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Demonstrates the construction of a **multi-band HF mobile antenna** utilizing a modified CB whip antenna base. The resource details the process of stripping a commercial CB whip, winding a new helical coil with 0.7mm insulated copper wire, and identifying tapping points for various HF bands. It emphasizes the importance of a rugged, slim design for mobile operation, discussing mechanical length, power handling (up to 200 watts), and coil diameter considerations. The article includes a graphic illustrating the antenna's operational principle, where sections of the helical coil are shorted from bottom to top to maintain efficiency and high Q. The resource presents a practical approach to achieving **band switching** without an external tuner, by manually adjusting tapping points on the coil. It provides a table with reference lengths in centimeters from the feedpoint for 7 MHz (40m) through 28.7 MHz (10m), including WARC bands. The author details mounting techniques, suggesting a Diamond bracket for secure attachment to a vehicle trunk, and stresses the critical role of proper grounding for optimal performance. The design allows for operation on 75m and 80m bands by adding a 110mm steel whip.

The G5RV antenna, with an overall length of **31.10m (102ft)**, functions as a 3/2-wave on 20 meters when installed horizontally at 12m (39ft), exhibiting a resonant frequency of 14.150MHz and an approximate resistance of 80 ohms. Its 10.36m (34ft) stub line, designed as a 1/2-wave on 14.150MHz with a 0.97 velocity coefficient, acts as an impedance transformer across other bands, aiming for multiband operation without traps. On 20m and higher frequencies, the G5RV demonstrates improved gain compared to a standard dipole, attributed to the _collinear effect_ from multiple 1/2-waves along the wire. The original design sought a multiband solution for limited spaces, often requiring an Antenna Tuning Unit (ATU) for effective operation across bands like 80, 40, 30, and 20m, particularly with modern solid-state PAs. Variants, such as the F8CI modification, incorporate a 1/4 current balun at the stub line's base for symmetrical-to-asymmetrical transition, known as a _remote balun_. Proper flat-top or inverted-V installation is critical for maintaining symmetry and collinear gain, with inverted-V apex angles below 120° progressively diminishing higher-band performance.

Details the construction of a **multiband vertical** antenna, specifically designed for stealth operation in a rented property, covering 80m, 60m, 40m, and 30m. The author, N3OX, leverages a 12m Spiderbeam telescoping fiberglass pole as the primary support, noting its sturdiness compared to typical fishing rods while remaining light enough for quick deployment and takedown. The radiating element is a 14 gauge Flex-Weave wire, attached to the pole's top with a rubber grommet, and fed by 27 bare 18 gauge radials spread across a 40-foot square backyard. N3OX describes the impedance matching solution, opting for custom-built L-networks over a remote tuner to enable fast bandswitching. Using an MFJ-259B and EZNEC modeling, base impedances were measured and component values calculated with G4FGQ's L_TUNER and SOLNOID_3 programs. The 80m coil is wound on a 3.5-inch PVC form, while the 30m, 40m, and 60m coils are air-wound, self-supporting #10 wire. Variable capacitors are incorporated for 40m and 30m shunt elements, with the 60m impedance matched by a series inductor. The project includes a **servo-controlled** homebrew band switch, utilizing a two-pole 12-position ceramic wafer switch for remote operation, addressing the limited 80m bandwidth. The entire matching network is housed in a weather-resistant shelter constructed from lumber and aluminum flashing. N3OX reports good DX results at 100W, estimating the total cost between $150 and $250, depending on existing parts.

