Search results

Demonstrates how to construct an automatic band decoder, moving beyond manual selector switches for antenna and filter control. It addresses the challenge of varying band data outputs from different transceivers: Icom rigs provide voltage values, Yaesu rigs use Binary Coded Decimal (BCD), and Kenwood rigs lack direct band data output. The resource highlights a clever solution utilizing logging software like _CT (K1EA)_ and _DX4WIN_ to emulate Yaesu's BCD output via a PC's printer port, making the decoder compatible with any rig. The author details experiences building decoders based on designs by Bob _K6XX_ and Guy _ON4AOI_, noting K6XX's simple TTL chip design and ON4AOI's more comprehensive, opto-isolated unit capable of controlling ten outputs and bandpass filters like the _Dunestar_. It also references a _W9XT_ board design, which Steve Wilson, G3VMW, modified with BD140 transistors for source drivers, emphasizing safety. The author successfully cased an ON4AOI-based decoder in an old modem case, connecting it to an FT1000MP or a PC printer port to drive remote relays and a Dunestar Band Pass Filter.

A video demonstrating SMD board inside FT-897D to makes the two fans run only when temperature threshold is reached

Demonstrates the construction and implementation of a **two-element phased vertical array** for 40 meters, utilizing _Christman phasing_ techniques. The author, W4NFR, details the process from building individual 1/4-wave aluminum verticals to integrating them into a phased system. The resource covers antenna spacing of 32 feet, elevated radial design, and the critical steps for tuning each vertical to achieve a 1.1:1 SWR before combining them. It also provides insights into calculating precise coax lengths for feedlines and the phasing delay line, emphasizing the use of an MFJ-269 Antenna Analyzer for verification. The finished system exhibits good front-to-back nulls, with an overall SWR ranging from 1.6:1 to 2.2:1, which is managed by an antenna tuner. The project includes detailed photos of the relay box, showing 12 VDC relays capable of handling 5KV, and the control box in the shack for switching between three different antenna pattern configurations. Static bleed-off chokes are incorporated for protection, and the construction emphasizes robust weatherproofing for outdoor elements.

Juste a little demo of the Kenwood TS-570 transceiver by F5UFX

Istructions to use the IFD demodulator

A fractional bandwidth of up to 30:1 characterizes spiral antennas, making them highly effective across a very wide frequency range, often from 1 GHz to 30 GHz. The resource details two primary types: the **Log-Periodic Spiral Antenna** and the **Archimedean Spiral Antenna**, defining each with specific polar functions and illustrating their planar configurations. It explains that spiral antennas are typically circularly polarized, with a Half-Power Beamwidth (HPBW) of approximately 70-90 degrees, and a peak radiation direction perpendicular to the spiral plane. The content elaborates on critical design parameters affecting radiation, including the total length (outer radius) for lowest frequency, the flare rate ('a' constant) for optimal radiation versus capacitive behavior, the feed structure (often an infinite balun) for high-frequency operation, and the number of turns (typically 1.5 to 3 turns). It also discusses the theoretical impedance of 188 Ohms for Log-Periodic spirals, derived from Babinet's Principle, noting actual impedances are often 100-150 Ohms. The article presents a simple construction method for an Archimedean spiral, demonstrating VSWR and efficiency measurements. Measurements from a constructed spiral antenna show a VSWR that is fairly constant across the band, albeit with a mismatch loss of about 3 dB. The antenna efficiency remains around -5 dB (31.6%) across its operating range, indicating a decent wideband radiator despite opportunities for optimization.

