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All Band HF Doublet for operation over all HF bands including 160m.

The PDF document, titled "J-Poles," presents various J-pole antenna designs covering the 50 MHz to 450 MHz frequency range. It includes construction details for several specific bands, such as a 6-meter J-pole, a 2-meter J-pole, and a 70-centimeter J-pole. The content outlines the fundamental principles of J-pole operation, including the quarter-wave radiator and half-wave matching stub. Each design features specific dimensions for elements like the radiator length, stub length, and spacing, often expressed in inches. The document also discusses feeding arrangements and impedance matching considerations inherent to J-pole antennas. It provides practical guidance for homebrewing these antennas using common materials like copper pipe or wire elements. The resource offers insights into the advantages of J-poles, such as their omnidirectional pattern and ease of construction, making it a practical reference for radio amateurs interested in VHF/UHF antenna projects.

This webpage describe how to set up the Signalink USB interface and Yaesu FT-857D for digital operations by NA4IT

For radio amateurs seeking compact and efficient antenna solutions, particularly for restricted spaces or noise reduction, HF loop antennas present a viable option. This resource compiles several articles from the ARRL, detailing the theory, design considerations, and practical construction of various loop configurations. Topics include small transmitting loops, receiving loops, and multi-band designs, often emphasizing their performance characteristics such as directivity, bandwidth, and impedance matching. The collected articles provide insights into the comparative performance of different loop geometries, such as circular versus square loops, and discuss the impact of conductor size and tuning methods on efficiency. Practical applications are explored, including their use in portable operations, stealth installations, and urban environments where noise mitigation is critical. The content often includes construction diagrams, parts lists, and performance data derived from modeling or field tests, enabling hams to replicate or adapt the designs for their specific operating conditions.

FDLog, a Python-based freeware application, addresses the challenge of synchronized logging for multi-station Field Day operations. It facilitates real-time data sharing across a wireless network, enabling operators to monitor band status and active transmitters at a glance. The software's input system is optimized for minimal keystrokes, streamlining the logging process during intense contest periods. Key features include database synchronization over a wireless network, ensuring all connected computers maintain identical log data. FDLog also incorporates a time synchronization function, designed to keep client programs within a second of a designated master machine, mitigating issues previously encountered with NTP. This internal clock sync can be optionally disabled if not required by the operating setup. Developed initially on Windows 2000, FDLog has demonstrated compatibility with _Linux_ and _macOS_ environments, though some font rendering issues may occur on the latter. The program assists in preparing the ARRL Field Day entry form, simplifying the submission of contest results. User feedback and ARRL rule changes drive ongoing development, with a discussion list available for community support and input.

One specific challenge in the KazShack, operating Single Operator Two Radios (SO2R), involved sharing a K9AY receive antenna between two transceivers without direct RF connection or manual feedline swapping. The solution, detailed in this project, adapts the **W3LPL RX bandpass filter** design to split 160m and 80m signals, feeding them to separate radio inputs while maintaining isolation. This approach also addresses the issue of strong broadcast band interference from a nearby 50KW WPTF transmitter on 680kc. The construction utilizes T-50-3 toroids and NP0 ceramic capacitors, built in a "dead bug" style on copper clad board. Each band's filter coils are identical and resonated to the desired frequency using an MFJ-259 antenna analyzer. A single DPDT relay, controlled by a remote toggle switch mounted on an aluminum panel, facilitates quick band switching between radios, simplifying low-band operations. While some signal loss is noted, the expected lower noise levels from the receive antenna are anticipated to compensate, potentially reducing the need for constant volume adjustments during toggling between transmit and receive antennas.

A GSM1800 Moxon Square antenna project is presented, detailing its construction using three 1.5mm copper wire pieces for the reflector and dipole elements. The design inherently offers a 50-ohm feedpoint impedance, allowing direct connection to 50-ohm coax without complex matching networks like baluns or gamma matches, which are prone to high attenuation at 1.8 GHz if not precisely built. The resource includes a construction plan, expected **SWR plots**, and **radiation patterns** for the GSM 1800 band, specifically covering the 1710-1785 MHz transmit (red zone) and 1805-1880 MHz receive (blue zone) segments. The SWR remains below 2:1 across the entire GSM 1800 band, with the main lobe consistently achieving 5-6 dBi gain. While the radiation pattern shows some changes across the band, these primarily affect the back of the antenna, maintaining consistent forward gain. Practical considerations for high-frequency operation are emphasized, such as minimizing coax length (e.g., under 1 meter for RG-174) and selecting appropriate connectors like N, SMA, or BNC to mitigate significant attenuation. The article also discusses direct connection to the phone's RF PCB for minimal loss and notes observed signal strength variations with antenna orientation despite crossed polarization at cell sites.

