Search results

The article describes a high-gain, compact beam antenna design for the 2-meter band (144-146 MHz). The NSH 4x4 Boomer is a 4-element antenna that is mounted on a 4-foot boom with an 8.2 dB gain, 1.2:1 SWR, and a front-to-back ratio of 18 db. It is designed for mobile operations and little area, making it perfect for field usage such as disaster management. The design employs regularly spaced parts with a straightforward gamma match for tuning, and the construction materials include a square boom and polished aluminum tubes. In local and portable tests, the antenna worked regularly, achieving contact distances of up to 15 kilometers.

The 20-10 meter fan dipole antenna described here offers broadside East/West coverage, a characteristic I've found particularly useful for working DX across the Atlantic and Pacific from my QTH. This design connects multiple dipoles of varying lengths in parallel at a single feedpoint, enabling operation across 20, 17, 15, 12, and 10 meters without the need for an external antenna tuner or switching. The guide specifies element lengths for each band, constructed using 1/2 inch PVC pipe for the elements and a 2-inch PVC pipe for the 8-inch long feedpoint connector, ensuring a robust build. Key advantages highlighted include its multi-band coverage, simplified installation, cost-effectiveness, and improved efficiency compared to single-band alternatives. The antenna is horizontally polarized when deployed at a height of 50 feet, providing a favorable radiation pattern for long-haul contacts. Materials required are readily available, including PVC pipes, _RG-8X_ feedline, antenna wire, and guying rope, making it an accessible project for most hams. This _fan dipole_ project provides practical considerations for construction and tuning, aiming for optimal SWR performance across the target bands. The detailed instructions, coupled with the specified components, allow for a straightforward build, even for those with limited antenna building experience, yielding a capable HF antenna for the upper bands.

The ICOM IC-705, a popular QRP transceiver for portable operations, often presents unique challenges for field deployment. This resource details practical solutions for common portable setup issues, particularly for _Parks on the Air_ (POTA) activations. It describes a custom bracket for connecting antennas to the IC-705 through a backpack's antenna flap, utilizing a BNC female-to-female chassis mount connector to mitigate cable tangles. The author shares experiences with a DIY magnetic loop antenna, noting its ease of tuning with the IC-705 and successful CW contacts on 40 and 20 meters over distances exceeding **1000 miles**. Another modification presented is a strain relief solution for the microphone cord, replacing the standard spring clip with an easier-to-attach method. The page also mentions using a _Wolf River Parks antenna_ for POTA activations and references the QRPGuys DS-1 antenna as another portable option. Firmware updates and integration with an LDG Z11-Pro II auto-tuner are also discussed.

The LKJ Wednesday Night Special Antenna, designed by John Whiteman K5LKJ, is a compact 50-foot coil-loaded dipole for 80-meter operation, ideal for space-limited hams in residential areas. Using two 1-inch diameter PVC coils with 87 turns of #16 magnet wire each—placed 10 feet from the center—it tunes to 3.910 MHz for local nets like BVARC Rag Chew. Constructed with #14 wire, ceramic insulators, and Mini-8X feedline, it handles 1000W, performs well at low heights for NVIS, and requires a tuner for bandwidth. Collaborative tuning by club members ensured success.

Discover how to easily listen to amateur radio bands with insights from Frank SWL, an experienced radio enthusiast. This guide covers essential tips for tuning into frequencies between 10 meters and 160 meters using modern tools like Web SDR and Kiwi SDR. Learn about identifying callsigns, understanding Q codes, and optimizing your antenna setup for better reception. Whether you're a beginner or an experienced listener, this article provides practical advice for enhancing your radio listening experience in 2025.

This page discusses the construction and design of a shortened 2-element Yagi antenna for the 40-meter band, focusing on the driven element. The author shares insights on adding hats to the coil to reduce losses and improve performance. The article also mentions the use of EZNEC modeling software and an AIM4170 analyzer for tuning. Amateur radio operators interested in such antenna design and optimization for the 40-meter band can find useful information and practical tips on this page.

Effective suppression of harmonics and parasitic radiation from HF transmitters is crucial, especially with the increasing sensitivity of VHF/UHF radio channels to interference. This project details a hybrid low-pass filter (LPF) designed to operate across the HF bands up to 51 MHz, making it suitable for 6-meter band operations while providing deep VHF/UHF suppression. The design addresses the challenge of modern interference landscapes, where even microvolt-level signals can disrupt wireless sensors and other simple VHF/UHF receivers. The filter utilizes a single elliptic link, combining high cutoff steepness with robust suppression in the hundreds of megahertz range. A key feature is the use of only two standard capacitor values, simplifying construction and component sourcing. The article provides a detailed schematic, performance characteristics, and _RFSim99_ model file, demonstrating a reflection coefficient S11 below 0.017 (VSWR < 1.03) across 1-51 MHz, ensuring minimal degradation to the antenna system. Construction notes include coil winding specifications and capacitor selection guidance, with recommendations for _FR-4_ assembly. Two capacitor sets are presented, with the first variant recommended for its lower RF current demands, keeping currents below 3 A at 1 kW passing power at 51 MHz. Fine-tuning involves adjusting frameless coils, with considerations for capacitor tolerance and high-frequency capacitance measurement accuracy.

