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A 4 AMP / 18V regulated power supply schematic, designed by _ON6MU_, provides a detailed circuit diagram for constructing a robust power source. The design focuses on delivering a stable 18-volt output at up to 4 amperes, crucial for powering various amateur radio equipment. This resource presents a clear visual representation of component interconnections, including rectifiers, filter capacitors, and voltage regulation stages, essential for DIY enthusiasts building their shack infrastructure. The schematic's clarity facilitates understanding the power flow and component roles within the circuit. This circuit design offers a practical solution for hams needing a reliable 18V supply, potentially useful for driving specific transceivers, amplifiers, or accessory circuits. While specific performance measurements or comparisons to other designs are not detailed, the schematic itself serves as a foundational blueprint. Builders can adapt or modify the _power supply_ to suit their particular needs, such as integrating overcurrent protection or fine-tuning the output voltage with adjustable regulators. The straightforward presentation makes it accessible for those with basic electronics knowledge to assemble and troubleshoot.

Hidden transmitter hunting, often called fox hunting or Amateur Radio Direction Finding (_ARDF_), presents a unique challenge for radio amateurs. This resource details the _PicCon_ controller, a specialized device designed to automate the transmission of signals for such events. It integrates with a standard radio transceiver, functioning similarly to a packet radio TNC, by controlling the Push-To-Talk (PTT) line and injecting audio tones or modulated CW Morse code into the microphone input. The _PicCon_ unit is field-programmable using DTMF tones received via the radio, storing all settings in EEPROM for power-off retention. Its compact design and low power consumption (a few milliamps from a 7-35VDC source) make it suitable for remote deployment. An onboard LED indicates operational status, and a push-button allows manual start/stop of transmissions without DTMF. Typically supplied as a kit, _PicCon_ includes a PCB, components, and a comprehensive manual (available in HTML, RTF, and PDF formats). The kit provides a six-conductor interface cable, but users must supply radio and power plugs due to varied configurations. Byon, _N6BG_, developed this controller, which is available from the Byonics website.

Optimizing the ZS6BKW antenna for full HF band coverage often requires specific modifications beyond its standard configuration. This resource details several enhancements, beginning with a simple series capacitor to improve 80m SWR, a technique W5DXP found effective for permanent installation due to its minimal impact on higher bands. Further improvements include a 10-inch parallel open stub for 10m resonance, shifting the frequency to 28.4 MHz with an SWR of approximately 1.8:1, a practical solution for Technician class operators. The document then explores a switchable matching section, adding or subtracting one foot of ladder line at the 1:1 choke-balun, which significantly impacts higher frequency bands and eliminates the need for a tuner on 17m. W5DXP's _AIM-4170D_ antenna analyzer measurements confirm these effects. More advanced modifications involve a parallel capacitor for further 80m SWR reduction, requiring remote switching for multi-band operation, and relay-switched parallel capacitors at specific points on the 450-ohm matching section to achieve low SWR on 60m, 30m, and 15m. These detailed steps, including _Smith chart_ analyses for the challenging bands, aim to transform the ZS6BKW into a truly all-HF-band antenna, reflecting W5DXP's practical experience in antenna tuning.

One point eight MHz to 30 MHz is the operational bandwidth for this 4:1 Ruthroff voltage balun, designed to interface an unbalanced T-Match network with a balanced antenna system. The project details the construction using a _T200-2_ powdered iron toroid core, tightly wrapped in PVC electrical tape for insulation, and wound with 17 double bifilar turns of 1.25mm enamelled copper wire. This outboard balun offers flexibility, allowing hams to trial various baluns based on antenna system and impedance characteristics, rather than integrating it directly into the tuner. The resource includes a schematic of the balun, a wiring diagram showing winding connections, and a table suggesting alternative toroid cores like the T80-2 or T400-2 with corresponding winding counts. Component sourcing is straightforward, listing items such as the _Amidon_ T-200-2 core, SO-239 connector, and a sealed polycarbonate enclosure from Jaycar. Performance evaluation was conducted using an _AIM 4170C_ antenna analyser, demonstrating efficient 1:4 voltage transformation across the specified HF spectrum. Further efficiency tests involved measuring RF power loss at various frequencies, revealing minimal loss—less than 0.7 dB from 3.6 MHz to 30 MHz, and only 2.0 dB at 1.8 MHz. These measurements, performed under ideal 50-ohm conditions, confirm the balun's effectiveness as a low-loss interface for multi-band antenna systems. The page also links to several other balun and unun projects, including 1:1 current and voltage baluns, and 9:1 voltage ununs, providing a broader context for impedance matching solutions.