The **70cm Moxon Beam** project outlines the construction and testing of a compact, directional antenna for the 432 MHz band. G3XBM recounts his early 1980s experience with a 4W FM321 transceiver and a Jaybeam 48-element TV antenna, which provided a baseline for his later UHF antenna experiments. This project focuses on a simpler, yet effective, design for local and regional contacts, emphasizing ease of construction and practical field results over complex theory. The article details the specific dimensions and materials used for the Moxon rectangle, including 6mm diameter aluminum tubing for the elements and a PVC boom. G3XBM notes that the antenna was built for portable use, making it lightweight and easily deployable for field operations. The feedpoint impedance was measured at 50 ohms, ensuring a direct match without the need for an external tuner, which simplifies setup. Performance tests included comparisons against a commercial 5-element Yagi, revealing that the Moxon provided comparable forward gain and an excellent front-to-back ratio, crucial for reducing local QRM. The author's observations confirm the Moxon's reputation as a robust performer for its size, suitable for both fixed and portable 70cm operations.

A Moxon rectangle antenna design for the 11-meter band is presented, offering a compact and lightweight solution for directional HF DX operation. This two-element parasitic array, popular among amateur radio enthusiasts, provides considerable directional gain and lower noise on horizontal polarization. The design is suitable for both 27 MHz Citizens Band (CB) and the lower portion of the 28 MHz amateur radio band, making it versatile for operators interested in either service. Construction can utilize materials like bamboo, squid poles with wire elements, or aluminum tubing on a central boom. The article includes a plan view diagram with specific dimensions (A-E) in centimeters and inches for building the antenna, such as a 392.09 cm (154 3/8 inch) driven element. The Moxon configuration inherently presents a 50 Ohm load to the transceiver, often eliminating the need for an external matching unit or balun. Performance data for an antenna mounted at approximately 30 feet indicates a gain of 10-11 dBi and a frequency range of 27.300 MHz to 28.300 MHz. The design is noted for its excellent front-to-back rejection, with tested signal drop-offs from S5-S7 to S2 when turned, demonstrating effective suppression of unwanted signals.

A simple 40 meter CW transmitter, it sports full break-in operation and 250 mW of output power.

Presents a construction project for a linear-loaded 40-meter rotatable dipole, detailing the design evolution from mid-element coils to 300-ohm twinlead loading. It covers material selection, including repurposed fishing poles and EMT conduit, and outlines the assembly process for the antenna elements and mounting plate. The resource provides specific measurements for element lengths and linear loading sections, along with SWR plots demonstrating the antenna's resonance at 7.035 MHz with a 1.1:1 SWR, and bandwidth up to 7.120 MHz below 2:1 SWR. The article documents the antenna's performance during various RTTY and CW contests, including the SARTG RTTY and SCC RTTY contests in August 2006, and the ARRL DX CW and CQWW WPX RTTY contests in February 2007. It reports successful operation at 500-1000W, noting improved performance after replacing a faulty coax cable. Specific DX contacts from British Columbia, including stations in Europe and South Africa, are listed, illustrating the antenna's capability despite its shortened length and relatively low height of 55 feet. The content highlights practical considerations such as weatherproofing the connections and supporting the fiberglass elements to prevent sagging. It also includes a brief comparison to an inverted-V at similar height and a ground-mounted vertical, noting the rotatable dipole's quieter reception. The author shares insights into the iterative design process and tuning adjustments made to achieve optimal resonance.

TR4W is a contest logging software package supporting over **180** amateur radio contests. The program operates on Windows 7 to windows 11 operating systems. It supports CW keying via serial port, LPT port, or Winkey, with CW speeds ranging from 1 to **99** WPM. Paddle input via LPT port enables the program to function as a keyer, with paddle input aborting computer-generated CW. PTT support includes programmable delay. The software incorporates automatic super check partial and call checking, along with an expanded .DTA database format for names, QTH, grid, and SS check information. A band map displays color-coded aging data. The software features a built-in telnet DXCluster interface, automatically inserting spots into the band map. It supports RTTY operation via the MMTTY engine and includes WAE QTC support for both European and non-European stations. TR4W provides radio interfacing for Elecraft, Icom, Japan Radio, Kenwood, Ten-Tec, and Yaesu transceivers, utilizing serial or USB-to-serial adapters. Networked multiple-rig operation is supported through a client-server model using TCP/IP protocol. Integrated two-radio support (SO2R) is present. The program includes on-the-fly MP3 recording and log backup to USB drives or selected HDD folders. It uses the standard CTY.DAT file for country and beam heading data.