The **Extended Double Zepp** (EDZ) antenna, a simple wire design, is presented as a means to achieve 3-4 dB of gain on 10 meters, with an overall length of just 43 feet. This resource, authored by WB3HUZ, details several gain antennas suitable for the 29 MHz AM segment, all modeled using EZNEC software at 30 feet above ground. Other designs include a compact rectangular loop, offering more gain than the EDZ and a lower take-off angle, and the **Lazy H**, a bidirectional antenna providing 6 dB gain, which is also workable on 20, 17, 15, and 12 meters. The Bisquare, a diamond-shaped open-top loop, is also featured, providing approximately 4 dB gain and requiring only a single support. These designs are primarily fed with ladder line or open-wire line to simplify matching, though a coax feed option for the EDZ is shown for 10-meter-only operation. The Lazy H, for instance, requires about 16 feet of open-wire line for its half-wavelength elements spaced a half-wavelength apart. An enhanced EDZ Lazy H variant is also discussed, achieving an additional 1-2 dB gain by extending element length to 1.28 wavelengths and increasing spacing to 0.64-0.75 wavelengths. The Bisquare, while primarily a 10-meter antenna, can be adapted for 20 meters by closing the top connection.

Presents the KE4UYP linear-loaded vertical antenna design, which introduces very little loss on 80 or 160 meters, achieving an overall radiation efficiency of 80% to 85%. This design addresses common pitfalls of traditional base-fed verticals by placing the majority of the current at the top of the antenna, eliminating the heavy reliance on extensive ground radial systems. The author's initial 10-meter model, only three feet tall, yielded 5/9 signal reports to Anchorage, AK, and Europe, confirming its effectiveness. The antenna incorporates both vertically and horizontally polarized radiators, with a 1/4 wavelength horizontal counterpoise located at the feed-point, near the top, to create an almost totally omnidirectional pattern with high wave angle horizontally polarized radiation. This dual polarization ensures even illumination across all take-off angles, making it effective for both local contacts and **DXing**. The vertical element is linear loaded, adding capacitance reactance and making it longer than the horizontal element to achieve resonance and raise the feed-point impedance to 50 ohms. Fine-tuning the antenna requires careful adjustment, as tower reactance can vary. The article suggests starting with 80 feet for 80m and 170 feet for 160m for the vertical wire, then trimming for resonance. Bandwidth specifications include 300 kHz under 2:1 **SWR** on 80m and 100 kHz on 160m when suspended between trees, or 150 kHz on 80m when side-mounted on a tower.

The Flower Pot Antenna project details a portable dual-band antenna primarily operating on 10 meters, with secondary resonance near the 30-meter band. Construction involves winding RG58 coaxial cable uniformly around a large plastic flower pot, approximately 70cm high with a 60cm top diameter. The design eliminates the need for radials, contributing to its compact and lightweight nature. Key construction steps include soldering the inner conductor to the shield at one end of the wound cable and connecting the wound cable's shield to the rig cable's inner conductor at the base. An LC network, comprising a variable capacitor (0-200pF) and an inductor (10 coils, 5cm diameter, 2mm wire), is inserted between the wound cable's inner conductor and the rig cable's shield. Tuning is performed with an antenna analyzer, adjusting cable length and the variable capacitor for optimal impedance on 10 meters. The antenna performs effectively when installed horizontally.

This is a combination center and top loaded multiband antenna by Mark D. Lowell, N1LO PDF File

This drawing shows a simple 10 meter wire J-pole antenna designed for 28.4 MHz. It is a vertical, end-fed Zepp-style antenna made from common materials and intended for easy home construction. The main radiating element is a straight length of stranded copper wire, either 14 or 18 gauge, cut to about 16.5 feet. At the top, the wire is supported by an insulator, allowing the antenna to be hoisted vertically. The matching section is made from 450-ohm ladder line, approximately 7 feet 9.5 inches long, and shorted at the bottom. This matching stub transforms the impedance so the antenna can be fed with coaxial cable. The feed point is tapped about 6 inches above the bottom of the stub, with the shield and center conductor connected at the proper points. A choke balun is formed with five turns of RG-58 coax in a 4-inch diameter loop to help reduce unwanted RF on the feed line. The drawing notes that this antenna has about 0 dBd gain, similar to a dipole, but offers an omnidirectional pattern and low-angle radiation when installed high. Its main advantage is practical performance, simple construction, and effective coverage for 10 meter operation.

