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Online shop for obsolete electronic components, tubes and semi-conductors

Reports indicate the PA1RBZ DX Cluster, previously accessible via telnet at pa1rbz.dyndns.org on port 9000, is no longer operational. The QSL.net hosting platform displays a 404 error, indicating the specific page or file for the cluster's web interface or related information is missing. This service was designed to provide amateur radio operators with real-time DX spotting data, facilitating long-distance contacts across various bands. The cluster's primary function was to aggregate and disseminate DX spots, allowing users to monitor current propagation conditions and identify active stations. Such systems are crucial tools for DXers and contesters, enabling rapid response to new openings and rare DX entities. QSL.net, which hosts over 30,000 amateur radio websites, provides these services free of charge to hams, relying on user donations for operational continuity.

This resource compiles claimed scores, often referred to as "rumor scores," for numerous amateur radio contests, providing a historical snapshot of competitive activity from 1993 through 2007. It lists entries for prominent events such as _CQWW CW_, _ARRL Sweepstakes_, _IOTA Contest_, and various _NAQP_ events, categorized by year and contest. Each entry typically includes the contest name and the month/year of operation, allowing users to quickly navigate to specific contest periods. The site also references the _3830 Web Page_ on Contesting.com as the primary submission portal for these claimed scores. The collection offers a unique perspective on contest participation and performance trends over more than a decade, preceding the widespread adoption of real-time score reporting systems. While not official results, these rumor scores provided early indications of top performers and overall activity levels for a wide array of HF and some VHF contests, including _ARRL 10M_ and _CQWW VHF_. The historical data can be useful for analyzing past contest popularity, identifying consistently strong operators, or simply reminiscing about earlier competitive eras in amateur radio.

Solving interference from television channel 11 on 144MHz transverters by Chris Cox, NØUK, G4JEC

Thanks to the popularity of cell phones, laptops and other personal electronic devices, the battery industry has been market-driven to produce higher capacity batteries in lighter weights than previously possible with yesterday's chemistries.As a result, a wide variety of battery types are available to the outdoor QRP operator.

Our purpose is to have fun with Amateur Radio, to help others that wish to join the hobby, and to offer assistance to our community in times of eminent danger or disaster.

The K9IU Indiana University amateur radio club provides a robust station environment for its members, located within the Indiana Memorial Union. This setup includes a variety of radio resources, making it accessible for students and faculty interested in two-way radio communication, from local ragchews to international DXing. The club's facilities are available for use at any time, fostering an active amateur radio community on campus. Members can engage in various aspects of the hobby, utilizing the club's equipment for operating on different bands and modes. This hands-on access supports learning and practical experience in radio theory and operation, which is crucial for new hams and seasoned operators alike. The K9IU club serves as a central point for amateur radio activities at Indiana University Bloomington, aligning with the university's broader academic and extracurricular offerings.

Devoted to disseminating information about Atwater Kent Radios and the man who created them.

The California QSO Party (CQP) is the premier state QSO party held every year on the first weekend of October. The Northern California Contest Club (NCCC) has sponsored CQP since 1974.

Explains the proper formatting of international addresses on postal items, a critical aspect for ensuring successful delivery of QSL cards. It details how the country of origin dictates the destination country's name format, while the destination country's postal authority governs the remainder of the address. The resource highlights _Universal Postal Union_ (UPU) regulations, specifically Article RL 123.3.3, which mandates the use of roman letters and Arabic numerals for clarity. It provides practical examples, such as an item from Great Britain to the United Arab Emirates, illustrating the need for dual-language addressing. The guide also clarifies the separation of elements for proper transmission versus local delivery, ensuring that the destination country name is clearly marked in capital letters and preferably in an internationally recognized language to facilitate transit, preventing misdirection and ensuring a **99%** delivery rate for QSLs.