Crystal-controlled QRP tranceiver by F6BCU for 80 meters band 1W output

The resource presents a detailed schematic for constructing a dual-band vertical antenna, specifically designed for operation on the 2-meter and 70-centimeter amateur radio bands. It illustrates the physical layout, critical dimensions, and component placement necessary for successful replication. Key elements such as the radiating elements, phasing sections, and feed point are clearly depicted, providing a visual guide for radio amateurs undertaking a homebrew antenna project. The diagram specifies the lengths for the VHF and UHF sections, indicating how these elements are integrated to achieve dual-band functionality from a single coaxial feedline. It also implies the use of common materials readily available to most experimenters, focusing on simplicity and effectiveness in its design. The visual format of a GIF image ensures direct access to the construction details without requiring extensive textual interpretation. This schematic serves as a practical reference for hams interested in building a compact, efficient vertical antenna for local and regional FM communications, offering a proven design for immediate implementation.

A 2-meter Moxon beam antenna, designed for the _144 MHz_ band, is detailed, originating from a desire to participate in the PW 2m QRP contest. The design, based on a Moxon Rectangle, offers a compact directional solution for VHF portable operations. The author, G0KYA, constructed the antenna using readily available materials like 15mm plastic conduit for the frame and 1.5mm copper wire for the elements. Initial testing with an MFJ-259B antenna analyzer showed a **1.2:1 SWR** at 144.300 MHz, indicating good resonance. The antenna's compact size, approximately 70cm x 40cm, makes it highly suitable for portable QRP work, providing a significant advantage over an omnidirectional vertical. The project includes practical advice on element spacing and construction techniques, emphasizing ease of assembly for field deployment. Field results from a local hilltop demonstrated the Moxon's directional characteristics, allowing for effective nulling of local noise and improved signal reception from specific directions.

Presents a curated collection of newsletters dedicated to _Earth-Moon-Earth_ (EME) communications, primarily focusing on the 432 MHz band and higher microwave frequencies. The resource details various EME DX experiences and news contributions from operators like K2UYH (W6/PA0ZN), offering insights into successful moonbounce contacts and operational strategies. It serves as an archive of specialized content for those engaged in or interested in extreme weak-signal propagation via the moon. The newsletters provide practical information on achieving EME contacts, often including details on station setups, antenna arrays, and signal reports from challenging DX. For instance, operators might report achieving contacts over **750,000 km** round trip, demonstrating the feasibility of long-distance communication on UHF and microwave bands. The content differentiates itself by concentrating on the unique technical and operational aspects of EME, which contrasts significantly with terrestrial DXing, providing a specialized knowledge base for advanced amateur radio operators.

The page provides a project for an helical dipole for the 40 meters band, resonating on 7 MHz, created by PY1ZFK based on a design by DL8VO. It includes detailed instructions on building the antenna.

Presents _HamQTH_, a free online callbook and callsign server, which provides rapid XML access for various logging programs, enabling seamless integration for amateur radio operators. The service includes features such as recent activity logs, propagation predictions, and support for multiple languages, making it a versatile tool for DXers and contesters. It also offers detailed information on callsigns, including US states, counties, IOTA, WAZ, and ITU zones. Users can leverage _HamQTH_ for efficient log searching and to monitor current band conditions, aiding in planning DX operations and contest strategies. The platform's XML interface facilitates automated lookups, streamlining the process of identifying stations and gathering essential QTH data. Petr Hlozek, OK2CQR, developed this resource, reflecting practical experience in amateur radio data management.

