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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.

BaseStation is a Windows application written originally for the SBS-1 family of Virtual Radar Receivers.

Heathkit signal generator with original paper manual for download

With over 20 years of experience, Proyecto 4 operates as a specialized ham radio retailer in Madrid, Spain, providing a diverse inventory of transceivers, antennas, and related accessories. The store features popular models like the _ICOM IC-705_ and _ICOM IC-7300MK2_, alongside Yaesu transceivers such as the _FTX-1 Optima_, which delivers 100W on HF and 50W on V/UHF bands. The product range includes mobile and portable antennas, such as the D-Original DX-NR770HB, offering 3 dB gain on 144 MHz and 5.5 dB on 430 MHz, and the Diamond RH-770 with a BNC connector. CB radio enthusiasts can find the Anytone CB SMART II AM/FM transceptor and the Telecom LS145 mobile antenna, rated for 500W and 4 dB gain on 26-30 MHz. Proyecto 4 emphasizes its in-house technical service, inviting customers to visit their laboratory for repairs and technical consultations via sergio@proyecto4.com. The store also highlights customer reviews and offers promotions like Yaesu Cashback, providing savings up to 100€.

Original article published on February 1992 on 73 Amateur Radio Today about the 2m and 70 cm copper cactus J-pole antenna

Scans of original G2DAF articles on his HF linear amplifier using QY3-125 tube

Based on original G2BCX design this J-Pole antenna for the six meter band is made with a homemade ribbon cable. The antenna shown in this article includes a coaxial cable choke feed to remove RF currents from flowing on the outer of the cable.

The Voice of America (VOA) website serves as a primary digital platform for its international news and information services, broadcasting in 44 languages. The resource presents a wide array of current events, geopolitical analyses, and cultural reports, reflecting a global perspective on news originating from the United States. Content spans various regions, including Africa, Asia, the Middle East, and specific country-focused reports from VOA's language services, such as VOA Uzbek, VOA Kurdish, and VOA Russian. The site features top stories, special reports, and sections like "All About America" and "VOA Explains," providing in-depth context on US-related topics and global issues. The VOA platform offers a continuous stream of updated news articles, covering political developments like government shutdowns, diplomatic relations, and international conflicts, alongside social and economic issues. It also includes sections for "Worth Watching" videos and "From VOA's Language Services," highlighting the breadth of its multimedia output. The content is designed to inform a worldwide audience, often presenting multiple perspectives on complex international events and US foreign policy, making it a significant reference for those monitoring global news and shortwave broadcast content.

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.

British based CW club, originally founded in 1938

Calculate EH Antenna, 20m 40 80m. Fotos, Original eh antenna building.

The Russian Internet Callbook, hosted at krasnodar.online.ru, offers a specialized lookup service for amateur radio callsigns within the Russian Federation. This online tool is designed to assist DXers and contesters in identifying contact information for Russian stations. The resource functions as a digital callbook, allowing users to search for specific callsigns and retrieve associated data, which is crucial for QSLing and verifying contacts. While the concept is to provide a comprehensive database for Russian amateur radio operators, the current status indicates a configuration issue, as the domain krasnodar.online.ru points to the server but the site itself is not configured. This suggests the service may be inactive or undergoing maintenance, impacting its utility for callsign lookups. The original intent was to serve as a key _DX resource_ for the region.

Details Guglielmo Marconi's foundational contributions to radio communication, highlighting his 1898 Patent **7777** which introduced tuning circuits for independent simultaneous communications. Chronicles the historic transatlantic reception of the Morse code letter 'S' on December 12, 1901, from Poldhu, Cornwall, to St. John's, Newfoundland, a distance of over _3,500 kilometers_. The exhibit showcases early Marconi 10-inch spark transmitters, identical to those used on the _Titanic_, alongside Canadian Marconi crystal detector models. It also features high-end commercial receivers like the IP501, weighing **87 pounds** and originally priced at $595.00, demonstrating the robust construction and technological advancements of the era.