Multi-band centre-fed antenna capable of very efficient operation on all HF bands, specifically designed with dimensions which allow it to be installed in gardens and other open spaces which accommodate a reasonably-straight run of 31.1m (102 ft) for the flat-top standard model.

Interesting article on mobile antennas by Cebik. . The article offers advice for setting up and operating mobile antennas for ham radio use. It emphasizes the lossy nature of mobile-in-motion antennas but encourages users to rise to the challenge. Steps include safeguarding car electronics, choosing proper cabling, and carefully selecting and mounting antennas. It highlights potential issues like roof mounting, trunk lip grounding, and side-mounting for trucks. For stationary operation, options like dipoles or beams are explored, with safety tips for masts and guying systems. Lastly, it stresses safety, suggesting stopping the vehicle to operate whenever possible

A half sloper antenna for 160 meter band Italian translation of a WD8DSB article appeared in a QST issue during 1998. This article presents a **Reduced-Size Half Sloper Antenna for 160 Meters**, designed for amateur radio operators with limited space. By utilizing a 40-foot tower or a tree, you can build an efficient antenna that slopes down, achieving a 2:1 SWR bandwidth of 120 kHz. This innovative design allows for effective communication on the "Top Band," making it ideal for winter DXing.

The ZS6BKW multiband HF antenna, a design by ZS6BKW (G0GSF), functions effectively on multiple HF bands without requiring an Antenna Tuning Unit (ATU) for 40, 20, 17, 12, 10, and 6 meters. This antenna, approximately **27.51 meters** (90 feet) long with a 12.2-meter (40-foot) open-wire feeder, is a direct descendant of the _G5RV_ but offers superior multi-band resonance. It can be deployed as a horizontal dipole or an inverted-vee, with the latter requiring only a single support and maintaining an apex angle of at least 90 degrees to prevent signal cancellation. Performance data, recorded with an MFJ Antenna Analyser, indicates SWR values of 1:1 on 7.00 MHz (40m) and 14.06 MHz (20m), with SWR below 1.3:1 on 17m, 10m, and 6m. While primarily designed for these bands, the antenna can be adapted for 80m, 30m, and 15m with an ATU, preferably at the balanced feeder's base. The use of 450-ohm twin-lead for the feeder is recommended over 300-ohm for improved strength and reduced losses, especially in adverse weather conditions. This design, originally published in _RadCom_ in 1993 and featured in Pat Hawker’s "Antenna Topics," provides a compact and efficient solution for HF operation, particularly for those with limited space or resources.

Presents G0GSF Brian's ZS6BKW antenna, a refined iteration of the classic G5RV, offering improved performance across multiple HF bands. The design emphasizes specific radiator and ladder line lengths to achieve lower SWR on 40m, 20m, 17m, 12m, and 10m, making it a practical choice for operators seeking a single wire antenna solution. The document includes critical dimensions for the flat-top and the 450-ohm ladder line section, which are key to its multiband resonance characteristics. Unlike the original G5RV, the ZS6BKW aims for direct 50-ohm feedpoint impedance on several bands, reducing the need for an external antenna tuner. My field experience with similar optimized dipoles confirms that precise construction, particularly the ladder line length, is paramount for realizing the intended SWR benefits. This design offers a compelling alternative for hams with limited space or those preferring a less complex antenna system.

This resource details the computer-optimized design of the _ZS6BKW_ multiband dipole, an evolution of the classic _G5RV_ antenna. It begins by referencing the original 1958 RSGB Bulletin article by Louis Varney G5RV, explaining the operational principles of the G5RV's flat-top and open-wire feedline on 20m and 40m, noting its impedance transformation characteristics for valve amplifiers of that era. The article then transitions to the rationale for optimizing the design for contemporary solid-state transceivers requiring a 50 Ohm match. The core of the project involves using computer modeling to determine optimal lengths for the flat-top and matching section, aiming for a VSWR of less than 2:1 on multiple HF bands. It discusses the process of calculating feedpoint impedance based on antenna length and frequency, referencing professional literature from Professor R.W.P. King at Harvard University. The analysis also considers the characteristic impedance (Z(O)) of the open-wire line, identifying a broad peak of adequate values between 275 and 400 Ohms. Specific design parameters for the improved ZS6BKW are presented, including a shorter flat-top and a longer matching section compared to the original G5RV, with a velocity factor of 0.85 for the 300 Ohm tape. The article confirms acceptable matches on 7, 14, 18, 24, and 28 MHz bands when erected horizontally at 13m, and also discusses performance in an inverted-V configuration, noting frequency shifts. The author, Brian Austin ZS6BKW, emphasizes the antenna's suitability for modern 50 Ohm coaxial cable without a balun.