Presents a QRP AM/CW transmitter project specifically designed for the 10-meter band, utilizing a crystal oscillator and a collector-modulated AM oscillator. The design employs a 2N2219(A) transistor in a Colpitts configuration, generating 100 to 350 mW of RF output power depending on the 9-18 Volt supply voltage and modulation depth. Frequency stability is maintained by a 28 MHz crystal, with fine-tuning possible via a Ct1 trimmer capacitor for approximately 1 kHz adjustment. The resource details the RF oscillator stage, implemented with a 2N2219 NPN transistor, emphasizing frequency stability and low power dissipation. It also covers the amplitude modulation stage, managed by a 2N2905 PNP transistor, which impresses audio information onto the carrier. Selective components (C3, C4, C7, C5) enhance voice frequencies within a +/- 5 kHz bandwidth, and modulation depth is controlled by R2 and R3. The project includes a 3-element L-type narrow bandpass filter (Ct3, L3, C10) to suppress harmonics and ensure a clean output signal. The project provides a complete schematic diagram, a comprehensive parts list including specific capacitor, resistor, and inductor values, and construction notes for the coils (L1, L2, L3). It also offers practical advice on enclosure requirements, suggesting an all-metal case or a PVC box with graphite paint for RF shielding. Operational parameters such as current draw (27mA@9V to 45mA@16V) and input impedance (50 Ohms) are specified, alongside guidance on antenna matching and the importance of a valid amateur radio license for 10-meter band operation.

Examines Kiwa, a global entity specializing in **Testing, Inspection, and Certification (TIC)** services across diverse sectors. The resource details Kiwa's operational scope, which encompasses quality assurance, safety compliance, and sustainability solutions for industries such as Food, Feed and Agriculture, Digital and Cyber Solutions, Energy Transition, Industrial Services, and Medical Devices. It highlights the company's role in ensuring product, service, process, and system integrity through rigorous accreditation and notification processes, operating in over 35 countries worldwide. The content presents specific examples of Kiwa's engagement, such as food safety certification for HortaPronta in Portugal, explanations of the Digital Battery Passport requirements, and contributions to floating offshore wind energy development. It also outlines the company's approach to biological evaluation of medical devices according to **ISO 10993** and its commitment to ESG principles, as detailed in its online ESG magazine, Trace. The resource provides access to a certificate finder and a testing directory with over 3000 capabilities across 80 laboratories.

A Variable Base-Loading-Coil provides a practical solution for optimizing HF mobile whip performance across multiple bands. The design, as presented by VK4ADC, details a coil wound on a 50mm PVC former, utilizing 1.6mm enamelled copper wire for robust construction. This approach allows for precise tuning, a critical factor in achieving efficient radiation from a mobile setup, where antenna length is often compromised. My own field experience with similar base-loaded whips confirms the importance of a well-designed loading coil for maximizing signal strength and minimizing SWR. The VK4ADC design incorporates a sliding contact, enabling continuous adjustment, which is superior to fixed taps for fine-tuning resonance on the fly. This variable inductance allows the operator to quickly adapt the antenna to different HF segments, from 80 meters up to 10 meters, without needing to swap out multiple coils. The document includes specific winding data, such as the number of turns per inch and the overall length of the coil, which are essential for replication. It also touches upon the mechanical aspects of integrating the coil with a standard mobile whip, ensuring a stable and weather-resistant assembly for reliable operation during mobile DXing or casual rag-chewing.