Showcasing a specialized product line, Advanced Receiver Research presents a comprehensive catalog of **low noise preamplifiers** and microwave **Gunnplexers**. The offerings span a broad spectrum of radio frequencies, from VLF, LF, MF, and HF bands up through VHF, UHF, and microwave, catering to diverse applications including amateur radio, commercial installations, and military systems. Their product range includes mast-mount preamplifiers, inline attenuators, power dividers, and various coaxial components. My own experience with similar low-noise front ends for weak-signal work on 2 meters and 70 centimeters underscores the critical role such components play in maximizing receiver sensitivity, especially when chasing distant DX or engaging in EME. The detailed product descriptions and technical specifications provided on the site allow operators to select the optimal preamplifier for their specific band and noise figure requirements, essential for improving signal-to-noise ratio. The site also lists specialized products for unique applications like Nuclear Magnetic Resonance (NMR) and Studio Transmitter Links (STL), demonstrating a depth of engineering capability beyond typical amateur radio fare. This breadth of offerings, coupled with clear ordering and warranty information, positions Advanced Receiver Research as a key supplier for high-performance RF components.

This article compares two commercial vertical antennas for the 4-meter amateur radio band: the Watson WVB-70 half-wave and the Sirio CX4-71. The Watson measures 2.03m in length, costs around £40, and exhibited adequate performance but required additional waterproofing after rain affected its VSWR readings. The longer Sirio CX4-71 (3.02m) performed noticeably better, delivering signals approximately 2 S-points stronger than the Watson. The Sirio demonstrated high build quality, a stable 1.2-1.4:1 VSWR, and weather resilience, though minor VSWR fluctuations were observed during rain and frost. Both antennas are half-wave designs requiring no ground plane radials.

Demonstrates the adaptation and construction of a 7-element DK7ZB Yagi antenna for the 4-meter band (70 MHz), utilizing components from a defunct 2-meter CUE DEE Yagi. The resource details the modifications made to the original DK7ZB design to fit the shorter CUE DEE boom length, specifically adjusting element lengths for 6mm rod elements while reusing existing mounting holes for the reflector and last director. It provides precise element lengths for the reflector, dipole (12mm aluminum tube), and five directors, along with a note on cutting elements for transport. The article includes a 4NEC2 simulation file for performance analysis and an SWR plot, confirming the antenna's electrical characteristics. It also specifies the calculation for the quarter-wavelength matching cable using SAT752F coaxial cable, resulting in a 909mm length. Practical application is shown with the finished antenna in operation at JO20XC, listing several activated Maidenhead squares such as JO56PA and JP40KS, validating its effectiveness for portable 70 MHz operations.

Demonstrates the _SQUIRL Field Day Logger_, a specialized software tool designed for efficient contact logging during the annual ARRL Field Day event. The resource details its core functionality, which includes real-time logging to easily readable text files, with filenames structured by callsign, band, and mode (e.g., K8DAA-20M-SSB.txt). It highlights features such as a real-time history grid of previous contacts, a dynamic USA and Canada map displaying contact locations, and a duplicate checker that provides audio notifications and pre-fills class/section data for previously worked stations. The software also includes an ADIF export function, enabling users to transfer logs to other general-purpose logging programs. The software's design emphasizes simplicity and ease of use, allowing for rapid on-the-spot training, as noted by users like W4CMB. It supports various operating systems, including Windows 98 through 8, and has been successfully run on Linux via _Wine_. Key usability enhancements include a "double-size" feature for improved readability and a "Space Mode" for quick field navigation. The version history indicates continuous development from 2001 to 2013, with significant additions like the real-time Field Day Map in 2003 and ADIF export in 2004, which allows for seamless integration with other logging platforms.

Demonstrates the construction of a custom programming cable for Yaesu VX-7R and VX-5R handheld transceivers, enabling computer interfacing for memory management and frequency coverage adjustments. The resource details a six-transistor circuit design, powered by the computer's RS232 interface, utilizing readily available and inexpensive discrete components. It includes a complete bill of materials, specifying transistors like the _2N2222_ and _2N3906_, diodes, and resistors, along with a matrix board layout for compact assembly within a 75x50x25mm enclosure. The guide provides practical tips for working with matrix board, such as scoring and snapping, track cleaning, and component soldering order. It outlines the specific connection requirements for both the VX-7R (via Yaesu's CT-91 breakout lead with a 2.5mm stereo jack) and the VX-5R (via CT-44 or a four-section jack), detailing signal and ground pinouts. The author successfully tested three circuits, documenting the one with complete two-way communication, allowing users to program their rigs with software like _VX-7 Commander_ and achieve capabilities beyond commercial cables, including band adjustments.