An home made QRM Eliminator project based on the WA1ION original design, used to remove QRN generated locally by an halogen lamp in Dutch

Original drawing and design of a 4 and 7 elements yagi antenna for 50 Mhz

Replicating vintage radio components addresses the challenge of restoring classic receivers and transmitters to their original aesthetic and functional condition. Many historical radios, particularly those from the _Golden Age of Radio_ (1920s-1940s), suffer from brittle or missing control knobs and trim pieces, making authentic restoration difficult. This resource focuses on manufacturing new parts that precisely match the originals, ensuring period-correct repairs. The service offers a vast catalog of reproduced items, with thousands of molds created since 1987. This extensive inventory includes a wide spectrum of knobs and pushbuttons, along with some plastic escutcheons, grills, and handles. The meticulous reproduction process ensures that restorers can find accurate replacements for brands like Philco, Collins, and Atwater Kent, preserving the historical integrity of these valuable pieces of radio history. The owner, Larry Bordonaro, has been in business since 1987, demonstrating deep experience in this niche.

An introduction to history of Morgain Antenna, since the early origins in Virginia, to the current home made projects and design available on the net. Article in Italian

Radio signals of natural origin

The Collins TRC-75 autotune linear amplifier, owned by JF2SVU, is presented with a focus on its internal modifications. This QRO amplifier utilizes three 4CX250 tubes in parallel for its final stage, delivering 1 KW output power. Notably, the amplifier achieves full power with only 100 mW of RF input, a characteristic often associated with Collins designs. The original 400 Hz power supply has been converted for easier shack integration, and the entire RF and power supply sections have been rehoused into a compact, clean enclosure. The control unit, positioned above the amplifier, features three meters for individual vacuum tube IP monitoring and a multi-meter on the right. A dedicated 7 MHz receiver, recently completed, is also part of this integrated system. The autotune functionality means the main amplifier unit only requires connections for power, control, and coaxial cables, simplifying its operation. Key components like the 4CX250 tubes and NF capacitors are visible, along with the gearing mechanism for the final tank circuit. A timer and relay system manages high-voltage delay and cooling fan off-delay, although the cooling fan's airflow is noted as somewhat insufficient. A central volume control, which experienced a contact issue, is also highlighted.

This article describes the antenna for Low Frequency Beacon. It originally appeared in the "Lowdown" for Oct. 1999.

The Smith Chart was originally created many years ago as an RF engineering aid by Phillip Smith of RCA.These pages includes extesnive documentation on smith carts.

Original Tuna-Tin 2 QRP CW transceiver article by W1CER

Extension to an existing fan dipole originally modeled for 40 20 and 6 meters. This modification will add 80 15 and 10 meter bands.

The HamCall.net database offers a detailed listing of amateur radio callsign divisions, organized by prefix, which is crucial for DXers and contesters to quickly identify the geographical origin of a station. Each entry includes a specific callsign prefix, the total count of callsigns registered under that prefix, and the associated DXCC country or entity, such as "AL9Z 43203 USA" or "3AOH9MM 237 MONACO." This structured data allows operators to rapidly ascertain the DXCC entity for a given callsign, aiding in QSL verification and award tracking. This information is particularly useful for confirming rare DX entities during contests or for logging contacts for awards like DXCC. For example, an operator hearing a "3Y0C" callsign can immediately identify it as Bouvet Island, a highly sought-after entity. The inclusion of callsign counts provides a sense of the activity level within each prefix, which can be helpful for anticipating pile-ups or assessing the likelihood of making a contact. The data presented reflects a snapshot of the HamCall database, offering practical insights into global amateur radio demographics.