The _Italian VHF Beacons_ resource provides a detailed listing of active and QRT amateur radio beacons operating across VHF, UHF, and SHF bands within Italy. Each entry specifies the beacon's callsign (e.g., IQ1SP/B), operating frequency (e.g., 144.411 MHz), QTH locator (e.g., JN44VC), effective radiated power (ERP) in watts, and antenna configuration (e.g., Big Wheel, 4x Dipole, Yagi). This data is crucial for radio amateurs involved in propagation studies, equipment testing, and long-distance (DX) communication on these higher frequency bands, offering fixed signal sources for monitoring. This compilation, last updated in October 2005, serves as a historical snapshot of Italian beacon activity. For instance, it lists several 144 MHz beacons with ERPs ranging from **0.1W** to **10W**, and higher frequency beacons such as I8EMG/B on 1296.880 MHz and I3EME/B on 24192.132 MHz. The inclusion of QRT (Quiet Radio Teletype) status for many entries indicates the dynamic nature of beacon operations over time. Users can utilize this information to identify potential signal sources for band openings or to calibrate their receiving equipment against known transmissions.

T2FD A practical construction article, which first appeared in the Electronic DX Press, contains a number of useful photos and detailed instruction to build this antenna by VK3BVW

Detailed online and searchable maps, driving directions and city guides

This is an Android application used to remotely control several HAM radio Web SDR or any CAT enabled transceiver

Operating on the 2200m band (135.7-137.8 kHz) often presents challenges for amateur radio transceivers, which typically exhibit poor receiver performance at these very low frequencies. This project addresses the issue by providing a design for a dedicated 137 kHz antenna preamplifier, specifically tailored to improve signal reception for radios such as the _Yaesu FT-817_. The preamplifier circuit utilizes a low-noise FET input stage, crucial for minimizing self-generated noise and maximizing the signal-to-noise ratio from weak LF signals. The design includes a detailed schematic, component values, and construction notes, enabling homebrewers to build a functional unit. The goal is to achieve significant gain, making the faint signals on 2200m more discernible and improving overall band usability. Key design considerations include impedance matching to typical antenna systems and ensuring stable operation across the narrow LF segment. The circuit aims for a **low noise figure** and sufficient amplification to overcome the inherent limitations of general-purpose HF transceivers when operating below **200 kHz**.

Operating an 80/40/20M fan dipole for DX is analyzed through EZNEC modeling, focusing on the antenna's performance in a real-world, low-height installation. The resource details the physical construction and SWR measurements of the fan dipole, comparing them against EZNEC simulations. It also incorporates High Frequency Terrain Analysis (HFTA) data to illustrate typical DX elevation angles for various regions from New England, providing a crucial context for evaluating antenna patterns. The analysis presents EZNEC-generated azimuth and elevation patterns for each band (80M, 40M, 20M) at specific frequencies, showing gain figures at different elevation angles relevant to DX propagation. It compares the modeled SWR with measured SWR, attributing discrepancies to coax attenuation. The study concludes with observations on the antenna's azimuth performance (omnidirectional within ±1.5 dB) and its less optimal elevation gain at desired DX angles, highlighting the impact of low antenna height on DX capabilities.

The webpage provides guidance on working 6 Meter DX, focusing on effective operating habits, preparation, and knowledge of the band. It emphasizes the importance of monitoring, clear frequencies, and using CW for weak signals. It also mentions the significance of knowing countries and individual stations on the air to increase chances of working DX. The page recommends utilizing resources like newsletters and websites to stay updated on 6-meter activity and offers suggestions for improving operating skills.

A two meter Quad antenna project with detailed instructions on how to adjust the Quad gamma match

This Z-Match is a link coupled all-band tuner. Two all band tank circuits cover 3-14mhz and 14-30mhz. The tank output links are selected with a very heavy duty SPDT rotary switch.

The NiCd Lady Company has been in the business of assembly and distribution of batteries since 1994, supplying government, industry and retail with a wide variety of batteries, and production of assembled products.