Details the installation and operation of the DX Engineering TFS Series Transmit Four Square System Phasing Units, specifically models like the DXE-TFS4-160B, DXE-TFS4-80B, and DXE-TFS4-40B. It covers system components, required parts, and a discussion of vertical antenna selection, including a table of suitable DX Engineering Monoband Vertical Antennas. Installation procedures are outlined, encompassing site selection, four square layout, topographical considerations, and noise source mitigation. Specific instructions are provided for mounting the phasing unit, antenna feedline connections using 1/4-wave 75-ohm coaxial cables, and control wire routing. The document also includes details on radial system implementation, with a table of radial wire lengths for 160, 80, 75, and 40 meters, and procedures for tuning the vertical antennas for optimal performance. Operational aspects of the Four Square Control Console are described, including front and rear panel functions, control logic (Table 4), and typical transceiver/amplifier interconnections. The system enables directional control with approximately 5 dB gain over a single vertical element in four directions or an omni-directional pattern, achieving typical front-to-back ratios exceeding 20 dB. Lightning protection and initial system testing are also addressed, along with a 5 kW CW and 10 kW PEP SSB power rating and hot switching lockout feature.

Demonstrates the construction of an active loop converter specifically designed for the Low Frequency (LF) bands, addressing common localized noise interference in LF reception. The design integrates a sharply tuned circuit and a tuned loop antenna, utilizing the loop as the sole tuned inductive element. By applying positive feedback, the converter significantly increases the loop's effective Q, achieving factors between 1000 and 2000, which sharpens tuning and reduces noise. The circuit employs an _NE602_ mixer stage, feeding its output to an HF receiver, with a crystal-locked local oscillator at 4 MHz. A 20-turn, 0.8-meter square loop antenna with 500 uH inductance is detailed, connected via 2 meters of figure 8 flex cable. The converter offers three selectable frequency bands: 195-490 kHz, 150-220 kHz (including the New Zealand amateur band), and 128-160 kHz (covering the European amateur band). Performance measurements indicate an effective 3dB bandwidth of approximately 100 to 200 hertz at 200 kHz. The article provides insights into component selection, including an _LF353_ op-amp and a trifilar wound transformer on a ferrite core. Sensitivity figures are presented, showing 7.5 uV of converted output per 1 uV/meter signal strength into a 50-ohm load, or 37.5 uV into an _FRG7_ receiver, highlighting its capability to extract weak signals from noise.

A full-wave delta loop antenna, approximately 141 feet in total wire length for the 40-meter band, offers a low angle of radiation, which is highly advantageous for DX operations. This design, optimized for both 30m and 40m, leverages a specific circumference calculation of 1005/F, ensuring resonance on both bands through a simple switching mechanism. The antenna's configuration enhances long-distance communication, making it a practical choice for hams with limited space. The resource details the construction process, including the use of a _Ceramic Knife Switch_ for band selection and an _RG-11_ matching section to achieve optimal impedance. It outlines the precise loop lengths required for each band, along with tuning secrets to ensure efficient operation. Requiring a minimum height of 12 feet, this antenna can be supported by a single mast or tree limb, making it suitable for suburban installations where stealth or space constraints are a factor.

The RXC70/10 is a sensitive 70 MHz to 10-meterband converter using the Philips SA602 mixer IC. It operates with high stability and low noise, converting 70–72 MHz signals to 28–30 MHz for general coverage receivers. The compact, low-power design (15mA) supports various modulations and uses. Its versatility makes it suitable for amateur radio applications with proper tuning and antenna setup.

This article details an Inverted-L antenna design optimized for 160-meter band operation, consisting of a 10m vertical section and a 28m horizontal section supported by Spiderpoles. Despite its relatively low height compared to the wavelength, the antenna has demonstrated impressive DX capabilities, achieving contacts up to 3,453 miles into Asiatic Russia. The system incorporates a Pi-Network ATU at the base for tuning flexibility. While modeling shows a radiation pattern favoring the South, practical operation indicates effective all-round coverage on Top Band.

Twenty 1-watt carbon film resistors are configured in parallel to construct a 50-ohm **dummy load** for amateur radio applications. The design incorporates a heatsink for thermal dissipation and an **SO-239 connector** for RF input, making it suitable for QRP operations. This budget-friendly project details component selection, soldering techniques, and mounting procedures, achieving a continuous power rating of 10 watts and intermittent handling of up to 100 watts across HF and VHF frequency ranges. The resource provides a step-by-step guide for assembly. This construction offers an economical solution for essential shack tasks such as antenna tuning, transmitter testing, and SWR meter calibration without radiating an RF signal. The utilization of readily available components significantly reduces the overall build cost compared to commercial alternatives, providing radio amateurs with a functional and reliable test accessory. While specific VSWR measurements are not provided, the design prioritizes practical utility for low-power transceiver diagnostics and general RF experimentation.

The 4m Slim Jim antenna project provides a construction guide for a low-cost, high-performance aerial designed specifically for the 70 MHz FM band. This design achieves a 1:1 SWR across the 4m FM band with straightforward adjustment of the feed point, utilizing RG-58 coax. Its low angle of radiation contributes to effective signal propagation. Construction involves using plastic knitting needles as spreaders and a telescopic fishing pole for support, with components secured using two-part epoxy. Annealed bare single-core copper wire forms the radiating element. The setup process includes raising the antenna at least 3 meters above ground for tuning, adjusting the RG-58 feed point for optimal SWR, and then soldering connections. Waterproofing is achieved with yacht varnish. The design emphasizes low wind resistance for durability, making it suitable for exposed outdoor installations. A PDF construction diagram is available to supplement the written instructions.