Over two decades of historical DX spots and news are archived on this Japanese resource, providing a retrospective look at amateur radio propagation and activity across various bands. The content is organized chronologically, with separate sections for _50MHz_, _HF DX_, _144MHz_, _EME_, and Satellite clusters, detailing spot data from as early as 1996 through 2014. This extensive archive serves as a valuable historical record for analyzing long-term propagation trends and significant DXpeditions from a Japanese perspective, offering insights into band openings and rare entity activations. The resource also includes links to other DX news sites like _425 DX News_ and _Ohio/Penn DX Bulletin_, along with QSL manager lookups and callbook services, enhancing its utility as a comprehensive DX information hub. While the primary cluster data is historical, the compilation of external links points to active resources for current DX operations. This makes it a useful reference for contesters and DXers researching past conditions or seeking information on specific DX entities and their QSL routes.

Examines the historical landscape of "boat anchor" amateur radio equipment manufacturers, focusing on the technical innovations and market dynamics that shaped the industry from the pre-WWII era through the transition to SSB. It details the origins and key product lines of prominent U.S. companies like _Collins Radio Company_, _Central Electronics_, and _Barker & Williamson_, highlighting their contributions to receiver and transmitter design. The resource contrasts early AM technology with the advent of SSB, explaining the circuit changes required in receivers and the complete rethinking needed for transmitters. It discusses the impact of military contracts on company survival and the eventual shift towards smaller, self-contained transceivers. Specific examples, such as the _Collins R-390/URR_ receiver and the _Central Electronics 100V/200V_ broadband transmitters, illustrate the engineering prowess and design philosophies of the era, offering insights into their operational characteristics and enduring appeal among collectors.

Constructing a portable, high-gain antenna for _AO-40_ satellite operations presents unique challenges, particularly regarding mechanical stability and parabolic accuracy. This resource details the build of a 1.2-meter "brolly dish" antenna, utilizing a non-conducting fiberglass umbrella frame as its foundation. The project outlines a method for achieving a parabolic shape using stressed aluminum fly screen mesh, guided by practical geometry and a temporary dowel template. Key steps include selecting an appropriate umbrella with a suitable f/D ratio (ideally >0.25), removing the original fabric, and precisely cutting and attaching eight segments of fly screen to the struts to form the reflective surface. The construction process, which took approximately five hours for the author, _G6LVB_, resulted in a dish with an f/D of 0.27 (depth=270mm, diameter=1160mm, f=310mm). The article also describes a modification to a _TransSystem AIDC_ feed, incorporating a PCB reflector behind the dipole for easier mounting. Performance tests at a squint angle of 15 deg and a range of 50,000km yielded a signal-to-noise ratio of 33dB on the S2 beacon and 23dB for SSB signals, indicating strong reception. The author notes that the modified umbrella may not close fully without risking surface disfigurement.

R25Log is a DOS-based universal logging program designed for active amateur radio operators, combining standard logging functionalities with several new features. It provides a wealth of information, input, and evaluation possibilities, having been tested and proven in real-world QSO operations. The software supports various operating modes and is specifically tailored for efficient log management. The program's capabilities include comprehensive logging for DXing and contesting, offering detailed input fields and robust evaluation tools. Its _freeware_ status and DOS Shell environment make it accessible for users with legacy systems or those preferring a lightweight logging solution. The design emphasizes practical application, allowing operators to manage their logbooks effectively and analyze their contact data, contributing to improved station performance and award tracking.