On March 27, 2017, the FCC adopted final rules for the USA 630-meter band, detailed in Report and Order FCC 17-33, which required PLC coordination with the Utilities Telecom Council before amateur operations could commence. This resource documents the WD2XSH experimental group's activities, including authorized stations, band plans, and frequency assignments within the 465-515 KHz range, with many stations operating between 495-499 KHz and 501-510 KHz. The site also highlights the WRC-12 decision on February 14, 2012, which granted a new **7-kilohertz-wide** secondary allocation between _472-479 kHz_ for the Amateur Radio Service worldwide. The group's efforts included operating with a maximum ERP of **20 Watts** across 45 stations in the continental USA, Alaska, and Hawaii, using emission modes such as CW, PSK-31, FSK-31, and MSK-31. The site provides links to download FCC 17-33 in PDF and DOCx formats, and offers a station location map, a list of stations by callsign and frequency, and an archive of news updates. Reception reports for any 600-meter station are encouraged to help the amateur radio community understand propagation and repeatability on this challenging band.

Examines Radio Frequency Systems (RFS), a manufacturer specializing in high-performance cable solutions for diverse communication infrastructures. The company, with over 120 years of heritage, focuses on designing and producing robust, long-life connectivity systems, including _low loss foam dielectric RF cable_ and _premium radiating cable_. RFS's product range supports critical applications in cellular networks, microwave antenna systems, and specialized installations within buildings and tunnels. The resource highlights RFS's commitment to innovation, addressing emerging industry standards like _FRMCS_ for railway communication and advanced fiber solutions for data centers. It also details the company's manufacturing capabilities in Hannover, Germany, emphasizing the quality and reliability associated with _Made in Germany_ products. The content covers various connectivity landscapes, from urban solutions for connected cities to private 5G credentials and future plans. Specific product categories include _fiber, power & hybrid cable_, and _low loss high power air dielectric RF cable_, showcasing their broad portfolio for complex RF environments.

ICNIRPcalc allows you to calculate safety distances for many know amateur radio antennas with respect to ICNIRP limits by DL9KCE

The Malaysian Amateur Radio Transmitters' Society (MARTS) serves as the national representative body for amateur radio operators across Malaysia, having been established in 1952. This organization plays a crucial role in advocating for the interests of Malaysian hams, fostering community engagement, and supporting the growth of the amateur radio service within the country. MARTS actively participates in national and international amateur radio affairs, often collaborating with organizations like the _International Amateur Radio Union_ (IARU) to ensure the continued development and recognition of amateur radio. The society's activities encompass a range of services for its members, including the dissemination of information regarding licensing, operating procedures, and technical advancements. MARTS also facilitates various on-air events and provides resources to help members improve their operating skills and expand their knowledge base. The organization's long-standing presence since 1952 underscores its commitment to the amateur radio community in Malaysia. MARTS supports local clubs and individual operators, promoting best practices in radio communication and emergency preparedness.

House of Batteries is a master distributor and custom battery pack assembler for every major battery manufacturer in every battery chemistry for every electronic application

An overview of the development of the Morse key for sending the Morse Code, from the first camelback keys, through straight keys and sideswiper keys to the semi automatic keyers including the Vibroplex to the modern electronic keyer.

Documentary and seminar videos for and about Amateur Radio, on DVD and online. Some make excellent club meeting programs.

This resource provides a discussion group platform for amateur radio operators interested in APRS within Argentina. It facilitates technical discussions, sharing of operational experiences, and coordination among users of the Automatic Packet Reporting System in the region. The group serves as a central point for exchanging information on local digipeater networks, IGate deployments, and mobile tracking applications, covering both hardware and software aspects relevant to APRS implementation. The forum enables members to post questions, offer solutions, and disseminate news related to APRS activities specific to Argentina, fostering a community-driven approach to problem-solving and knowledge transfer. It supports the collaborative development and maintenance of the APRS infrastructure, allowing for real-time interaction on topics such as frequency usage, network topology, and integration with other amateur radio services.

Article appeared on 73 amateur radio today in 1999 on how to unlock the secrets of sending precise Morse Code. Article contains hints on how use the stright key and the sideswiper key, but even the electronic keyers or the semiautomatic keys.