The 10-minute, 25-second video demonstrates making a QSO via the VO-52 amateur radio satellite, focusing on real-time Doppler shift correction. It features Simon, 2E0HTS, operating a Yaesu FT-847 transceiver and a homebrew dual-band Yagi antenna, specifically a 10-element 435 MHz Yagi for uplink and an IO Loop for 145 MHz downlink. The video visually details the operator's technique for continuously adjusting the uplink frequency to compensate for the satellite's changing velocity relative to the ground station, a critical aspect of successful satellite communication. The demonstration highlights the practical application of Doppler compensation, showing the operator tuning the transmit frequency to maintain a stable received signal from the satellite. This approach contrasts with systems employing automatic Doppler correction or full-duplex operation, providing insight into manual frequency management for satellite passes. The video serves as a direct, observational guide for hams interested in LEO satellite operations, particularly those using non-tracking, manually tuned setups.

According to wikipedia a software-defined radio is a radio communication system which uses software for modulation/demodulation of signals

A spanish commercial windows PSK Software, demo version is available by EA1CUI

AM stereo receivers are available, with technical descriptions of modulation and demodulation, as well as listing of known AM stereo stations.

The X80 multi-band HF vertical antenna, a commercial iteration of the Rybakov design, exhibits a physical length of 5.5 meters, or approximately 18 feet, and is constructed from aluminum tubing. It operates as a non-resonant vertical, requiring an external antenna tuner for impedance matching across its intended operating frequencies. The antenna's design incorporates a 1:4 UNUN at its base, facilitating a nominal 50-ohm feed point impedance for the coaxial cable. Performance observations indicate effective operation on 40 meters, 20 meters, 15 meters, and 10 meters, with reduced efficiency on 80 meters and 160 meters due to its relatively short electrical length for these lower bands. Comparative analysis with a G5RV dipole and a half-wave end-fed antenna reveals the X80 offers a lower take-off angle, beneficial for DX contacts, particularly on the higher HF bands. Field tests conducted with an Icom IC-706MKIIG transceiver and an LDG AT-100ProII autotuner demonstrate the X80's ability to achieve acceptable SWR across 80m through 10m. The antenna's compact footprint and ease of deployment make it suitable for restricted spaces or portable operations, though its performance on 80 meters is noted as a compromise compared to full-size resonant antennas.

Demonstrates various practical amateur radio projects and technical discussions through video episodes. One episode details cutting and retuning a _1/4 wave shorted stub_ from 101.7 MHz to 107.5 MHz to safeguard a transmitter's driver stage, alongside insights into advanced _160-meter antenna systems_ like eight-circle arrays and beverage antennas. Another segment covers upgrading firmware on an _ATS-20+_ receiver using AverDudes for improved display and functionality, and a detailed guide on using D-Star DR mode on an _ICOM ID-52A_ for international repeater programming. Additional content includes a deep dive into _OpenHamClock_ as a potential replacement for the HamClock project, updates on _Raspberry Pi 5_ running Trixie OS, and a review of the Choyong LC90 Internet radio with AI integration. The series also features "Ham College" episodes, which meticulously prepare viewers for the Technician Exam by covering topics such as antenna and transmission line measurements, SWR interpretation, and the functions of basic electronic components like rectifiers, relays, and transistors. Practical advice on coaxial cable characteristics, dummy loads, and proper soldering techniques is also provided.