The 3Y0K Log Online provides a detailed logsearch interface for the **3Y0K** DXpedition to Bouvet Island, scheduled for February 2026. This web-based tool, hosted on _Club Log_, allows users to access real-time QSO statistics and leaderboards. The interface includes interactive features such as a map for checking real-time propagation and colored boxes that reveal mode and time breakdowns when hovered over. The service supports HF bands and provides a structured overview of QSOs, including band/mode breakdowns and continent-specific data. Users can report logging inquiries and QSL requests exclusively through the M0OXO Online QSL Request System (**OQRS**). The site also offers additional resources like band plans, operating practices, and FT8 advice. The leaderboard feature, which includes clubs and Contest Club, ranks stations based on the number of band slots worked, with duplicate QSOs being discouraged. The expedition's impact on users' totals is also tracked, providing insights into new bands, modes, and DXCC entities worked. DXZone Focus: 3Y0K DXpedition | Club Log | Bouvet Island

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.

The NL Ham Radio Swap Shop is an online platform dedicated to connecting amateur radio operators in Newfoundland and Labrador with opportunities to buy, sell, and trade radio equipment. This service caters to both seasoned operators and newcomers, providing a space for exchanging second-hand gear, military radios, antique radios, and radio tubes. Users can browse listings, post their own items, and find unique equipment that may not be available in traditional retail outlets. In addition to facilitating transactions, the Swap Shop also serves as a community hub for local hams. It encourages networking among operators, sharing of knowledge, and collaboration on projects. Whether you are looking for a rare piece of equipment or simply want to declutter your shack, the NL Ham Radio Swap Shop is an essential resource for anyone involved in the amateur radio hobby in the region.

Sherwood Engineering Inc. (SEI) offers a repository of technical presentations and white papers focused on optimizing amateur radio transceiver and receiver performance. Content includes detailed analyses of _roofing filters_, transmitted IMD, and receiver characteristics, with specific discussions on products like the Drake R-4C and Icom IC-781. Presentations from events such as Dayton Contest University (2008-2014) cover topics like "How To Optimize Rig Performance," "Transceiver Performance: 10 Years of Change," and "Choosing a Transceiver: Far from Simple." Additional white papers address HF mobile antenna efficiency, ground screen alternatives to buried radial systems, and common receiver problems with solutions. The site also provides historical product information for items like the SE-3 MK IV synchronous AM detector and various 455 kHz mechanical and crystal filters, though many products are no longer in production. Receiver test data and alignment tips for the R-4C are also available, offering insights into rig modifications and performance enhancements.

Showcases the Del City Amateur Radio Club (W5DEL), an organization serving the amateur radio community in Del City, Oklahoma. The club facilitates local ham radio activities and provides a platform for members to connect. It emphasizes community engagement through various events and resources, supporting the interests of local operators. The club's online presence, while functional, appears to be a repurposed template, with some content not directly relevant to amateur radio. Members can access information on club dues, upcoming events, and community guidelines. The site mentions a focus on VoIP, suggesting an interest in **digital voice modes** and **internet-linked radio systems**. Although specific technical projects or operating achievements are not detailed, the club aims to foster camaraderie and provide a local point of contact for hams in the Del City area.

The Remote Control Antenna Switch consists of two circuit boards. The control unit and the remotely controlled switch

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.

Operating on the 11-meter band, the Alfa Tango Argentina website serves as a digital hub for CB radio DX enthusiasts, particularly those affiliated with the _Alfa Tango_ international group. The resource primarily functions as a community portal, facilitating connections among members and promoting activities related to long-distance CB communications. It presents basic information about the group's presence in Argentina and emphasizes the social aspect of radio communication, framing participants as "friends who have never met." The site's content reflects the operational focus on **DXing** within the CB radio sphere, a practice that mirrors amateur radio's pursuit of distant contacts. While specific operational data or technical guides are not detailed, the site's existence supports the organizational structure of the Alfa Tango group, which coordinates activities across various countries.

An example of how to control a Yaesu FT-817 with an Arduino to make a multi-band CW beacon.