The Kitchener Waterloo Amateur Radio Club (KWARC) website provides a central hub for its members and the broader amateur radio community, detailing club activities, meeting schedules, and special events. It features a monthly newsletter, the _Kilowatter_, which archives club news and technical articles, offering insights into local amateur radio operations and projects. The site also includes information on the club's repeaters, operating on various bands, and details about the annual _Central Ontario Hamfest_. Content covers diverse aspects of the hobby, from general interest articles to specific technical discussions. The resource serves as a primary communication channel for KWARC, facilitating member engagement and disseminating information about club-sponsored activities like field days and public service events. It also lists contact information for club executives and provides resources for new licensees.

Maintaining vintage Eddystone receivers often presents unique challenges, as detailed by Victor Jenkins in his refurbishment of an EA12, where his deep understanding of RF circuits ensures optimal performance for daily shortwave listening. Similarly, Gerry O’Hara VE7GUH, a prolific contributor to the EUG website and a trustee, meticulously documented his restoration of an Eddystone S830/2, even addressing an unusual instability issue with a follow-up postscript article and YouTube videos demonstrating the fix. His work, along with numerous other articles on the "Restorations" page, showcases a master's approach to bringing vintage sets back to factory specifications or better. Beyond technical restorations, the EUG also shares compelling historical narratives. One such story recounts the discovery of a long-lost 78rpm recording featuring Eddystone Radio Ltd.'s founder, George Stratton Laughton, and other key figures discussing the company's wartime and post-war contributions to shortwave communications. This six-minute BBC production, transcribed into an MP3 file by Peter Carney, offers a rare auditory glimpse into the company's legacy, highlighting its role in supplying equipment to police, ministries, and expatriate British workers. The community aspect thrives through shared experiences, like Roger Trickett's anecdote about his Eddystone EC10, which has been continuously powered for 50 of its 54 years, traveling across continents and enduring various modifications. Another intriguing account from Roy GM4VKI details the "S640 Identity Crisis," where a seemingly standard S640 receiver turned out to be a masterfully engineered 80/20-meter SSB transceiver built into the original chassis by GI3ZX, showcasing incredible ingenuity from a bygone era of amateur radio.

Dealer for Russian Tubes, components and other semiconductors

Martek Power designs and manufactures a wide of high performance power supplies for various industries. Power supplies AC-DC, DC-AC inverters, DC-DC, EMI Filters

All the essentials about the Dip Meter or Grid Dip Oscillator used for many RF measurements including detecting resonance, locating RF emissions, and making many RF measurements.

Tips and tricks for succesful soldering. An illustrated guide for beguinners and an usefull reminder for expert in soldering.

Electronic components and parts supplier: semiconductors, capacitors, diodes, transistors, resistors, and more since 2005

The I2YSB DXpedition Team presents a collection of videos documenting their past DXpedition activities. These visual records offer insights into the operational aspects, equipment deployed, and environmental conditions encountered during various DXpedition events. The resource also contains a specific announcement regarding the cancellation of the planned Ghana AF-084 DXpedition, originally scheduled for April. It further details the refund process for sponsors who had contributed donations for the cancelled operation. The content serves as an archive of DXpedition experiences, showcasing the efforts involved in activating rare or challenging entities. It provides a historical perspective on the team's operations and logistical considerations. The site also functions as a communication channel for important updates concerning future or cancelled DXpedition plans, directly addressing the amateur radio community interested in their activities.

