Search results

Types of beverage wires, choose best supports and insulators, multiple antennas at one feedpoint, all well documented with photos and exaustive explanation. This article offers insights on building Beverage antennas for optimal reception. Key takeaways include using strong wire (copperweld or electric fence), proper termination, and a good grounding system (multiple copper rods). The author recommends maximizing antenna length and orienting it towards desired stations. For best results, utilize an antenna tuner and experiment with termination resistors.

For amateur radio operators utilizing _APRS_ or requiring an external antenna for their GPS receiver, this resource details the construction of a compact, circularly polarized mobile antenna. The design is based on a classic turnstile configuration, employing two dipoles rotated 90° from each other and spaced a quarter-wavelength above a ground plane. A parallel-plate transmission line, fabricated from printed circuit board material, serves as both the connection method and mounting post for the dipoles, simplifying the feed network for circular polarization at 1.57542 GHz. The article outlines the fabrication process, starting with a 4-inch diameter hobby tin or brass base plate and #14 solid copper wire elements. It specifies using _RG-58/U_ or similar 50-ohm coax, with an 8-foot maximum length to minimize loss at the GPS frequency. The parallel-plate transmission line is constructed from two 2-inch lengths of single-sided _FR-4_ or G10 PCB material, 0.062-inch thick, with a specific 45° microwave turn cut on the active side. Final assembly involves an 8-ounce cream cheese container as a radome, and the article discusses the self-phased quadrature feed method to achieve circular polarization without a coaxial phasing line, resulting in an omnidirectional pattern suitable for GPS satellite reception.

SM0DTK's 40-meter Moxon antenna project details the construction and deployment of a wire Moxon rectangle, specifically dimensioned for the 7 MHz band. The resource outlines the use of a _Moxon Rectangle Generator_ for calculating wire lengths and the fabrication of plexiglass supports for corners and the feeding point. It describes the practical challenges of elevating the antenna to approximately **14 meters** using an aluminum tube and fiberglass rod, emphasizing the adjustment process for achieving the correct rectangular shape. The article presents comparative results against a 60-meter long-wire and a full-size 40-meter ground plane antenna. The Moxon demonstrated significant directional gain towards the west, facilitating DX contacts in the Caribbean with **100 watts**, while simultaneously reducing QRM from strong eastern European stations. The SWR was reported as perfect without the need for an antenna tuner, validating the design's effectiveness for targeted signal enhancement and interference mitigation.

This antenna article is geared towards new Hams and antenna builders looking for a very inexpensive 6 band antenna that can be efficiently fed with 50 ohm coax without a tuner by N4JTE

WorldRadio Article on Petlowany antennas base on this principle: if a length of wire is wound into a spiral-shaped coil and excited by a radio frequency current connected to the innermost portion of the coil, it will then, and only then, exhibit RF characteristics that closely approximate those of a resonant linear wire of the same length

The ultimate satellite Omni Antenna by Howard Sodja, W6SHP. The Lindenblad antenna consists of four half wave folded dipoles slanted 30 degrees to the horizon, oriented 90 degrees to each other in azimuth, spaced 0.3 wavelength apart