Kenwood Ibérica's online presence details their extensive product line, including the NEXEDGE NXDN and DMR digital radio systems, alongside traditional analog offerings. The site categorizes transceivers by mode, such as HF / Todo Modo (All Mode), and portable/mobile VHF/UHF units, catering to various amateur radio operating preferences. This includes specific accessories like batteries, chargers, microphones, and programming cables, essential for maintaining and customizing radio equipment. The Spanish portal also highlights Kenwood's broader electronics portfolio, extending beyond amateur radio. This encompasses car electronics, featuring navigation and multimedia systems, as well as marine receivers and speakers. The product range covers everything from CD and CD-less car receivers to power amplifiers and DashCam/RearCam solutions, demonstrating the brand's diverse market reach. Beyond communications gear, the site presents home audio systems, including all-in-one receivers and portable party speakers. This breadth of offerings underscores Kenwood's long-standing presence in both the consumer electronics and two-way radio sectors, providing a centralized resource for product information and support.

Guglielmo Marconi's foundational contributions to wireless communication began in 1894, inspired by Heinrich Hertz's discovery of radio waves in 1888. His initial experiments at his family home near Bologna quickly demonstrated signal transmission beyond line-of-sight, achieving distances up to **two miles** within a year. Marconi secured a patent in 1896, subsequently gaining interest from the British Admiralty after disinterest from the Italian government. By 1899, Marconi's system facilitated transmissions across the Bristol Channel (nine miles) and the English Channel (31 miles). A pivotal moment occurred in 1901 with the successful _transatlantic transmission_, defying the prevailing belief that Earth's curvature would limit practical range to approximately 200 miles. This achievement catalyzed the rapid development of the wireless industry. Marconi continued refining his inventions and, in 1909, shared the _Nobel Prize_ in physics with Karl Ferdinand Braun for their advancements in radio technology.

Demonstrates the operational status and reception reports for the SK6RUD/SA6RR QRPP beacons, which transmit on 478.9 kHz, 1995 kHz, 10.131 MHz, and 40.673 MHz. These beacons utilize extremely low power, with the 630-meter beacon operating at approximately 0.1 watt ERP into an L-antenna, showcasing the potential for long-distance contacts under favorable propagation conditions. The site details the specific frequencies and antenna types employed, such as a vertical at 500 kHz and a 1/4 vertical for higher bands. The resource compiles over 10,530 reception reports from amateur radio operators worldwide, logging details such as date, time, band, RST signal report, locator, distance, and receiver setup. Notable long-distance reports include a 500 kHz reception by AA1A-Dave from 5832 km in 2008 and a 10.133 MHz reception by ZL2FT-Jason from 17680 km in 2010, illustrating the global reach of these low-power transmissions. Each log entry provides specific equipment used by the reporting station, including transceivers like the Yaesu FT817, ICOM IC-7300, and various antenna configurations such as coaxial mag loops, inverted Ls, and end-fed wires. The primary objective of the SK6RUD beacons is to challenge conventional notions of power requirements for effective two-way communication, proving that contacts over significant distances are achievable with minimal output. The site also includes a submission form for new reception reports, fostering community engagement and continuous data collection on propagation phenomena across different bands. The detailed logs offer practical insights into real-world propagation characteristics and the efficacy of QRPP operations.

Crossband repeat operations on the Wouxun KG-UV8D dual band multifunctional two-way radio. This demo explains differences in the cross band repeater functions of the KG-UV8D.

This page presents a curated list of individuals who have made significant contributions across various fields while also being active amateur radio operators. For instance, Dr. Joseph H. Taylor, co-winner of the 1993 Nobel Prize in Physics for the discovery of binary pulsars, is recognized for developing the _WSPR_ and _WSJT_ weak signal mode software. Similarly, Wilson Greatbatch, inventor of the cardiac pacemaker with over **150 patents**, is featured. The resource details the diverse backgrounds of these hams, from Professor Donald H. Menzel, an astrophysicist at Harvard, to Hiram Percy Maxim, often called "The Father of Amateur Radio," who also pioneered in the automobile and aviation industries. King Hussein of Jordan, JY1, is noted for his active participation on 20 meters, engaging with fellow amateurs like Pat Kilroy, WD8LAQ. Other entries include Arthur M. Young, designer of Bell Helicopter's first model, and Marlon Brando, KE6PZH/FO5GJ, known for operating from his private island in French Polynesia. Peggy Sue Gerron-Rackham, K5PSG, gained her license after a special event station, demonstrating the hobby's broad appeal.