Operating in the **microwave** spectrum, Response Microwave, Inc. specializes in the design and manufacturing of RF and microwave signal processing components and subsystems. The company's product line encompasses a wide array of offerings, including Connectivity Series components, rotary joints, phase shifters, cable assemblies, surge protectors, terminations, Hybridline/Couperline products, circulators/isolators, directional couplers, quadrature hybrids, attenuators, custom assemblies, filters/diplexers, DC blocks & bias tees, power dividers/combiners, laser diodes & drivers, high-frequency connectors, and precision test accessories. This extensive catalog supports various applications requiring precise signal manipulation and transmission at elevated frequencies. The resource provides access to a comprehensive product catalog and a dedicated connector catalog, detailing specifications for components like **high-frequency connectors** and test cables. While specific performance data or comparative analyses are not directly presented on the main page, the breadth of products indicates a focus on providing foundational building blocks for microwave systems. The company emphasizes customer service and aims to be a reliable source for RF/Microwave/Optics product requirements, serving a growing customer base with its specialized component offerings.

A complete list of resources for the Kenwood TS-850 mantained by TK5EP

Official page of the IARU High Speed Telegraphy Championships

Since 1946, VK6 Weekly News has delivered weekly broadcasts to amateur radio operators across Australia, particularly in the VK6 region. The broadcasts include news updates, acknowledgments of contributors, and calls for operators to engage by transmitting news or submitting stories. This initiative strengthens community ties among amateur radio enthusiasts and encourages collaboration in maintaining the network of repeaters. The broadcasts reach various states, including Western Australia, Queensland, and New South Wales, ensuring that information is disseminated widely. VK6 Weekly News emphasizes the importance of operator contributions, thanking them for their efforts in sustaining the amateur radio community. Accessible through multiple platforms, it supports ongoing amateur radio activities and development in the region. Operators are invited to participate actively, enhancing the richness of the news content and fostering a collaborative spirit within the amateur radio community.

A resource page for Kendoowd TS-850 HF transceiver

Delta Electronics Manufacturing, a global manufacturer, specializes in _RF connectors_, adapters, and cable assemblies, providing custom interconnect solutions with superior performance. Their Advanced Vertically Integrated (AVI) global facilities emphasize efficiency, quality, flexibility, and cost control across their product lines. The company serves diverse industries, including broadcast and audio, test and measurement, military, aerospace, and public safety communications. For instance, Delta supplies RF interfaces for military aircraft, satellite launch vehicles, and missiles, maintaining a long-standing QPL supplier status. Their field-tested RF interconnects are also crucial for two-way radios, base station equipment, and antenna systems in public safety applications, ensuring reliable performance in critical communication infrastructure. Delta's solutions extend to commercial aircraft and semiconductor manufacturing, where their RF interconnects power etch equipment, deposition equipment, and chip testing systems worldwide.

Custom EMI Filters, AC DC Three phase filters by Filter Concepts Inc.

Product specialist for semiconductors and electron tubes based in Belgium

The premier flea market for radio, electronics, Computer & communications equipment in Indianapolis

Article on radio frequency interferences, with a long list of common RFI cause, like Plasma TV, Solar panels inverters, fluorescent tube lamps.

The San Bernardino Microwave Society, operating under the callsign _W6IFE_, serves as a significant technical hub for amateur radio operators specializing in frequencies above 1 GHz. This organization's influence extends across Southern California, providing a centralized resource for advanced RF experimentation and **regional frequency management** within the microwave spectrum. Its permanent value lies in its extensive archive of technical papers and project documentation, which are critical for operators engaged in high-frequency design and deployment. The society's infrastructure is primarily intellectual, focusing on the dissemination of specialized knowledge rather than a conventional repeater network. It offers a robust collection of technical papers from prominent members like K6PIP, K6BLG, and WA6EXV, covering topics such as Rubidium oscillator data, logging software, and filter design. This resource facilitates advanced amateur radio operations, including participation in microwave contests and the development of custom transverters for bands like 24 GHz. The site also details various member projects, such as the Owens Valley Radio Observatory Project, showcasing practical applications of **RF propagation analysis** and system integration. DXZone Focus: Microwave | Technical Papers | RF Propagation | Contest Results

The World Radiosport Team Championship (WRTC) is a unique on-site ham radio competition, typically held every four years, bringing together top operators globally. Unlike traditional contests where participants operate from their home QTH, WRTC competitors travel to a designated location and operate from identical stations under field conditions, ensuring a level playing field. Past events have taken place in diverse locations such as Seattle (1990), Slovenia (2000), Russia (2010), and Italy (2023), showcasing the international scope of this **radiosport** challenge. Because each WRTC event is organized by a dedicated, volunteer-driven committee, historical information and results often become dispersed across various online platforms. This resource serves as a centralized repository, diligently collecting and preserving data from all previous WRTC competitions. It provides a consistent point of reference for participants, enthusiasts, and researchers interested in the history and evolution of this premier **DX contesting** event. The WRTC Sanctioning Committee officially endorses this site, ensuring its accuracy and completeness.