Schematic of Yaesu FT-857 main board original jumpers based on different radio type

For amateur radio operators engaged in **radio direction finding** (RDF) and **transmitter hunting** (T-hunting) activities, this resource provides a catalog of printed circuit boards (PCBs) for constructing various DF and foxhunt-related projects. The offerings include PCBs for 80-meter fox transmitters and receivers, UHF fox transmitters with audio recording capabilities, and several designs for general-purpose radio direction finders. Specific projects like the "Simple 80M ATX-80 Transmitter" and the "N0GSG DSP Radio Direction Finder" are listed, along with attenuator boxes and specialized components for Doppler DF systems. The catalog details PCBs for projects published in prominent amateur radio magazines such as *73's*, *CQ*, *QST*, and *PE*, indicating their origin and design pedigree. For instance, the "Montreal Fox Controller" is sourced from the *Homing-In* column by Joe Moell, K0OV. The resource also lists components for advanced Doppler DF systems, including main boards, LED display boards, and antenna switch boards, with options for programmed PIC microcontrollers. Pricing for each PCB is provided, allowing hams to acquire the necessary components for their DIY RDF endeavors.

In response to a question about Numbers Stations, their origin and purpose, the following information should be of interest.

A very efficient 80 meter Counterpoise antenna designed to reduce ground losses from inadequate radial systems beneath inverted L antennas, a project by DM2GM and DM4IM based on the original K2AV antenna concept.

The 2BCX Slim Jim by F.C. JUDD, G2BCX.

The Elecraft K2 transceiver requires specific modifications for optimal soundcard digital mode operation, particularly for PSK31. The original article, circa 2001, details initial challenges with manual PTT and speech compression settings. A key modification involves adding headphone audio and a compression disable signal to the K2's microphone jack, utilizing pins 4 and 5. The **COMP0** signal, active low, is shorted to ground via a non-inverting open collector switch circuit, comprising two resistors and two transistors, mounted on the SSB board near U3. This circuit provides effective control of an analog signal line with good noise immunity. The switchbox itself repurposes a computer COM port switch, using only two of its original connectors and four of the nine poles. It integrates a microphone preamplifier, a PTT circuit built with 'flying leads' construction, and RCA jacks for soundcard connections. A trimpot adjusts the audio drive to the K2. The central DB9 connector links to the K2's mic connector via a shielded RS232 serial cable, ensuring proper grounding and signal routing. An external footswitch PTT jack is also included. Further enhancements include a **noise-canceling microphone** preamp based on a QST December 2000 article, adapted for Heil mic elements. This preamp, built with pseudo-Manhattan style construction, provides a gain of approximately 2 by changing emitter resistors (R9 and R16) from 680 ohms to 330 ohms. A 10-ohm series resistor and 47 µF capacitor on the +5V supply mitigate noise spikes.

An Unorthodox Antenna, originally by W3AWH is considered a multi-band antenna suitable for fixed location use and as an easily deployable portable antenna for events such as Field Days.

K8CU builds a classic 1967 QST semiconductor project during the 40th anniversary year of the original project publication.

For radio amateurs and electronics enthusiasts maintaining vintage tube gear, having accurate documentation for tube testers is crucial. Michael Marx, WB0SND, through SND Tube Sales, provides high-quality reproductions of these essential manuals. These aren't mere photocopies; each manual is digitally scanned, cleaned of imperfections, and professionally printed on a _Laserjet 5000_ with heavy card stock covers and plastic comb binding, often making them difficult to distinguish from originals. The catalog includes instruction manuals, schematics, and roll chart supplements for a wide array of classic tube testers. Operators can find documentation for popular models such as the _Hickok 539B/C_, _AVO CT-160_, and _B&K 700_, along with military-grade testers like the _TV-7_ and _USM-118_. Many listings also offer specialized supplements for obsolete or foreign tubes, ensuring comprehensive coverage for diverse tube collections. WB0SND's offerings extend to calibration instructions and data for specific adapters like the _Hickok CA-4_ and _CA-5_, providing critical support for precise tube testing.