The ZS6BKW wire antenna, a variant of the G5RV, utilizes a specific 13m (42.6 ft) length of 450-ohm window line as its matching section, feeding a 28.5m (93.5 ft) flat-top element. This design aims for lower SWR on 40m, 20m, 17m, 12m, and 10m compared to a standard G5RV, often achieving SWR values below 1.5:1 on these bands without an antenna tuner. The feedpoint impedance transformation provided by the window line allows for direct connection to 50-ohm coax on multiple bands. F4FHH's experience involved constructing the ZS6BKW and evaluating its performance against an _OCF dipole_ (Off-Center Fed) on various HF frequencies. The article includes observations on SWR readings and operational effectiveness, highlighting the ZS6BKW's suitability for multi-band operation. The antenna's overall length, including the flat-top and window line, is approximately **41.5 meters** (136 feet), making it a significant wire antenna for fixed station use. Comparative analysis with the OCF dipole provided practical insights into the ZS6BKW's advantages and limitations, particularly concerning bandwidth and tuner requirements.

A project for a balcony antenna that works on 7 10 14 MHz made by 2 PVC tubes coiled with insulated copper wire, a solution for restricted lots.

A _Topfkreis_ antenna, also known as a "bicycle pump" antenna, is presented as a simple vertical design for the 70 cm band. This variant of the J-pole antenna is notable for not requiring a ground plane, simplifying deployment. The construction details specify using aluminum tubing for the radiating element, with precise measurements for the quarter-wavelength outer tube (32 mm diameter) and the three-quarter wavelength inner sliding tubes (10 mm and 8 mm). Feeding is via a 50-ohm coaxial cable connected 90 mm from the base of the central tube. This design can achieve a gain of **4 to 6 dB** when properly tuned using the adjustable radiating element. The article details the fabrication of a critical aluminum washer, suggesting a method using a hole saw and a drill press as a lathe for precise adjustment. The illustrated example is specifically for the 70-centimeter band, and the author, Pop, clarifies construction points in the comments, including material choices and assembly techniques, ensuring a robust build for VHF/UHF operation.

A 90-foot vertical antenna constructed from **aluminum irrigation tubing** is detailed, focusing on its innovative raising and lowering mechanism. The resource describes a **45-foot ginpole** system, allowing a single operator to erect or lower the antenna in minutes. It covers the mechanical design, including the pivot base, insulated joints for the tubing sections, and guy wire attachment points. The antenna consists of two 30-foot sections of 4-inch tubing and one 30-foot section of 2-inch tubing, stacked with the smaller diameter at the top. The electrical design incorporates PVC "condulet" boxes at the 30-foot and 60-foot points, housing relays to change the effective height for multi-band operation on 160, 80, 40, and 30 meters. Ferrite rod inductive chokes are used for DC control and to tune out gap capacitance. The antenna is fed with 1000 feet of open wire line, connected to a matching transformer comprising stacked toroids and a coaxial/toroidal balun. Grounding is achieved with a 3x3 foot grid of 16-gauge tinned copper wires with soldered crossovers.

