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The page provides guidance on building a mobile antenna for HF bands using a cheap CB-mobile whip antenna base. It discusses the importance of high efficiency antenna systems with a slim profile for low wind resistance, along with physical constraints and design considerations. The author shares instructions, tips on mounting the antenna, grounding, and band switching. The page includes a graphic illustrating the antenna's principle of operation and a table with reference lengths for different bands.

A large jpeg DX World map that include ITU Zones, grid squares and prefixes. This high-resolution DX World Map is an essential tool for amateur radio operators. It clearly displays ITU zones, CQ zones, grid squares (Maidenhead Locator), and DXCC prefixes, helping you to plan QSOs, track propagation paths, and participate in global contests. Whether you are a seasoned DXer or a beginner, this map provides a clear, detailed view of the radio world, improving your station's efficiency and geographic awareness. Available in JPEG format, it's perfect for display

A High Efficiency Extended Length Mobile Antenna The antenna itself is 3.42 meters or 11 feet 2 inches long from the top of the mounting spring to the tip.

Very compact and high efficiency antenna ,very low radiation angle even at low height.

Excel spreadsheet that help calculating dimensions of a high efficiency magnetic loop antenna for HF bands. Giving in input the loop perimeter, loop diameter and loop conductor will calculate electric characteristics, bandwidth, and efficiency

RF and Microwave Power Amplifier and Transmitter Technologies, amplifierlinearity, efficiency and available RF power devices.

Solartech Power Inc. manufactures, distributes and sells high efficiency solar panels and wind power turbines.

An Experimental, High-efficiency, Graphic-Tunable Magnetic Loop antenna and loop controller in a 52 pages PDF presentation with drawings and pictures

Two Delta-Loops in phase. The purpose of this article is to propose an antenna with a high gain, a high efficiency and a very low price that is easy to build for any frequency.

Iambic Keying, Debunking the Myth by Marshall G. Emm, N1FN. A keying system controls transmitter activation, ranging from basic switches to electronic keyers that generate Morse code based on paddle input. Iambic keyers, introduced in the late 1950s, respond to simultaneous paddle closures with alternating dots and dashes. Despite touted efficiency, actual benefits are modest, offering about a 5% improvement in keystrokes, diminishing at higher speeds. Iambic keying's practical value is limited and may restrict sending speeds.

Ultra High Efficiency Alternative Energy System Controllers

This article is about two excellent small helical antennas for the two meters band. With performance close to that of full sized antennas, these small helical antennas are low in profile but high in efficiency.

Hytera, a leading designer and manufacturer of professional mobile radio communication equipment, offers complete and customized communication solutions to government, public security, utility, transportation, enterprise & business for higher organizational efficiency.

High quality RF coax cables designed for ham radio use featuring high efficiency screening attenuation and transfer impedance.

F5NPV introduces a variant of the W8JK antenna design, employing the MOXON principle. With extended monopoles, it outperforms the Open-Folded W8JK, yielding a 1dbd gain improvement, enhanced performance on 30m and 10m bands, bi-directionality, and lower side attenuation. The design's focus on higher radiation impedance results in increased antenna efficiency and reduced losses. Despite these improvements, the bill of materials remains unchanged.

Not a project yet, but very theoretical thoughts about very practical amplifiers!

You can bend the wires in a half-wave dipole so that it takes up less space, with minimal loss of efficiency.It is advisable to get the ends of the antenna as high as possible, especially if children and animals are kept in the area around the antenna, as there are very high tensions on the ends of the antenna during transmission! In Norwegian

This article documents the author's journey in building, modifying, and testing a DIY short vertical antenna for 40, 30, and 20 meters, with potential 80m capability. Initially inspired by Parks On The Air (POTA), the author explores pedestrian mobile operation and details various experiments to enhance antenna performance. The piece highlights challenges, SWR tuning, portability, and practical results, emphasizing a balance between efficiency and size. Ultimately, it showcases the adaptability of DIY antennas for portable ham radio applications.

The Fuchs Antenna tuner with a resonant circuit as a coupler. The Fuch Antenna Tuner is providing a high-efficiency compare to a 49:1 transformer using ferrite . The Fuchs tuner is a resonating L/C circuit to step-up the impedance from 50 Ohm to the required 3k. The ATU is able to perform automatic tuning with the addition of a tiny Aduino Nano and a SWR bridge.