The resource, initially identified as "Alabama Radio," a dealer of amateur radios, antennas, CB equipment, scanners, and power supplies in Eastern Alabama, now redirects to a domain brokerage service. The original intent was to provide a commercial outlet for Ham Radio operators and CB enthusiasts seeking new equipment and accessories. This would have included transceivers, antenna systems, and various station components. However, the current content at the URL is _Startup Domains_, a platform for buying and selling premium .COM domain names. This shift means the resource no longer serves the amateur radio community directly. Instead, it focuses on digital asset transactions, with no mention of radio equipment, _DXing_, or _contesting_ activities. The original description of a regional radio dealer is no longer applicable to the live content.

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.

Explore this high-resolution ITU Zones Map, a critical reference resource for amateur radio operators, international broadcasters, and telecommunications engineers. Originally established by the International Telecommunication Union – Radiocommunication Sector (ITU-R) Broadcasting Services Division (1999), this chart accurately divides the globe into 90 specific CIRAF zones. This authoritative visual guide is indispensable for planning High Frequency (HF) radio propagation, scheduling international broadcasts, and verifying locations for radio contests and awards. Distinct from the 40 CQ Zones, the ITU zoning system provides the official administrative framework used for global frequency management. This digitally enhanced version ensures maximum clarity of zone boundaries and numbering (e.g., Zone 28 for Central Europe), making it an essential tool for technical accuracy in logbooks and station management. It serves as a trustworthy standard for educators, hobbyists, and industry professionals alike.

Homebrewed transceiver for 20 meter originally born for 17 meters band

Article describing how to homebrew a yagi antenna for 50 MHz, includes plans for a four and five elements yagi beam and details how how match impedence with a gamma match

VE3BDB's personal page serves as a dedicated resource for members of the Radio Amateurs of Canada (RAC) residing in the Ontario South Region. Bob Cooke, VE3BDB, previously held the position of Director for this region, offering localized support and information pertinent to the RAC's activities and initiatives within Ontario South. The page likely covered regional news, events, and specific guidance for local hams, reflecting his role in facilitating communication and engagement among the amateur radio community in that area. While the page is no longer active and Bob Cooke has transitioned from his regional director role to RAC Vice President for Field Services, its original purpose was to centralize information for Ontario South hams. The content would have been tailored to address regional concerns, promote local ham radio activities, and provide updates relevant to RAC members in that specific geographic area, directing users to the main RAC website for current information.

Cloudlog is a web-based amateur radio logging application built with PHP and MySQL, supporting station logging activities from HF to microwave. It integrates with companion tools for CAT control and automation, offering a flexible solution for managing QSO data. The application provides a self-hosted platform for amateur radio operators to maintain their logbooks, facilitating interaction with various ham radio operations. Its open-source nature allows for community contributions and customization, enhancing its utility for diverse operating preferences. Originally started by Peter, **2E0SQL**, Cloudlog was designed to enable simple interaction with the Ham Radio Deluxe logbook using MySQL.

Draw static response time of an audio system. Originally intended for loudspeakers tests, is also a great tool for looking at microphone equalisation.

Edwin H. Armstrong's foundational contributions to radio technology are presented, including the _Regenerative Circuit_ (1912), the _Superheterodyne Circuit_ (1918), the Superregenerative Circuit (1922), and the complete FM System (1933). This resource functions as a curated collection of historical documents and artifacts, many previously uncirculated, stemming largely from the _Houck Collection_. The site's purpose is to offer these primary source materials for study and enjoyment, rather than to retell Armstrong's life story, which is covered in works like Lawrence Lessing's "Man of High Fidelity" and Tom Lewis's "Empire of the Air." The collection emphasizes original documents, photographs, and equipment, all sourced from the Houck Collection unless explicitly noted otherwise. The site is structured for browsing chronologically, by selected year, or by highlight, allowing users to explore Armstrong's technical evolution. Document files are intentionally large to preserve readability and detail, while individual pages are kept concise to optimize loading times. The content provides direct insight into the technical development of radio communications.