Constructing a Lindenblad antenna for 137MHz NOAA satellite reception involves specific design considerations for optimal performance. The resource details the use of 4mm galvanised steel fencing wire, 300-ohm television ribbon cable, and wood/plastic components for the antenna structure. Key dimensions for a 137.58MHz-resonant antenna are provided, derived from the ARRL Satellite Handbook, specifying s, l, w, and d as 42, 926, 893, and 654mm respectively. The antenna is designed for Right Hand Circularly Polarised (RHCP) signals, requiring the four folded dipole elements to be tilted clockwise by 30 degrees. A significant aspect covered is impedance matching between the antenna's 75-ohm impedance and a typical 50-ohm receiver input. A twelfth-wave matching transformer, constructed from 117mm sections of 50-ohm RG-58 and 75-ohm RG-59 coax with a 0.66 velocity factor, is described. The article also addresses coaxial cable and connector selection, recommending 75-ohm Type-N connectors for RG-6 cable in professional setups and F56/F59 connectors for general use, while strongly advising against PL-259/SO-259 connectors for VHF. Strategies for mitigating Radio Frequency Interference (RFI) are discussed, including antenna placement to shield from local TV transmitters and the use of commercial or DIY band-pass filters, such as cavity resonators or helical notch filters, along with ferrite chokes on coaxial cables. Antenna orientation is explored, noting the Lindenblad's 'cone of silence' directly overhead and its maximized sensitivity towards the horizon. An experimental vertical tilt of 90 degrees is presented as a method to improve overhead reception and reduce interference from strong horizontal signals, particularly relevant in high RFI environments like the Siding Spring Observatory site.

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

This online article provides a list of individuals who hold or have held amateur radio callsigns, detailing their public recognition. The resource identifies specific callsigns such as **K1JT** (Joe Taylor, Nobel Prize in Physics), **W6OBB** (Art Bell, syndicated radio personality), and **JY1** (King Hussein of Jordan), linking them to their non-amateur achievements. It also notes operational statuses like _Silent Key_ for deceased operators and _lapsed callsign_ for inactive licenses. The article includes information on callsign changes due to vanity callsign programs and provides examples of individuals involved in specific technical areas, such as Percy L. Spencer (**W1GBE**), inventor of the microwave oven, and Jay Kolinsky (**NE2Q**), inventor of electronic sirens. It also references amateur radio involvement in _space missions_ for individuals like Owen Garriot (**W5LFL**) and Helen Sharman (**GB1MIR**). DXZone Focus: Online Article | Famous Hams | Callsign Status | Vanity Callsigns

Microwaves articles, The Technology Voice of the Wireless World , need registration to access

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.

PalmProp is a software for PalmOs dedicated to the forcast of HF radiowave propagation by f5hla

This antenna article is geared towards new Hams and antenna builders looking for a very inexpensive 6 band antenna that can be efficiently fed with 50 ohm coax without a tune

The SETI League, Inc., founded in 1994, focused on participatory science, developing technology to seek definitive answers to the question of extraterrestrial intelligence. The organization operated in five dozen countries across all seven continents, maintaining the quest for cosmic companions through the efforts of its 1500 members. Although the organization shuttered its virtual doors after thirty years in 2024, the website remains for educational and historical purposes, documenting past research and activities. Key technical resources include the _SETI League Mini-Manual_ for constructing a 12 GHz radio telescope under $200, and software like _SETIFox for Windows_ and _Radio Eyes_ for radio astronomy sky viewing. The site also features _Project Argus_ detections, moonbounce signal detections, and space probe signal detections, providing concrete examples of amateur radio astronomy applications. Publications such as the quarterly newsletter _SearchLites_ and various articles by Dr. SETI (H. Paul Shuch, Ph.D.) are available, alongside information on the Third Penn State SETI Symposium in 2025. The site also offers insights into hydrogen line emission observations, presented in time domain, frequency domain, waterfall, and surface plot formats.

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.

WA1MBA article on RF connectors for microwave

On December 12, 1901, Guglielmo Marconi successfully received the first transatlantic wireless communication, a Morse code "S" (three dots), at 04:30 GMT. This article details the setup for this groundbreaking experiment, noting Marconi's receiver in St. John’s, Newfoundland, Canada, utilized a _coherer_ and an antenna elevated by balloons and kites. The transmitting station at Poldhu, Cornwall, England, featured twenty-four 200-foot ships' masts and a 25-kilowatt alternator. The resource explains how this contact disproved contemporary beliefs about radio wave limitations due to Earth's curvature, later understood through _ionospheric propagation_. It frames Marconi's achievement as the "very first DX" in amateur radio terms, defining DX as telegraphic shorthand for distance and _DXing_ as the hobby of receiving distant signals. The article also provides external links for further reading on Marconi's experiments and the science behind transatlantic radio signal reception.