Call Book Log 3.0 is a web-based logging solution for amateur radio operators, designed for self-hosting on a web server with MySQL/MariaDB and PHP 7+ support. It provides a mobile-friendly interface for viewing, adding, editing, deleting, backing up, and restoring QSO logs. The software features a streamlined setup process, allowing users to quickly deploy a personal logging system accessible via any web browser. Key functionalities include displaying the last **5** contact dates for previously worked stations, enhancing log management by providing immediate historical context during QSO entry. The system also includes a central administrative section for authenticated users to manage log entries. The 3.0 version represents a significant code overhaul, focusing on improved performance and a more *visually appealing* user experience compared to earlier iterations. Enhancements include better pagination, a redesigned menu with icons, and color-changing rows for improved readability. The add log page now incorporates a one-click time update feature, addressing user feedback regarding time synchronization during rapid QSO entry. This iteration builds upon previous versions like 2.1, which corrected an automatic _UTC date_ bug, and 2.0, which featured a full rewrite to resolve browser quirks and optimize search functions. The software's evolution demonstrates a commitment to functional stability and user interface refinement.

KE7FTE, N7QQU and W9ERT show us the "drag and drop" flexibility of the Icom D-STAR System.

The early 20th century saw significant advancements in wireless communication, culminating in the first successful transatlantic radio signal. This historical account details Guglielmo Marconi's pioneering efforts, from his initial experiments with electromagnetic waves to his patented wireless system in 1900. It describes the technical challenges of long-distance radio transmission, particularly the prevailing belief that radio waves would be lost due to the Earth's curvature over vast distances. On December 12, 1901, Marconi established a receiving station in Newfoundland, Canada, utilizing a _coherer_ and balloons to elevate the antenna. Signals, consisting of the Morse code letter "S" (pip-pip-pip), were transmitted from Poldhu, Cornwall, England. The successful reception of these faint but distinct signals across **1,700 miles** confirmed Marconi's theories, marking an epoch in communication history. This achievement demonstrated the viability of global wireless communication, paving the way for future developments in radio technology.

Demonstrates the capabilities of CW_Shark, a dedicated 32-bit Windows application for Morse code operations. This software facilitates the analysis, decoding, and encoding of CW signals, providing hams with a versatile tool for various aspects of amateur radio communication. It supports four distinct modes: Decode Only, Keyboard QSO, Straight or Paddle Key QSO, and Straight or Paddle Key Practice, catering to different user needs from passive listening to active keying. Operators can utilize the Decode Only mode for signal analysis, while the Keyboard QSO mode allows for text-based interaction. The Straight or Paddle Key QSO mode offers a direct interface for traditional keying, enabling real-time communication. For skill development, the Straight or Paddle Key Practice mode provides a structured environment to hone Morse code proficiency. CW_Shark integrates essential functions for CW enthusiasts, supporting both learning and active participation in Morse code exchanges. Its focused design aims to assist operators in mastering and enjoying the art of _CW communication_.

Operating magnetic loop antennas requires careful consideration of RF safety, particularly regarding near-field magnetic field intensity. This resource presents calculations for magnetic field strength (H-field) at various distances from a magnetic loop, emphasizing that the H-field is significantly higher than the E-field in the near-field region due to the inductive nature of the radiating element. It provides specific formulas and examples for determining safe operating distances based on power levels and loop dimensions, crucial for compliance with RF exposure limits. The analysis compares calculated H-field values against FCC and ICNIRP maximum permissible exposure (MPE) limits for controlled and uncontrolled environments. It demonstrates that even at QRP power levels (e.g., 5W), the H-field can exceed MPE limits within a few feet of the antenna, necessitating greater separation distances than often assumed for electric field considerations. The practical application of these calculations helps amateur radio operators configure their stations to ensure personnel safety and regulatory compliance when deploying compact, high-Q magnetic loop antennas.