Presents the amateur radio activities and interests of Kote, operating as 4L4KW. The page features a collection of external links relevant to the ham radio community, including references to other callsigns such as 4L1BR, 4L1W, 4L4MM, and 4L/ZL1RS, indicating potential connections or shared interests within the Georgian amateur radio scene. It also lists several well-known ham radio resources like QRZ.com, DXzone.com, and Contesting.com, suggesting an active engagement with DXing and contesting. The resource includes links to major amateur radio equipment manufacturers such as Icom, Yaesu, and Kenwood, which implies an interest in modern transceivers and station setup. The mention of DX-Summit and "fixed activity on Ham bands" further reinforces a focus on making contacts and participating in on-air operations. The page serves as a digital hub for 4L4KW's ham radio presence.

The Wireless Institute of Australia (WIA) provides an official directory and database of Australian amateur radio repeaters, detailing their locations, frequencies, and operational status. The resource includes downloadable files in PDF and CSV formats, along with a _Google Earth KMZ_ file for visualizing repeater sites across Australia, including Amateur, CB, and Marine repeaters. It also references external resources for various digital modes such as _IRLP_, _Echolink_, _D-STAR_, P25, Fusion, and DMR, providing links to their respective information sites. The WIA repeater data is cross-referenced with the _ACMA database_ to ensure accuracy, with updates typically occurring twice a year. The directory employs a color-coding system, where purple indicates repeaters carrying the WIA broadcast or callback channels, and a 'W' status denotes operational repeaters with the weekly WIA broadcast. The resource also outlines policies for removing unlicensed or non-operational repeaters from the PDF listing after specific timeframes, while retaining them in the CSV file for potential reinstatement.

Lowering an NVIS or N.V.I.S. antenna very close to the ground enhances NVIS operation

The WT0G crazy W dipole, a solution for 160 meter operations

PA is a JAVA software package containing several programs, SW/VHF/UHF Logbook (imports format from RADIOMAN, VMT), Log conversion to HTML format, Import and export functions for RADIOMAN, CT RES files, BV QSL Labels, CSV etc. Internet DX-Cluster support, Keeps track of your worked Callsigns, Checks your worked Grid Squares per band, Databases for worked Grids and Callsigns Uses K1EA CQWW.CTY country file, Easy command line version for terminal operation Moontracking as clock, Pathloss calculation

A 20-meter vertical _Moxon_ antenna, designed for portable operation, is detailed with specific dimensions for its driven and reflector elements. The project outlines the construction process, including the use of PVC pipe for the frame and #14 AWG insulated wire for the elements. The antenna's compact size and directional characteristics make it suitable for field day operations or limited space environments, offering a gain of approximately 5.5 dBi and a front-to-back ratio of 20 dB. Testing revealed a 1.2:1 SWR at 14.250 MHz, demonstrating good impedance matching across the target frequency range. The _Moxon rectangle_ design provides a clean radiation pattern with minimal side lobes, which is advantageous for reducing QRM from unwanted directions. This build offers a practical solution for hams seeking a lightweight, easily deployable directional antenna for 20 meters without the complexity of a full-sized Yagi.

The Maik Uniform France website, established on March 27, 2000, serves as a central hub for French CB radio operators interested in DXing. It provides a platform for sharing DX news, logging contacts, and distributing relevant software tools. The resource caters to various CB DX groups, including Papa Alfa Tango, Wisconsin Michigan, Charly Tango, Oscar Sierra, Big Time Operators, WAC Club, Azteca DX, and TX&RX Group, fostering a community around long-distance CB communications. This online presence facilitates the exchange of operational information and resources among CB enthusiasts. While primarily in French, an English option is available. The site's content structure supports the practical application of CB DXing by centralizing information on recent DX activity and providing utilities, thereby assisting operators in improving their DXing capabilities and staying informed about the CB DX scene.

The DL2NBY Contest Calendar, leveraging the Google Calendar system, presents approximately 400 **HF amateur radio contests**, detailing their dates and rules. It covers a broad spectrum of operating modes, including CW, SSB, and various digital modes like RTTY. The calendar integrates contest information from major organizations such as ARRL and DARC, providing a centralized repository for contest operators. This resource offers the capability to integrate contest events directly into a user's personal Google Calendar, streamlining contest planning. It functions as a comprehensive schedule, allowing operators to review upcoming events and prepare for participation across different bands and modes. The calendar's structure facilitates quick access to contest specifics, aiding in strategic contest operation.

The Pocket Loop is a small magnetic loop antenna designed for a carry anywhere operation, it disassembles in 33 centimeters pieces that can be carried even on an attach handbag.

The San Diego Six SHooters Amateur Radio Club, established in April 2001, is dedicated to promoting all modes of operation on the Six Meter Amateur Radio Band.