Over 100 amateur radio beacon audio files are presented, offering a direct auditory experience of propagation conditions across a wide spectrum of frequencies, from 1.8 MHz to 47 GHz. These recordings, primarily captured by IW3FZQ and IK3NWX, document signals from beacons such as DK0WCY, IY4M, GB3RAL, and S55ZRS, providing a valuable resource for **propagation study** and **beacon monitoring**. Each entry in the list specifies the beacon's callsign, its operating frequency in kHz, and the recording operator. This compilation includes signals from beacons located in various grid squares like JN55VF, JO44VQ, and IO91IN, illustrating diverse geographical origins. The frequencies covered span the 160m, 80m, 40m, 30m, 20m, 17m, 15m, 12m, 10m, 6m, 4m, 2m, 70cm, 23cm, 6cm, 3cm, 1.2cm, and 6mm amateur bands. Users can listen to these recordings to identify characteristic beacon tones and observe signal strength variations. The resource also invites other radio amateurs to contribute their own beacon audio files, fostering a collaborative archive of propagation data. The last update to this collection was on March 24, 2009, indicating a historical snapshot of beacon activity. Accessing the files requires the Real Player software.

This resource, originally intended to detail the technical specifications of the **Clover** digital communications mode, currently presents a "Page not found" error. The _Clover_ mode was designed for conveying 8-bit digital data over narrow-band high-frequency radio channels, offering robust performance under challenging propagation conditions. Its design focused on efficient data transfer and error correction, making it suitable for amateur radio operators seeking reliable digital links. The absence of the page prevents analysis of specific technical parameters, such as modulation schemes, data rates, or error correction codes that would have been presented. Historically, Clover offered significant advantages in throughput and reliability compared to earlier digital modes over HF, often achieving higher effective data rates than modes like PACTOR or AMTOR under similar signal-to-noise ratios. Without the content, a direct comparison of its performance metrics or practical application scenarios is not possible.

Aspiring radio amateurs in the United Kingdom preparing for their licensing examinations can utilize this resource, which offers mock exam questions covering the Foundation, Intermediate, and Advanced license levels. The site provides access to question pools, including associated images, designed for use with _Moodle_ learning management systems requiring PHP and MySQL. These question sets are available for non-commercial deployment by UK amateur radio clubs and organizations, facilitating local training initiatives. The original online mock test service ceased operations in August 2018 due to maintenance overhead. The current iteration serves as a repository, allowing other organizations to download the question databases. This approach enables broader access to the exam preparation material, supporting the UK amateur radio community in achieving licensing qualifications. The resource does not offer direct online testing but directs users to other sites, such as _Radio Tutor_, that implement these question banks.

The fan dipole antenna as an alternative to the paralled dipole antenna, to achieve a larger bandwidth and a better tuning by decreasing elenment influences.A project based on the W6HDG original concept.

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.

The QRPSPOTS.com domain, once a dedicated resource for QRP operators to share real-time DX spots, has undergone a significant transformation. Previously, it served the amateur radio community by providing a platform for DX spotting, including features like a telnet cluster, web cluster, JOTA cluster, and integration with RBN and PSK Reporter data. This functionality was specifically tailored to the QRP operating mode, allowing hams running low power to find and share contacts effectively across various bands. However, the current iteration of the website, as observed, no longer presents any amateur radio content. Instead, it displays information related to a Chinese educational institution, featuring sections like "About Us," "Talent Training," "Teaching and Research," and "International Exchange." The site also lists academic notices, enrollment information for international professional qualifications, and details about CPA and ACCA project classes. This shift indicates that the domain has been repurposed, moving away from its original ham radio utility. The Four State QRP Group, which previously sponsored the QRP Spots service, is no longer associated with the content presented on this URL.

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.