The K-Com website, originally intended for RFI rejection products, currently hosts content for a Nigerian football betting platform. The site promotes wagering on live EPL, NPFL, and UCL matches, offering competitive odds and instant OPay and bank payouts. It highlights features such as a **99 sign-up bonus** for new players, daily deposit rewards, and VIP cashback, alongside a mobile-friendly interface and NLRC licensing. The platform provides a demo hall with _1,000,000 demo credits_ for guest players to test strategies without registration. It emphasizes secure and reliable gameplay, instant withdrawals, and multi-game access, claiming over 100,000 active players. The content includes user testimonials and an FAQ section addressing game access, registration, promotions, and mobile compatibility, but contains no information related to amateur radio or RFI filters.

For over 20 years, bhi Ltd has specialized in digital signal processing (DSP) technology to mitigate noise and interference across various radio channels. Their product line, including the _ParaPro EQ20 Audio DSP_ units, focuses on enhancing receive audio quality, even for operators without significant noise issues, by offering precise parametric equalization to suit individual hearing preferences. The core offerings are noise-cancelling speakers and in-line modules, specifically engineered for amateur radio applications, but also adapted for commercial, PMR, and marine radio systems. The company provides audio demonstrations, such as a 20m SSB example and a 14MHz band filter comparison, allowing users to hear the effectiveness of their DSP units against common QRM sources like plasma TV interference or diesel engine noise. Located in Burgess Hill, West Sussex, UK, bhi Ltd emphasizes clear voice communications, aiming to remove unwanted noise and leave only intelligible speech.

Demonstrating tuning and operation of the ameritron al-811h in this Youtube video

For radio amateurs and electronics enthusiasts requiring specialized wiring solutions, Multi/Cable Corporation provides custom multi-conductor cable manufacturing services. They focus on made-to-order constructions, offering a broad range of specialty cable products including composite, instrumentation, electronic, flexible cord, thermocouple, high-temperature, and Mil-Spec wire and cable. Their capabilities extend to extensive customization of all cable components, ensuring precise adaptation to specific application requirements, which can be critical for bespoke shack setups or antenna control lines. With over 50 years in business, Multi/Cable emphasizes low minimum orders, quick turnarounds, and competitive pricing, making custom cable solutions accessible even for smaller projects. A case study highlights their role in helping an emergency vehicle lighting company expand offerings by providing versatile and cost-effective wire bundles, demonstrating their ability to support diverse technical needs beyond typical off-the-shelf options. They also provide reference data and guides on choosing conductors, insulation, and jacketing materials.

Conductor is a training tracking software that can organize any type of education, training, certification or license. It generates a multitude of reports perfect for regualtory bodies, free demo.

HB9BZA's LoTW users list, originally compiled since 2005 from DX-Cluster and user submissions, now primarily leverages the official ARRL full users list released on July 29th, 2017. This resource details 228,012 calls across 340 current DXCC entities, with the latest update noted on March 2, 2026. It offers various formats, including a full list, text versions, and breakdowns by country, providing valuable insights into LoTW participation for DXers. While the ARRL's official list with "last upload" dates diminished the original list's unique utility, HB9BZA's site continues to offer statistics and user counts by country, which remain of interest. The author, HB9BZA, expresses gratitude to contributors who helped maintain the list's accuracy over many years, achieving an impressive 96.4% match with the ARRL's data before the official release. Knowing which stations are LoTW active encourages more hams to join the system, demonstrating that even rare DXCC entities like Ducie Island or Heard Island can be confirmed quickly. For instance, HB9BZA recounts a 36-minute QSL confirmation for a 3A2MW contact. The list also integrates with the RXCLUS packet radio/telnet client, enhancing DXCC award tracking by identifying LoTW participants and utilizing upload dates for alarms.