The ZS6BKW antenna, a popular multiband wire antenna, offers improved band matching compared to the traditional G5RV. This construction guide details the process, beginning with specific dimensions: 13.11 meters (43 feet) for the 450-ohm ladder line and initial dipole arm lengths of approximately 14.8 meters each. It emphasizes the critical role of an _antenna analyzer_ for accurate tuning, particularly for determining the velocity factor of the ladder line and achieving a 1:1 impedance match. The article outlines the materials required, including a 1:1 current balun, 450-ohm window line, wire for the dipole arms, and a 50-ohm non-inductive resistor for testing. It provides a step-by-step procedure for cutting the ladder line to its electrical half-wavelength, explaining how to calculate the velocity factor using measured and free-space frequencies. For instance, a measured 50-ohm impedance at 12.54 MHz with a calculated free-space half-wavelength frequency of 11.44 MHz yields a velocity factor of 0.91. Final adjustments involve hoisting the antenna to its operational height and fine-tuning the dipole arm lengths to achieve optimal SWR, specifically targeting 14.200 MHz. The _ZS6BKW_ design is noted for its performance on 80m, 40m, 20m, 10m, and 6m, though it is not optimized for 15m operation. The author, _VK4MDX_, shares practical tips for durable construction using stainless steel wire and cable clamps.

A 7MHz Full wave loop antenna in diamond shape for field day operations made with three 31 foot Jackite poles

Presents the design and performance of a 4-element wire Yagi antenna for the 40-meter band, building upon VE3VN's earlier 3-element switchable wire Yagi. The resource details the antenna's evolution, highlighting the transition from a 3-element to a 4-element configuration and the resulting improvements in gain and front-to-back ratio. It provides specific insights into the antenna's construction and expected operational characteristics. VE3VN shares insights from field results, noting the antenna's performance on 40 meters. The discussion includes the antenna's pattern and matching characteristics, crucial for any DXer or contester looking to optimize their signal on this popular HF band. The author's experience with the previous 3-element design informs the enhancements made to this 4-element iteration. The article includes a visual representation of the antenna's current view, offering a practical perspective on its physical layout. It serves as a valuable reference for hams considering a directional wire antenna for 7 MHz operations, demonstrating a practical approach to achieving enhanced directivity and gain.

The 11-meter band, often associated with Citizens Band (CB) radio, presents unique challenges and opportunities for long-distance communication, particularly for operators interested in DXing. This group facilitates discussions and information exchange among enthusiasts who operate on this frequency, often utilizing single-sideband (SSB) modulation for improved range and signal clarity compared to traditional AM CB operations. The community provides a platform for members to share experiences, technical insights, and propagation reports relevant to 27 MHz operations. Members engage in discussions covering various aspects of 11-meter DX, including antenna configurations, transceiver modifications, and operating techniques to maximize signal propagation across continents. The forum serves as a central hub for coordinating contacts, sharing QSL information, and celebrating successful long-haul QSOs. Specific topics often include optimizing power output, reducing noise, and understanding solar cycle effects on 27 MHz. The group's activities extend to organizing virtual gatherings and promoting ethical operating practices within the 11-meter DX community. It supports both seasoned operators and those new to the band, fostering a collaborative environment for exploring the capabilities of CB radio beyond local communications.

This resource, "Transistor Audio Preamplifier Circuits," offers comprehensive design guidelines for constructing **bipolar transistor** audio preamplifiers. It delves into critical aspects such as quiescent current setting, voltage gain calculation, and the impact of various component choices on circuit performance. The content provides several _schematic diagrams_ illustrating different preamplifier configurations, including single-stage common emitter and two-stage designs, alongside explanations of their operational characteristics and practical implementation considerations. The analysis extends to frequency response, noise performance, and distortion, providing insights into optimizing these parameters for specific audio applications. The resource presents calculated gain figures for various stages, demonstrating how to achieve desired amplification levels. It also discusses the importance of proper power supply decoupling and input/output impedance matching, crucial for integrating these preamplifiers into larger audio systems or ham radio transceivers. The practical application of these designs is evident in their suitability for microphone preamplifiers or general-purpose audio amplification.

