Search results

This article explores the marriage of amateur radio and bushcraft, advocating the pleasure of setting up a portable station in nature rather than operating from the confines of a vehicle. The Parks on the Air (POTA) programme is highlighted as a catalyst for outdoor radio activities. The author shares his experiences and techniques, from transporting equipment into the wilderness to setting up shelters and antennas. Knot tying skills and the use of frogs are emphasized for efficiency, and a unique method for launching wire antennas is described. The article emphasizes the synergy between amateur radio and bushcraft skills, enhancing the enjoyment of radio operations in wilderness environments.

This presentation on antennas is a practical guide for amateur radio operators. The key takeaway is that the best antenna for your station depends on your constraints and goals. There is no magic solution and buying a wire antenna is not recommended as it might be expensive and not as effective. The presentation covers different antenna types including dipoles, verticals, Yagis and loop antennas. Important factors to consider when choosing an antenna include SWR, feeder types, and whether you need a balun. The author emphasizes that ATUs don’t improve a poor antenna and advises against obsessing over SWR readings.

This article details the development of an 80-meter antenna within the confines of a restrictive covenant community. Faced with limited space, the author explores various options before implementing a clever hybrid design: a short 30-foot vertical wire running discreetly down the building's exterior combined with a capacitive top hat installed in the attic. Computer modeling confirmed the superiority of capacitive loading over inductive loading, increasing radiation resistance from 6 to 14 ohms. The perimeter wire top hat, naturally supported by the attic structure, resonates effectively at 3.5 MHz. The system is completed with four buried 60-foot radials installed "after dark" to maintain compliance with community restrictions.

WB5NHL describes setting up a 160-meter antenna on a small suburban lot, where standard options like Beverage antennas and 1/4 wavelength verticals require extensive space and ground systems. Instead, Guy Olinger's Folded Counterpoise (FCP) provides a solution. The FCP minimizes ground losses by using a folded wire design, allowing effective antenna placement in limited space. The FCP, fed with an isolation transformer, enabled WB5NHL's first 160-meter antenna installation, offering improved performance despite space constraints.

Demonstrates the construction and portable deployment of a 40-meter horizontal loop antenna, often referred to as a "Sky Loop" or "DX-Buster." The design adapts a full-wavelength horizontal loop for field use, eliminating the need for traditional insulators by employing four 5-meter heavy-duty _squid poles_ and metal post bases for support. This setup facilitates rapid assembly, crucial for portable operations, with the antenna wire length specified at approximately 43-45 meters for optimal 40-meter band performance. The resource details the specific construction methodology, including winding the antenna wire around rubber caps on the squid poles and securing it with electrical tape. It provides a parts list and assembly techniques, focusing on minimizing components for ease of transport and quick setup. The article, originally published in the February 2013 edition of the Central Coast ARC "Smoke Signals" magazine, reflects practical experience. This documentation offers a field-deployable 40-meter loop antenna solution, utilizing readily available components like fiberglass squid poles. It presents a practical approach for operators seeking a robust, portable antenna for the 40-meter band, emphasizing simplicity and efficiency in its design and deployment.

Learn how to build a simple transmitter called the 'Easy Ten' that can be easily heard at a distance of 10 miles using a random length wire antenna thrown into a tree. This article focuses on working with frequencies in the 3.5 and 7 MHz range without the need for complex setups like coax lines or baluns. The author shares their experience of making contacts across the Pacific Ocean and the United States using just one watt of output power and simple antennas. Discover how to optimize signal output using a homemade level meter made from a DC microameter and a germanium diode.

W1JR-style common mode chokes are versatile tools for antenna experimentation. Three variants were constructed using RK4 ferrite cores and RG303 Teflon coax, differing only in output terminals: banana connectors for dipoles, N-connectors for antennas with existing terminals, and bolts with washers for vertical antennas. Materials included junction boxes, terminals, and small hardware. Assembly involves maximizing windings on the core, securing with ties, and gluing components. Improvements included switching to multi-stranded wire for durability. These chokes provide efficient, customizable solutions for various antenna setups.

The blog and website of English amateur radio operator G0RIF, located near Lichfield in central England. Favourite aspects of the hobby are DXing, RTTY, portable operating and experimenting with wire antennas.

This article explores Beverage antennas, a type used for low-frequency radio reception. Despite the mystique, they are relatively simple wire antennas placed near the ground. Their key benefit is improved signal-to-noise ratio by rejecting unwanted signals. While lengthier antennas offer better reception, even shorter versions (around 200 feet) can improve DX reception compared to traditional antennas.