Detailed pictures and description of antenna tower setup

This page describes an cheap RF signal source, a portable micro beacon, using a low cost temperature controlled crystal oscillator

Examines the Icom IC-2100H 2-meter mobile transceiver, detailing its operational characteristics and user experience. The review highlights the clear, easy-to-read display with internal labels, the button-filled microphone's functionality, and the rig's physical construction, including its weighty heat-sink and lack of a cooling fan. It also discusses memory programming, the unique amber-to-green backlight color options, and the radio's performance against _intermodulation_ in urban environments, noting it performs "pretty darn good" compared to other rigs. The analysis delves into a significant low-voltage cutoff problem, where the microphone ceases to function below approximately **12.6 VDC**, rendering the radio receive-only or causing it to stick in transmit. The author describes testing the voltage cutoff, observing it fluctuate from _12.38 VDC_ to 12.69 VDC. An update from Icom involved a "factory update" to the CPU's control code, which is strongly recommended for early-serial number units to prevent operational failure in low-power emergency scenarios.

The Yaesu FT-1000MP Mark-V, introduced at Dayton 2000 Hamvention, features a higher RF power of **200 W PEP** and a Class-A amplification SSB mode at 75 W. Key enhancements include an _Interlocked Digital/Analog Bandwidth Tracking system (IDBT)_, a Variable Front-End Filter (VRF) preselector, and improved ergonomics, notably a multi-function shuttle jog dial. This model, a successor to the 1996 FT-1000 and FT-1000MP, was designed to compete with high-end transceivers, despite its retail price of $4200 initially. The transceiver's physical dimensions are 406 x 135 x 348 mm (16 x 5.3 x 13.7 inches) with a weight of 14 kg (31 lbs), making it substantial. Its rear panel offers over 20 connections, including power, external DSP speaker, BAND DATA I/O, ALC, and multiple interface jacks for DVS-2, Packet, and RTTY. The unit also provides two keyer inputs, a DB9M serial interface for CAT, and two PL female antenna connectors, plus additional receive antenna jacks. Despite its advanced internal architecture, including two independent receivers with their own IF filters and AGC loops, the display technology, utilizing fluorescent discharge rather than LCD, contributes to an older aesthetic. The control panel is extensive, featuring 92 knobs and buttons, alongside numerous LED indicators for various modes and functions.

A large collection of crystal controlled scanners

Basic information compiled and copied from NOAA SEC explaining and showing current solar weather conditions affecting amateur radio.

Presentation by AC8GY on classic G5RV Antennas and other horizontal dipoles, the popular G5RV, ZS6BKW, dipole fan, Alpha-Delta DX-CC and a trap dipole are modeled in EZNEC and compared.

The document titled 'Extending the Range of Your Handheld' by WG7S is a guide on how to extend the range of your handheld VHF UHF transceiver by using an external antenna. It provides information on comparing popular models, selecting the right antenna, and resources for amateur radio antennas.

This electronic board will be installed over a Raspberry Pi CPU card to provide a repeater controler. All features are software controlled with the famous SVXLINK and other interessed modules.

The KP3AV Systems website offers a detailed listing of amateur radio repeaters across Puerto Rico, including operational frequencies and tones for VHF and UHF bands. It features sections dedicated to digital modes like DMR and C4FM, as well as information on FRS, GMRS, and MURS. The resource also includes articles on emergency communications protocols and provides access to Spanish-language manuals for various radio equipment. Recent content covers the new open-source FT2 mode for WSJT-X Improved, upcoming 60-meter band frequency allocations and power restrictions effective February 13, 2026, and discussions on 2-meter contacts with Desecheo Island from Puerto Rico. The site also presents U.S. amateur radio band plans and highlights local contesters like Manuel WP4TZ, offering practical insights into portable operations and contest participation.

A live map of current KiWiSDR receivers available on the network. It allows users to explore a directory of web-controlled receivers for listening to HF and VHF stations worldwide. The site provides access to remote ham radio stations online, making it a valuable resource for amateur radio operators.