A 100Ft wire antenna for the top meter band

The G5RV multiband HF antenna, designed by Louis Varney (G5RV) in 1946, is a popular compromise antenna offering good overall performance on most HF bands when paired with an external antenna tuner. The basic full-size G5RV measures 102 feet across the top for 80 through 10 meter operation and is fed at the center via a 34-foot low-loss feed-stub. This interaction between the radiating section and the feed-stub facilitates matching across 80-10 meters with a standard tuner, often eliminating the need for ladder line directly to the shack. The antenna's design center frequency is 14.150 MHz, configured as a 3/2-wave dipole on 20 meters, with its 102-foot length derived from long-wire antenna formulas. Construction details emphasize the matching section, which can be open wire, ladder line (window-type), or TV twin lead. Each type has a specific velocity factor (VF) affecting its physical length for an electrical half-wave on 14 MHz; for instance, open wire requires 33.7 feet (VF 0.97), ladder line 31.3 feet (VF 0.90), and TV twin lead 28.5 feet (VF 0.82). The article provides formulas for calculating these lengths and discusses the antenna's behavior on individual bands, from 3.5 MHz where it acts as a shortened dipole, to 28 MHz where it functions as two three-half-wave long-wire antennas fed in-phase. Practical construction notes include recommendations for vertical descent of the matching section, sealing the coax junction, providing strain relief, and winding a coaxial choke coil to mitigate common mode current. The resource also presents dimensions for double-size (204 ft) and half-size (51 ft) G5RV versions, along with their corresponding matching section lengths for various line types, making it a versatile reference for hams considering this classic wire antenna.

The _National Contest Journal_ (NCJ) serves as a dedicated resource for amateur radio contesters, providing in-depth articles, operational strategies, and technical insights. Published bimonthly by the ARRL, it covers a wide array of contesting topics, including antenna systems, station optimization, operating techniques, and rule interpretations for major events like the NA Sprint and various QSO Parties. The journal aims to enhance the competitive edge of participants across all skill levels, from casual operators to serious multi-operator teams, by sharing experiences and data from high-scoring stations. NCJ content frequently includes detailed analyses of contest results, offering breakdowns of scores, participant statistics, and comparisons of operating strategies. Readers can find practical advice on improving their contest performance, such as optimizing logging software usage or maximizing **run rates**. The journal also features columns on specific contest modes like RTTY and provides updates on rule changes and upcoming events, helping contesters prepare for future competitions and achieve better results, often leading to **top 10** finishes in their respective categories.

A 4 element addition for 10m to an existing 4 element yagi (ZX antennas)

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.

Demonstrates various practical amateur radio projects and technical discussions through video episodes. One episode details cutting and retuning a _1/4 wave shorted stub_ from 101.7 MHz to 107.5 MHz to safeguard a transmitter's driver stage, alongside insights into advanced _160-meter antenna systems_ like eight-circle arrays and beverage antennas. Another segment covers upgrading firmware on an _ATS-20+_ receiver using AverDudes for improved display and functionality, and a detailed guide on using D-Star DR mode on an _ICOM ID-52A_ for international repeater programming. Additional content includes a deep dive into _OpenHamClock_ as a potential replacement for the HamClock project, updates on _Raspberry Pi 5_ running Trixie OS, and a review of the Choyong LC90 Internet radio with AI integration. The series also features "Ham College" episodes, which meticulously prepare viewers for the Technician Exam by covering topics such as antenna and transmission line measurements, SWR interpretation, and the functions of basic electronic components like rectifiers, relays, and transistors. Practical advice on coaxial cable characteristics, dummy loads, and proper soldering techniques is also provided.

Antenna for limited space, made from 24AWG wire helically wrapped around the top element of a 3-element cane pole, is basically a fully-loaded vertical and performance are limited and should represent the last resort for extreme cases.

The **136kHz Vertical Antenna** at G3YMC employs a Butternut HF2V structure, standing 10m tall. It integrates a 6.5mH loading coil to achieve resonance, with a matching transformer for impedance adjustment. The antenna's configuration includes top loading via a 12m horizontal wire, enhancing capacitive impedance. Initial measurements indicated a high impedance of around 300 ohms, necessitating a transformer for a 50-ohm match. Despite challenges with ground losses, the vertical antenna has shown improved performance in specific directions, filling nulls present in the previous loop antenna setup. The tuning remains broad, with variations due to environmental factors affecting the matching. Ongoing adjustments and comparisons with the loop antenna will continue to refine its effectiveness.