This article explores the conventional wisdom about antenna height in amateur radio operations, challenging the common belief that "higher is always better." Through practical examples and computer modeling, it examines how low-height antennas like Beverage antennas, VP2E, and End-Fed Half Wave (EFHW) configurations can perform effectively in various scenarios. The analysis includes radiation patterns and efficiency considerations for antennas at different heights, particularly focusing on portable operations. The article demonstrates that while height affects antenna performance, lower installations can still provide practical and efficient solutions for specific applications, especially in portable and QRP operations.

Antennas for low-power operation resemble those for 100W use. Minor adjustments, like capacitor voltage ratings, may apply, but basic principles persist. Portable antennas, notably Backpack Antennas for weight-conscious setups, hold relevance beyond QRP. While some antennas function acceptably at higher power, efficiency issues arise at QRP levels. Testing antennas at 100W exposes weaknesses, particularly in tuners, crucial for efficient QRP operation.

A 5/8 λ antenna, often thought to be ideal for all frequencies, has unique characteristics that don't universally apply. First introduced for medium-wave radio, it works optimally at 225° antenna length over ideal ground, yielding high efficiency. However, at VHF and higher frequencies, it offers no advantage over other antennas due to real ground conditions and complex matching requirements. DIY calculators provide only rough estimates, useful as a starting point for simulations, not for precise builds.

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.

PSKreporter.info is a highly valuable resource for amateur radio operators using digital modes. It provides real-time reception reports collected from monitoring stations worldwide, covering modes such as FT8, FT4, PSK, and others. The platform offers clear interactive maps and detailed filtering options, allowing users to analyze signal propagation, band activity, and station performance with precision. Its data is widely used to evaluate antenna efficiency, transmission coverage, and propagation trends. PSKreporter.info is easy to use, reliable, and has become a reference tool for both daily operations and technical analysis in digital amateur radio.

Single-sideband (SSB) radio enhances spectral efficiency but poses challenges with audio intelligibility, particularly in noisy conditions. A microphone audio compressor addresses these issues by dynamically managing the audio signal’s dynamic range. It amplifies quiet sounds and attenuates loud ones, ensuring consistent audio levels for improved clarity. Benefits include increased intelligibility, higher average power, and reduced spurious emissions. While essential for optimal SSB performance, careful parameter adjustment is crucial to balance natural sound quality and effective communication across various operating modes.

OM0ET manufacture high capacity variable air capacitor and tuning unit designed for Magloop antennas. OM0ET explains features and benefits of this antenna, such as easy assembly, wide frequency range, and improved efficiency. Ideal antenna setup for indoor or outdoor use, offering better QSO performance and radio listening experience. The author, identified as OM0ET, shares insights on the design and functionality of the equipment, making it a valuable antenna for portable operations.

This article discusses the Beverage antenna, a reception antenna for low bands, originally published in the Megahertz magazine between November 1990 and April 1991. It explains the challenges faced in receiving signals on low bands due to interference and how the Beverage antenna's directional radiation pattern can help improve reception of distant stations. The article highlights the importance of choosing antennas with low efficiency but sharp radiation lobes for better DX signal reception. It also compares the reception characteristics of signals from European stations versus DX stations, emphasizing the benefits of antennas favoring low arrival angles for DX signals on low bands.

This page provides a calculator to determine the total line loss and additional line loss in your transmission line based on the level of SWR. It helps hams understand the impact of high SWR on transmission line losses. The calculator allows users to input their SWR level and get accurate calculations of total losses. This tool is useful for ham radio operators looking to optimize their transmission setups and improve overall efficiency.

The FF-501DX LPF, a high-performance VHF and 10m filter, was obtained at a friend's SK sale. After becoming more active on 10m, the author reexamined the LPF and discovered it to be of high quality. The filter's efficiency was outstanding and the return loss/VSWR was better than estimated. The LPF was connected to a Bird 50R dummy load to evaluate insert loss, cutoff, attenuation over 70MHz, and return loss. The original specifications were found in an old radio magazine, along with a link to the original one-page information sheet. Comparing the results to the original specs confirms the LPF's quality.