GAL-ANA is an Antenna-Analyzing Tool software, based on NEC2/MININEC3m engines currently available in demo mode for download

Demonstrates a range of specialized radio frequency equipment and consulting services for amateur and professional applications. The offerings include _Vector-Finder_ direction finding antennas, various test equipment such as _gate dip meters_ and RF sniffers, and communications receiving adjuncts. Additionally, the company produces satellite antennas for weather satellite reception, voice amplification devices like the _Flex-Mike_, and custom prototype circuit boards. The company's product line addresses needs for precise RF measurement, signal detection, and specialized antenna systems, particularly for direction finding and satellite communications. Their historical association with National Radio (HRO) suggests a legacy in radio technology. The site also highlights a subsidiary, Sierra Mountain Products, which offers outdoor recreational gear, indicating a diversification beyond core RF manufacturing.

This test circuit is easy to duplicate, and demonstrates the extreme voltages that appear in an amplifier when the load is improper for the amount of drive power applied.

Demonstrating the construction of a short dipole antenna tailored for the 60 meter band, this resource provides detailed instructions for radio enthusiasts with limited space. The design incorporates inductive loading using two inductors (L1/L2) made from PVC tubes, allowing for effective operation on 5 MHz. The antenna consists of 12 meters of wire, divided into four sections, with specific dimensions and materials outlined for optimal performance. Results from users indicate that this antenna can significantly enhance DXing capabilities on the 60 meter band. Feedback from operators suggests that while the design is effective, adjustments may be necessary based on individual setups, such as coil diameter and wire gauge. Many users report successful construction and operation, with some experimenting with variations to improve resonance. The practical application of this antenna design has led to successful contacts and improved signal quality, making it a popular choice among 60 meter band operators.

The Nederlandse Vereniging voor Radio Amateurs (NVRA) operates from Haarlem, Netherlands, under the club callsign PI4HLM and maintains an ATV repeater, PI6HLM. The organization's website provides updates on internal governance, such as the postponement of a General Members Meeting due to necessary amendments to its 1986 statutes. These amendments are required to comply with the Wet Bestuur en Toezicht Rechtspersonen (WBTR) — Dutch legislation concerning the governance and supervision of legal entities. The NVRA's operational focus includes local amateur radio activities, indicated by its Haarlem location and the presence of a **PI6HLM** ATV repeater. The club's adherence to national legal frameworks for non-profit organizations, specifically the **WBTR**, demonstrates its structured approach to club management and long-term viability within the Dutch amateur radio community.

Observing extremely slow CW (QRSS) signals requires specialized reception and display techniques, often involving long-term signal integration to make faint traces visible. This resource compiles numerous screenshots from active QRSS grabbers globally, providing a visual record of signal propagation and operational activity on specific amateur bands. Each entry typically includes the callsign of the grabber station, its grid square, and often the band being monitored, such as 40 meters or 30 meters. The compendium presents a diverse array of grabber outputs, with examples from North America, Asia-Pacific, and Europe. Notable stations featured include _W5GB_ at New Mexico State University, _VE1VDM_ in Canada, and _I2NDT_ (the author's own grabber). The collection illustrates the unique visual signatures of QRSS transmissions, where signals appear as faint lines or patterns against a noise floor, often over extended periods. The utility of such a collection lies in its ability to demonstrate real-world QRSS signal characteristics and the geographical distribution of active grabber sites. It serves as a historical snapshot of QRSS activity, allowing operators to compare signal traces and observe propagation phenomena across different continents.

Demonstrates a specialized **DX cluster** designed to support the annual Jamboree On The Air (JOTA) event, facilitating real-time spotting for participating Scout stations. While its web interface has been discontinued due to security concerns, the cluster remains fully operational and accessible through standard cluster software. Operators can connect to the JOTA cluster by pointing their client to www.pi4raz.nl on port 7300. This setup allows for the exchange of **DX spots** and other operational information relevant to JOTA participants, ensuring that Scouts and their amateur radio mentors can continue to make contacts and log stations during the event.