Presents the official results for the _CQ World Wide 160-Meter Contest_, a premier event for Top Band enthusiasts. The resource details final scores for both CW and SSB segments, offering links to comprehensive articles, plaque winner lists, and club score breakdowns. It also includes access to score databases for individual modes and years, along with "Soapbox/QRM Comments" from participants, providing insights into operating conditions and experiences. This archive spans results from 2010 through 2025, with a forward-looking note regarding the 2026 SSB contest date adjustment due to a conflict with the _ARRL DX CW Contest_. The site provides specific links for each year, allowing operators to review detailed outcomes, including top scores, errata, and all-time records, such as the _SX5R_ 2017 SSB performance. The structured presentation facilitates easy navigation through historical contest data.

Togo DXpedition 5V7TT 10th-23rd October 2010

The Buddistick antenna, as demonstrated by KP4MD, effectively handles up to **250 watts** and provides coverage from 40 through 10 meters, with an optional coil extending operation to 80 and 60 meters. KP4MD's video presentation meticulously describes the antenna setup, emphasizing the critical role of the _shunting coil_ for achieving resonance on lower bands like 40 and 80 meters. This practical approach highlights how a compact antenna can deliver solid performance from a constrained location. SWR curve diagrams are included, clearly illustrating the impact of the shunting coil on the antenna's resonating frequency. These visual aids provide concrete evidence of the adjustments needed for optimal operation across different bands, particularly when space is at a premium. KP4MD's insights are particularly valuable for hams operating from apartments or other limited spaces, showcasing real-world results from a balcony installation.

Datasheet Locator is a free tool that enables you to locate product datasheets from hundreds of electronic component and semiconductors manufacturers

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

Thsi article describes a microcontroller driven semi-automatic antenna tuner capable of handling power levels up to 150 watts. The device is a low pass filter tuner manually tuned by setting the optimized L/C combination by hand and then storing the values into the EEPROM of the mictrocontroller to recall them later (seperately for each band from 80 to 10 meters including WARC bands)

A further study of the spurious emissions from an FT847 on 70 MHz by G7CNF

DC filters from radius power are specifically optimized for applications with DC supply like e.g. photovoltaic inverters. Radius Power provides total power solutions, EMI filters solutions from design to manufacturing, Three Phase, Single Phase, Power Line, IEC inlet, Power entry modules Filters.

Constructing a dual-band antenna for 40 and 20 meters often involves compromises in size or complexity. This resource presents a compact _open sleeve dipole_ design that addresses these challenges by using 450-ohm ladder line and folded elements to achieve a total length of approximately **17.17 meters**, significantly shorter than a full-size 40-meter dipole. The design leverages electromagnetic coupling, where a primary radiator handles the 40-meter band, and a second conductor resonates on 20 meters without direct electrical connection. This configuration eliminates the need for traditional traps, loading coils, or switching components, simplifying construction and reducing potential loss points. The antenna is fed with RG-58C/U coaxial cable, and a common-mode choke is recommended at the feed point to suppress sheath currents, ensuring a cleaner radiation pattern and minimizing RF in the shack. The design is well-suited for portable operations, field deployments, temporary installations, and restricted urban environments where space is a premium, offering solid performance on both HF bands.

OEMSEMI is an independent distributor for electronic components, offering worldwide spot components supply service and solutions to obsolete components supply.

Liberia 2011 5M2TT DX Pedition Official web site