80M field expedient antenna, suitable for NVIS operations

Whether we are tuning up homebrew equipment, checking antenna VSWR, adjusting a linear amplifier, or just monitoring output power during a contest, almost all aspects of ham operation can use a power meter. Paul Wade W1GHZ

The W4NFR 40-meter mobile vertical antenna project details the construction of a mobile antenna system, drawing inspiration from a July 2011 QST article by VE6AB. The design simplifies the top hat by integrating an 8-spoke top hat from Tar Heel Antenna. The resource outlines the tuning process, which involves adjusting the L1 coil for the desired band segment and then fine-tuning SWR with an L2 coil at the feed point. The author achieved a 1:1 SWR at 7.150 MHz with this configuration. The project includes specific instructions for adding anti-sway supports to ensure stable operation and reduce physical stress on the ball mount during vehicle motion. Visual aids such as drawings of the 40-meter mobile antenna, detailed views of the coil and top hat assembly, and an illustration of the ball and spring mount are provided to guide the builder through the construction and installation phases. The content focuses on practical implementation and tuning for optimal performance on the 40-meter band.

Demonstrates the design and construction of a compact, portable multi-band mini-delta loop antenna, specifically optimized for /P (portable) operations from remote locations like Scottish islands. The resource covers the theoretical underpinnings of half-wave loops, contrasting closed and open configurations, and then details the application of a folded dipole principle to achieve a 50-ohm match for direct coax feed. It presents empirical formulas for calculating element lengths, considering the velocity factor of common wire types, and provides a detailed example for a 20m (14.175 MHz) version. The article includes a comprehensive table of dimensions and allowances for a five-band (20m, 17m, 15m, 12m, 10m) mini-delta beam, along with construction hints for the central support and balun. It specifies a 1:1 trifilar balun wound on a ferrite rod and describes the antenna adjustment process using an _MFJ-259B Antenna Analyser_. Initial test results indicate an SWR of 1:1 at resonance and a bandwidth of approximately 240 kHz on 20m, even at a low height of five feet above ground. The distinctive utility lies in its focus on a practical, easily deployable beam antenna for portable DXing, offering a viable alternative to more complex or larger arrays.

NetLogger displays 6 currently active nets, including the 3838 Breakfast Club on 80 meters SSB and the CornCobNet on 40 meters SSB, providing real-time updates every 20 seconds to monitoring participants. It functions as a specialized logging program designed for amateur radio nets, facilitating the transmission of check-in data via the internet. The system lists net name, frequency, band, mode, server, start time (UTC), elapsed time, number of subscribers, and the callsign of the operator who opened the net. The platform details specific net operations, such as the Florida AM Group on 3.885 MHz AM and the GRAVEYARD NET on 3.967 MHz SSB, illustrating its application across various **HF** bands and modes. NetLogger's utility extends to viewing past nets and offers a **Groups.io** integration for community interaction. It provides a practical solution for organizing and participating in amateur radio nets, offering a centralized system for tracking participants and net activity. The resource details specific net operations, such as the Florida AM Group on 3.885 MHz AM and the GRAVEYARD NET on 3.967 MHz SSB, illustrating its application across various HF bands and modes.

The Vee Beam antenna project presents a versatile solution for hams, enabling operation across all eight High Frequency bands (80m to 10m) with significant gain on 20m to 10m. This easy-to-construct antenna utilizes two long wires at an angle, enhancing directional performance and minimizing ground losses. With a low visual profile, it is discreet and effective for various applications. The design allows for optimal leg lengths and included angles, ensuring robust performance while maintaining simplicity in construction and operation. The V Beam antenna is an aerial that you can use on all eight High Frequency amateur bands (80, 40, 30, 20, 17, 15, 12 and 10m) with an antenna tuner, and which gives significant gain on the five bands from 20 to 10 meters band.

The Japanese Amateur Radio Teleprinter Society (JARTS) serves as a central hub for RTTY and PSK31 enthusiasts in Japan, providing essential information regarding its annual JARTS RTTY Contest. The resource outlines contest rules, exchange parameters, and scoring specifics, enabling participants to prepare effectively for the event. It also offers insights into the club's broader activities and its role in promoting digital mode operations within the amateur radio community. The site details the contest's operational periods and categories, which typically include single-operator, multi-operator, and SWL entries, often with power output classifications. Participants can find guidelines for log submission and result publication, ensuring adherence to the contest's administrative requirements. The JARTS RTTY Contest is a significant event for digital mode operators, drawing participation from across Asia and beyond. Beyond contest specifics, the resource provides historical context for JARTS, highlighting its foundational role in Japanese amateur radio digital communications. It serves as a primary point of contact for members and prospective participants, fostering engagement in RTTY and PSK31 modes.