The project in this article illustrates how to do this in a simple and low cost way so that you can easily access the microwave bands using the existing HF or HF/VHF transceiver as IF.

Article about the microstrip patch antennas, and in particular the rectangular, single-polarization microstrip antennas, commonly abbreviated MSA.

An article on amplitude modulation (AM) operation on VHF bands.

A transmitting antenna 2x15m, about 100 foot doublet antenna fed by a ladder line of about 600 Ohm. Article in Polish and English,

Direct conversion receivers (DCR) are gaining renewed interest due to advancements in semiconductor technologies and their suitability for integration in compact, low-cost, multi-standard applications. Unlike traditional superheterodyne receivers, DCR eliminates image frequencies and bulky off-chip filters but introduces challenges like DC offsets, nonlinearity, and noise issues. This tutorial explores DCR's historical development, compares it with other receiver architectures, and addresses its inherent obstacles. DCR's potential for integration and compatibility with software-defined radio highlights its role in modern communication systems despite its technical complexities.

Optimizing directional gain on the 40-meter band often involves complex antenna designs; this resource details the construction and performance of a reversible _Moxon_ array. The design provides directional coverage from southeast to west, with a switching mechanism to reverse the pattern towards east to northwest. Key design considerations include precise element spacing, the critical role of coil inductance for proper resonance, and the use of _NEC5_ for accurate electromagnetic modeling, ensuring the antenna performs as predicted across the desired frequency range. The antenna's performance is evaluated through on-air contacts, demonstrating effective signal propagation to regions like the Caribbean, South/Central America, the US, and Europe. The article presents measured SWR plots and gain patterns, comparing them against the _NEC_ model predictions to validate the design's efficacy. Practical application notes cover mounting considerations and the benefits of its reversible pattern for targeted DXing on 40 meters, offering a robust solution for operators seeking enhanced directional capabilities without a full-sized rotating Yagi.

This article from the July 1976 issue of Radio REF discusses the trend of large antennas for ham radio operators on the low bands. It specifically focuses on a Yagi 2 element antenna for the 80m band, detailing its construction and functionality. The author explains how the antenna can be switched between directing signals towards the West or East using a switch at the station. The article also provides technical details on the lengths of the director and reflector elements, and how they impact the antenna's performance. A useful resource for hams looking to build or understand Yagi antennas for the 80m band.

The article explores the concepts of return loss, VSWR, and S11 within the context of microwave engineering, highlighting the confusion arising from their definitions. It clarifies that these parameters, while seemingly distinct, fundamentally describe the same phenomenon related to wave reflection and transmission in microwave circuits. The discussion emphasizes the historical context and mathematical relationships among these terms, revealing that their interpretation can vary significantly across different engineering disciplines. Ultimately, it advocates for a pragmatic approach to using these parameters based on familiarity rather than strict definitions.

The W6PQL 23cm Beacon Project describes a **1296 MHz** beacon designed for microwave propagation studies and equipment testing, capable of 30 watts output. It utilizes a PIC 16F628A microcontroller to generate CW and FSK keying for a crystal oscillator, followed by a series of frequency doublers and triplers to reach the target frequency. The final power amplification stage employs a Mitsubishi M57762 module, providing a robust 10-watt RF output. The design emphasizes stability and reliability for continuous operation, with the microcontroller code, written in assembly, provided for customization of the beacon's callsign and message. Originally located in CM97am and aimed at 140 true, the beacon used four 4-foot Yagis stacked vertically for a total ERP of 3kW. The article includes schematics, parts lists, and construction notes to guide builders, along with antenna pattern measurements. Although the beacon itself is no longer in service as of August 2010, the detailed documentation remains a valuable reference for amateur radio operators interested in building similar **microwave** projects or understanding beacon operation.