Mission is to preserve the history and enhance the knowledge of radio.

The ZS6BKW multi-band antenna, an optimized variant of the classic G5RV, is presented with detailed construction and tuning instructions. This resource outlines the antenna's design principles, which were developed by _Brian Austin (G0GSF)_ using computer programs and Smith charts to achieve optimal dimensions. It provides specific guidance on calculating and adjusting the lengths of the radiators (L1) and the matching ladder line (L2), emphasizing the critical role of velocity factor (VF) in achieving resonance. The article includes a step-by-step procedure for empirically determining the VF of ladder line using an antenna analyzer, ensuring accurate physical lengths for the matching section. It details the tuning process for the radiators, offering practical tips for incremental adjustments to achieve the best SWR curve. The resource presents SWR measurement results obtained with an _AIM-4170C_ analyzer across multiple bands, alongside predicted SWR graphs from an AutoEZ model. It confirms successful contacts on 80, 40, 20, and 17 meters, including a **17-meter DX contact** to Italy. EZNEC and AutoEZ models for the ZS6BKW antenna, covering 80 through 6 meters, are provided for download, allowing further analysis and customization. The document specifies component details, such as the use of Wireman 554 ladder line and #14 AWG THHN copper wire, and discusses the antenna's performance characteristics, noting high SWR on 15 and 30 meters but successful tuning on 6 and 80 meters with an external tuner.

Dish antenna and its theory and design for high performance applications such as satellite transmission and reception as well as microwave links. Parabolic Reflector Antenna: Dish Antenna The parabolic reflector antenna which is often called the dish antenna provides an antenna solution applicable for VHF and above where high gain and directivity are needed for all type of radio communications and radio reception.

The Receiver Test Data resource is a detailed review database focusing on the performance metrics of various radio receivers. The methodology involves rigorous lab measurements, often adhering to standards such as the ARRL RMDR (Reciprocal Mixing Dynamic Range) and BDR (Blocking Dynamic Range). Specific test equipment and protocols are utilized to assess parameters like noise floor (dBm), AGC threshold (uV), and LO noise (dBc/Hz). For example, the _Icom IC-7300_ is evaluated with a noise floor of **-133 dBm** and an LO noise of **-141 dBc/Hz**, providing insights into its performance under different operational conditions. The resource includes a wide range of models, from the _Elecraft K3S_ to the _Yaesu FTdx-101D_, each tested for dynamic range, sensitivity, and selectivity. The data is sorted by key metrics such as third-order dynamic range and phase noise limitations, with RMDR values calculated by subtracting 27 dB from LO noise figures. This structured approach allows users to compare different receivers' capabilities, focusing on technical specifications and performance outcomes in various scenarios. DXZone Focus: Review Database | Lab Measurements | -133 dBm | ARRL RMDR

6 Meter 1/4 Wave Antenna by Mike Fedler N6TWW. A detailed article with pictures of construction details of this 50 Mhz antenna

A simple antenna analyser for the HF spectrum with a built-in signal generator with 3-digit LED frequency display.

The resource details the construction of a homebrew 50-watt FET amplifier, based on Don W6JL's _QST Homebrew contest_-winning design from 2009. It functions as an afterburner for QRP transceivers, providing a **12dB** power lift. The amplifier utilizes IRFZ24N FETs and covers the 80, 40, 30, and 20-meter bands, with the 20m LPF extending to 17m. Key technical aspects include an FT37-43 transformer for the input network, a relay-switched 3dB pad for lower bands controlled by an _Arduino Nano_, and an RF-actuated T/R switch. The LPF board integrates four relay-switched filters rated for 50 watts, using capacitors with a minimum 250VDC rating. Performance measurements indicate a power gain ranging from **4.4dB** on 20m to 8.1dB on 80m, with a required drive power of approximately 5 watts. The article also discusses thermal management, current limiting considerations, and component sourcing.