This article presents a technical investigation into spurious emissions from the Yaesu FT-847 transceiver when operating on the 70MHz (4-meter) band. The author discovered significant problems with both factory "UK spec" and modified units. Spectrum analysis revealed that when transmitting at 70.2MHz, the radio produces numerous spurious signals, with the most prominent emission at 45.6MHz measuring only 3dB below the fundamental frequency. The study also documents poor power efficiency on 4m (10.3% at 30W output) compared to 6m operation (23.5% at 30W). Tests verified that jumper configurations had no effect on filter selection. The author warns that using these radios on 4m may violate license conditions due to excessive spurious emissions.

Presents a dynamic, searchable database of shortwave broadcast schedules from around the world, enabling users to locate active stations or plan listening sessions based on scheduled transmission periods and frequencies. The resource details specific station names, such as _Radio Habana Cuba_, _Deutsche Welle_, and _All India Radio_, alongside their operational times and assigned kilohertz frequencies. It also incorporates a distance calculator, which leverages geographical coordinates to estimate propagation paths, though it notes occasional data inaccuracies leading to transmitters appearing in oceanic locations. The platform's development log highlights continuous updates, including the integration of new seasonal schedules like "A24 frequencies" and "B23 schedule," reflecting the fluid nature of shortwave broadcasting. It documents challenges with geolocation services, particularly concerning Google API changes that impacted distance calculations and required user-side browser configuration adjustments for optimal functionality. The site owner, VAXXi, frequently communicates these technical adjustments and database updates, often acknowledging user contributions and donations. Distinctively, the resource provides a historical perspective through its update archives, illustrating the evolution of shortwave listening over more than a decade since its inception in 2011. It also mentions specific events, such as the BBC adding shortwave broadcasts for Ukraine on 5875 kHz and 15735 kHz, demonstrating its responsiveness to global events impacting broadcast schedules. The site's commitment to user feedback is evident in its bug reporting and feature request mechanisms, contributing to its ongoing refinement.

A 2m Moxon antenna project, designed for the 145 MHz amateur radio band, provides a compact, directional solution for VHF communications. This resource details the construction process, specifying materials like PVC pipe for the frame, copper wire for elements, and a SO-239 connector for the feedpoint. The design emphasizes ease of build for hams seeking a gain antenna with good front-to-back ratio for local ragchewing or contesting. The project outlines precise element lengths and spacing, crucial for achieving the desired impedance and radiation pattern. It includes a visual representation of the antenna's dimensions and assembly, allowing for straightforward replication. The Moxon's inherent characteristics offer a practical alternative to larger Yagi arrays, particularly for portable operations or restricted spaces, while still delivering effective directivity and gain.

The document provides a detailed guide on modifying an inverted-L antenna to include the 160 meters band. This enhancement allows amateur radio operators to utilize the lower frequency effectively, which is crucial for long-distance communication, especially during the night. The inverted-L design is popular due to its compact size and ease of installation, making it suitable for various environments. By adding top band capabilities, operators can engage in DXing and contesting on 160m, expanding their operational range and opportunities. The guide includes practical tips and considerations for construction, ensuring that the antenna maintains its performance across the extended frequency range. It discusses the necessary adjustments and materials required for the modification, along with potential challenges and solutions. Whether you are a seasoned operator or a beginner, this project can enhance your station's capabilities, allowing for more versatile operations and improved signal quality on the 160m band.

A 500-watt mobile antenna project details the conversion of an old 10m hamstick into a highly efficient, multiband "bugstick" for HF operation. The core modification involves replacing the original coil with 25 turns of 6 turns-per-inch, 1.5-inch diameter coil stock, fabricated from #14 wire. This design, intended for a 3-magnet mount on a vehicle cab, achieves resonance on multiple bands by shorting out specific turns on the coil, similar to a **bugcatcher** antenna. Measurements taken with an MFJ-259 analyzer on a GMC pickup show 0 turns shorted for 20 meters (14.2 MHz), 10 turns for 17 meters, 16 turns for 15 meters, 19 turns for 12 meters, and 23 turns for 10 meters. The construction emphasizes using UV-resistant tie-wraps and #14 solid wire with crimp lugs for robust RF connections, bypassing the fiberglass rod for current flow. A bonus section details a 40-meter version, utilizing 48 turns of 8 TPI, 2-inch diameter coil stock.