Frequencies and location of every meteo radiosonde launching centres in Europe. Equipments, antennas, history, SondeMonitor and BalloonTrack tutorials

The Icom AH-4 autotuner operates efficiently across multiple HF bands, providing seamless automatic tuning for antennas from 3.5 MHz to 54 MHz. Its robust design allows for outdoor installation, making it suitable for field operations and fixed stations. The unit interfaces with Icom transceivers via a control cable, enabling automatic band switching and tuning. The AH-4 is capable of handling up to 120 watts of RF power, ensuring compatibility with most amateur radio setups. Its weather-resistant casing and compact form factor make it a versatile choice for operators requiring reliable performance in diverse environments. Field tests demonstrate the AH-4's ability to maintain low SWR across its operational range, enhancing signal quality and transmission efficiency. Compared to manual tuners, the AH-4 offers significant time savings and ease of use, particularly in rapidly changing band conditions. Its integration with Icom radios simplifies operation, eliminating the need for manual adjustments. The autotuner's performance is consistent with other high-end models, providing a cost-effective solution for amateur operators seeking dependable tuning capabilities without sacrificing performance.

Constructing a high-power 70cm solid-state amplifier presents unique challenges, particularly when aiming for 500 watts output using modern LDMOS devices. This resource details the author's experience building a 70cm amplifier based on a _Freescale MRFE6VP5600H_ transistor, initially from an RFHAM kit. It meticulously outlines the necessary modifications to achieve advertised performance, including optimizing input and output matching, correcting bias circuitry, and ensuring proper output balun connections for stability. The author shares specific adjustments, such as trimming the prototyping board for better transistor fit, drilling additional mounting holes for improved heat sinking, and replacing original matching capacitors with a single _20pf MIN02 metal mica_ for superior output. A critical fix involved jumpering gate decoupling pads to balance the push-pull transistor halves, which increased output to 580W and improved IMD. The resource also highlights a crucial correction to the output balun connection, initially reversed in the _Dubus_ article schematic, which resolved intermittent stability issues. Test results are provided, showing input power, output power, and drain current at 50V, demonstrating the amplifier's performance after modifications. This practical account offers valuable insights for hams undertaking similar high-power UHF amplifier projects, especially those working with LDMOS devices and kit-based constructions.

Ea2id demonstration video of the Ameritron AL-811H in spanish

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.

Details the construction of an **HF converter** designed by M1GEO, George Smart, specifically to extend the frequency range of the FunCube Dongle Pro (FCD) for amateur radio reception. The FCD natively covers 64 to 1,700 MHz, but this project enables reception from 0 Hz to 64 MHz by up-converting signals to the FCD's operational range. It employs a **double-balanced mixer** with a 100 MHz local oscillator (LO) to translate incoming HF signals; for instance, a 1 MHz signal appears at 101 MHz within the FCD's passband. The design incorporates a 7th-order Chebyshev low-pass filter with a 62 MHz cutoff frequency at the input to mitigate image frequencies, ensuring cleaner spectral presentation. George provides the schematic, PCB masks, and Gerber files for replication, noting that Far Circuits also offers PCBs. The resource includes test results for the low-pass filter and measurements of LO leakage, identifying -36.8 dBm at 100 MHz as a potential sensitivity concern. M1GEO discusses potential improvements, such as adjusting the mixer's LO drive, adding a balance pot, or incorporating a post-mixer high-pass filter to reduce LO breakthrough. Audio recordings from 40m and 17m demonstrate the converter's performance with WRplus SDR software.

Learn quadrature modulation through interactive flash programs. These programs will allow you to learn about quadrature modulation and quadrature demodulation without getting overwhelmed by math.

Approximately 2.8% annual decline in Australian amateur radio licenses was observed over the five years leading up to 2002, a trend that prompted further analysis of the country's amateur population. This resource examines licensing statistics and demographic shifts within the Australian amateur radio community between 1998 and 2007, utilizing available data to identify patterns in license issuance and renewal. The study focuses on **population trends** and the underlying factors contributing to changes in the number of active **amateur radio operators**. It provides insights into the health and growth trajectory of the hobby in Australia during this specific period. Understanding these demographic shifts is crucial for clubs, regulatory bodies, and equipment manufacturers to adapt strategies and foster engagement.

This site is devoted to promoting RSQ as an improved signal reporting system for narrow band digital modes and to demonstrating its application to the popular PSK31 mode.