VE1ZAC's analysis details the performance of **MFJ927** and **SGC239** autotuners with portable HF vertical antennas, specifically comparing 31 ft and 43 ft configurations. The resource originated from challenges encountered during a Maritime QSO Party roving operation, necessitating a lightweight and easily deployable antenna system. Target bands for the contest included 80, 40, 20, 15, and 10 meters, with a maximum power handling of 100 W CW. The author utilized a 30-foot carbon fiber push-up pole to support a vertical wire element, noting its 2 lb weight and reliability. EZNEC modeling was employed to predict performance, showing favorable results for a 30-foot vertical with elevated radials, particularly on 40 and 20 meters. Feedpoint impedance measurements, taken with an AIM4170C, are presented for various HF bands, both with and without a 41-foot RG6 stub designed to reduce reactance on 80 and 20 meters. The stub significantly improved matching on these bands, easing the tuner's workload. Operational tests revealed issues with the MFJ927's reliability during contest setup, leading to reliance on the K3's internal tuner. The SGC239, tested post-contest, performed flawlessly. A detailed side-by-side comparison covers mechanical aspects, connection options, power bias, impedance range, board quality, and documentation. Modifications to the MFJ927, including a new aluminum case, white paint for heat reduction, and upgraded impedance-measuring resistors, are also described.

This FAQ covers building and buying transformers for loop-on-ground and Beverage antennas. Building one uses ferrite cores and thin wire. Buying is an option, with the DX Engineering BFS-1 being recommended. These transformers isolate the antenna from the cable to prevent unwanted signal pickup.

Details the construction and performance of a phase-controlled receiving array, specifically a **MicroSWA** variant, optimized for QRP low band fox hunting on 40M and 80M. The resource documents the author's iterative design process, addressing significant regional noise challenges encountered during 0100-0230 UTC fox hunt periods. Initial experiments involved a director wire on a 40M vertical, yielding limited improvement, prompting a shift towards advanced null-steering techniques. The project leverages concepts from Victor Misek’s "The Beverage Antenna Handbook" and Dallas Lankford’s extensive work on phased receiving antennas for urban lots. A key modification involved integrating a new passive phase control box and a push-pull **Norton common base preamp** using 2N5109 transistors, designed for high third-order intercept performance to maintain weak signal integrity amidst strong adjacent signals. The system incorporates Faraday-shielded transformers with RG174 primaries on -75 ferrite cores, housed in ABS plastic pipe. Performance tests confirmed the MicroSWA's ability to produce deep, steerable nulls, achieving approximately 30 dB noise reduction on 160M, 80M, and 40M. This enabled detection of QRP signals undetectable on conventional transmit antennas. The final unit includes front panel controls, a 10-11 dB preamp, and a robust power conditioner, demonstrating effective noise mitigation for challenging low band QRP operations.

The article describes adding lightning protection to Beverage antennas, which are long wires susceptible to lightning strikes. The author reviews common lightning protection circuits and discusses their components. They then detail their design based on existing methods, highlighting choices for components and reasoning behind them. Finally, the author presents the completed design and its implementation on their Beverage antennas.

Early 20th-century transatlantic wireless communication efforts involved distinct technical approaches by Reginald Fessenden and Guglielmo Marconi. Marconi's systems, operational until approximately 1912, primarily utilized _spark technology_ for wireless telegraphy, facilitating Morse code communication between ships and across oceans. His Poldhu station in December 1901 radiated signals in the MF band around 850 kHz, later evolving to 272 kHz in October 1902, and eventually 45 kHz by late 1907 with increasingly larger antenna structures like the pyramidal monopole and capacitive top-loaded arrays. Fessenden, conversely, focused on _continuous wave transmission_ for wireless telephony, recognizing its necessity for speech. His transatlantic experiments in 1906 employed synchronous rotary-spark-gap transmitters and 420-foot umbrella top-loaded antennas at Brant Rock, MA, and Machrihanish, Scotland, tuned to approximately 80 kHz. Fessenden later utilized the _Alexanderson HF alternator_ at 75 kHz by late 1906 for pure CW transmission, integrating a carbon microphone for amplitude modulation. Receiver technology also differed, with Marconi initially relying on untuned coherer-type detectors, later developing the magnetic detector in 1902, while Fessenden's CW approach necessitated more advanced detection methods.