DX Finder presents a real-time DX cluster service tailored for amateur radio operators engaged in DX chasing and contesting. The platform aggregates DX spots, Reverse Beacon Network (RBN) data, and PSK Reporter information, displaying current activity across various amateur bands. It provides a centralized interface for monitoring propagation conditions and identifying rare DX entities, aiding operators in making timely contacts. The service integrates multiple data streams to offer a comprehensive view of global amateur radio activity. Users can access real-time spotting data, which includes callsigns, frequencies, modes, and signal reports, facilitating efficient station operation. The inclusion of RBN and PSK Reporter data enhances situational awareness, allowing operators to assess band openings and signal paths more effectively. DX Finder supports both web and Telnet access, catering to different operational preferences. It also features a dedicated JOTA cluster, specifically designed to support the Jamboree On The Air event.

The **2M Moxon antenna** design presented operates at 144 MHz, providing a compact, directional solution for VHF communications. Construction involves aluminum tubing for the elements, with specific dimensions for the driven element and reflector to achieve optimal performance. The design aims for a good front-to-back ratio and a relatively low SWR across the 2-meter band, making it suitable for portable or fixed station use where directivity is beneficial. Element lengths are critical for proper resonance and pattern. The driven element measures approximately 38.5 inches, while the reflector is slightly longer at 40.5 inches. Spacing between the elements is 12 inches, forming the characteristic Moxon rectangle. This configuration yields a gain of about 5.5 dBi and a front-to-back ratio exceeding 20 dB, which is advantageous for reducing interference from unwanted directions. Feedpoint impedance is close to 50 ohms, allowing direct connection to coaxial cable without complex matching networks. The antenna's lightweight structure, typically under 2 pounds, facilitates easy deployment and rotation, making it a practical choice for field operations or as a compact home station antenna.

Codec2, an open-source speech codec, targets low bit rate voice communication, specifically designed for digital radio applications operating within constrained bandwidths. The project focuses on achieving intelligible speech quality at data rates around 2400 bits per second, a critical parameter for efficient spectrum utilization in amateur radio. Its development addresses the need for robust voice transmission over channels where higher bit rate codecs would be impractical or inefficient. The resource details the technical specifications and implementation aspects of Codec2, including its underlying algorithms and performance characteristics. It provides insights into how the codec processes speech to achieve its low bit rate, outlining the various coding schemes and their impact on voice fidelity and error resilience. The information presented allows radio amateurs and developers to understand the codec's operational principles and its suitability for integration into custom digital communication systems. Applications for Codec2 extend to digital voice modes on HF and VHF bands, enabling more users to share limited spectrum resources. The project's open-source nature facilitates community contributions and widespread adoption, fostering innovation in digital amateur radio. It represents a significant effort to provide a freely available, high-performance speech coding solution for the amateur radio community.

Listen online to NYPD Special Operations Division live radio audio feed.

ACOM 1000 modification uses electric band switching, such that both 6m and 4m operation can be maintained.

RCKLog is a windows freeware program for logging and administration of SSB and CW-Contest with simultaneous control of transceiver and real-time operation of Packet-Radio.

Presents the Aceco product line, focusing on their range of frequency counters, RF testers, and specialized bug finders. It details the capabilities of the _FC-1000_ and _FC-2000_ series as user-friendly, affordable frequency counters operating up to 3 GHz. The resource also highlights the _FC-3002_ as a portable RF finder capable of automatically tuning _ICOM CI-V_ or AOR scanners to detected signals, emphasizing its utility in secure monitoring. Furthermore, it describes the _FC-5000_ series as a wideband FM receiver that rapidly locks onto and demodulates FM signals, outputting audio through a built-in speaker, making it suitable for counter-surveillance and radio communication testing. The page provides technical specifications and operational distinctions for each product series. The content is structured to differentiate between the core functions of frequency measurement, signal tracing, and FM signal demodulation across the various models. It clarifies that these devices are not traditional scanners but offer faster signal acquisition for specific applications. The information is presented in both English and German, with a note indicating ongoing translation efforts for the German sections. The resource serves as a product catalog and technical overview for Aceco devices, distributed by WiMo Antennen und Elektronik GmbH, providing essential details for potential buyers interested in RF measurement and surveillance tools.