frequency stepping, with programming handled by EPROMs for channel selection and LED display. The loop filter network, critical for video integrity, was developed through experimentation to prevent the PLL from reacting to video modulation, ensuring a clean transmitted picture. The transmitter incorporates a Down East Microwave commercial power amplifier module, delivering approximately 1.6W output, driven by the exciter through a 3dB attenuator. Construction involves surface-mount SHF components on micro-strip lines etched onto double-sided fiberglass board, housed within a tinplate box. The design boasts no AC coupling in the video path, preserving low-frequency response, a common failing in other ATV transmitters. Performance tests with a 50Hz square wave revealed no LF distortion, and a calibrated "Pulse & Bar" signal showed a near 100% HF response, demonstrating its capability for high-quality ATV transmissions.

The article, "Using 75 Ohm CATV Coaxial Cable," details methods for employing readily available 75-ohm CATV hardline in standard 50-ohm amateur radio setups. It addresses the inherent impedance mismatch and practical considerations, such as connector compatibility, for hams seeking cost-effective, low-loss feedline solutions. The resource specifically contrasts common 50-ohm cables like RG-8, RG213, and _LMR-400_ with 75-ohm hardline, highlighting the latter's lower loss characteristics, particularly at VHF and UHF frequencies. It explores two primary approaches to manage the impedance difference: direct connection with an acceptable SWR compromise and precise impedance transformation. The direct connection method acknowledges that a perfect 1:1 SWR is not always critical, especially when using low-loss coax. For impedance transformation, the article explains the use of half-wavelength sections of coax to reflect the antenna's 50-ohm impedance back to the transmitter, noting its single-frequency effectiveness. It also briefly mentions transformer designs using toroid cores and a technique involving two 1/12 wavelength sections of feedline for broader bandwidth. The content further clarifies the concept of _velocity factor_ for calculating electrical versus physical cable lengths, providing a generic formula for precise length determination. It notes that while half-wave matching is practical for 10 meters and above, it can result in excessively long runs for lower bands like 160 meters, potentially adding **250 feet** of cable. The article also mentions achieving a usable bandwidth of 28.000 MHz up to at least **28.8 MHz** on 10 meters with specific transformation techniques.

Aggregating real-time contest scores, this online scoreboard serves as a central hub for participants and spectators to monitor live progress during amateur radio competitions. It directly interfaces with widely used contest logging programs, collecting score data as operators make contacts. The platform then processes and displays these scores on dedicated contest pages, offering an immediate overview of standings. Supporting a diverse range of **DX contests**, the system accommodates various operating modes and rulesets. It facilitates score tracking for events like the YB DX RTTY, RSGB Commonwealth (BERU), EA PSK63, and the South America 10 Meter contest, among others. This functionality allows contesters to gauge their performance against competitors instantaneously, fostering dynamic participation. The scoreboard's integration with multiple contest log software applications ensures broad compatibility, making it accessible to a significant portion of the contesting community. It provides a crucial service by centralizing score visibility, enhancing the competitive experience for **amateur radio operators** worldwide.

How to interface the Icom IC-7300 to RF Power amplifiers. Menu settings, cable connections and recommendations on how to avodi common errors that could even damage either the amplifier or the IC-7300

The CAT and audio interface version 3 project by PA5CA presents a comprehensive solution for integrating amateur radio transceivers with computer sound cards, facilitating digital mode operation and CAT control. It includes detailed schematics for the interface circuitry, illustrating the isolation transformers for audio paths and optocouplers for CAT data lines, ensuring robust electrical separation between radio and PC. The resource also provides PCB layouts, enabling constructors to fabricate their own boards for this specific design. The project outlines the component selection and assembly process, emphasizing the use of readily available parts to build a reliable interface. It addresses common challenges in sound card interfacing, such as ground loops and RF interference, through its isolated design. This construction guide offers practical insights into building a functional interface, making it suitable for hams interested in DIY radio accessories for digital modes like FT8, RTTY, and PSK31.

1.5 dB of matched line loss can be calculated for a given transmission line using this online tool, which employs a model calibrated from empirical data. The calculator allows radio amateurs to input specific transmission line types, such as _RG-8_ or _RG-58_, and then determine the expected signal attenuation. This is crucial for optimizing antenna system efficiency and understanding power delivery to the radiating element, especially for HF and VHF operations where feedline losses can significantly impact performance. Beyond matched loss, the calculator also provides an estimate for mismatched loss if the Standing Wave Ratio (SWR) is specified. This feature helps operators quantify the additional power loss due to impedance discontinuities between the transceiver, feedline, and antenna, which is a common concern in amateur radio installations. Accurate loss calculations are vital for effective station design and for predicting actual radiated power. The tool's utility extends to various operating scenarios, from fixed station setups to portable deployments, aiding in the selection of appropriate feedline lengths and types to minimize signal degradation. Understanding these losses is a fundamental aspect of maximizing the effectiveness of any amateur radio antenna system.