Refurbishing my 10 years old Cushcraft A3S triband HF Antenna

KB9AMG's Top WSPR Spots presents a focused online tool for monitoring **2-way WSPR reports**, specifically detailing propagation data from February 2026 through March 2026. This resource aggregates _WSPRnet_ data, allowing radio amateurs to observe weak signal propagation conditions across various bands. The interface is straightforward, presenting callsigns, frequencies, signal-to-noise ratios, and distances for each reported contact, which is crucial for understanding current band openings and signal paths. The utility of this WSPR spotter lies in its ability to quickly visualize global propagation. Users can identify active stations and assess signal viability over long distances, with reports often showing contacts spanning thousands of kilometers. For instance, a typical WSPR report might indicate a signal from Europe reaching North America with a _SNR_ of -25 dB, demonstrating effective low-power communication. This data is invaluable for planning DX operations or evaluating antenna performance under actual propagation conditions.

SJ2W Contest Station, antenna for the 160 meter is a 39m vertical. This 160m antenna consist of 29m of WIBE tower sections with an insulated base and 10m top tube.

This simple antenna was installed on the attic. Antenna was matched with help an Automatic ATU in 40, 30, 20, 17, 15, 12 and 10 meter amateur Bands. The Antenna worked satisfactory on the above mentioned bands.

Quads beams consist of 2 1 wavelength (approximately) loops, ordinarily arranged so that one is the driven element and the other is the reflector. In this project author explains how to build a two element Quad Antenna for the 28 MHz.

High Speed Multimedia (HSMM) radio, as introduced by John Champa, K8OCL, represents a significant advancement in amateur radio's digital capabilities, moving beyond traditional keyboard modes like packet radio. This initiative, driven by ARRL's Technology Task Force, focuses on developing high-speed digital radio networks capable of up to 20 megabits per second. HSMM primarily facilitates digital voice (DV) and digital video (ADV), enabling real-time video transmission from emergency scenes to an EOC without expensive ATV gear, often requiring only a laptop, a PCMCIA card, a digital camera, and a small antenna. The working group's initial efforts concentrate on cultivating microwave skills within the amateur community to build and support portable and fixed high-speed radio-based local networking, or **RLANs**. These networks prove invaluable for RACES and ARES organizations, as well as homeland security and other emergency communications. Field Day exercises and simulated emergency tests (SETs) are encouraged to hone skills in rapid site surveys and deploying broadband HSMM microwave radio networks, with examples like linking Field Day logging stations or antenna test results at the Midwest VHF-UHF Society Picnic 2003. Getting started with HSMM often involves adapting off-the-shelf **IEEE 802.11** (WiFi) equipment to comply with amateur radio regulations, typically operating in the 2.4 GHz ISM bands. While consumer WiFi gear has range limitations under Part 15 rules, proper setup under amateur regulations can extend coverage significantly, with test networks like the Hinternet achieving 5-15 mile ranges at 54 M bit/s using small mast-mounted dish antennas. Careful selection of equipment with external antenna ports, high transmit power, and low receive sensitivity is crucial, along with using low-loss coaxial cable like LMR-400 for optimal performance at these frequencies.

Microwaves101 provides an extensive repository of information covering fundamental principles of microwave design, targeting engineers and radio amateurs interested in the higher frequency spectrum. The site features a detailed _encyclopedia_ of microwave terms and concepts, alongside practical design considerations for various components and systems. It serves as a foundational reference for understanding RF propagation, transmission lines, and active/passive microwave circuits. The resource includes numerous calculators for impedance matching, filter design, and other critical RF parameters, facilitating hands-on project development. Discussions on **10 GHz** equipment and **24 GHz** projects highlight practical amateur radio applications, extending to operations up to 134 GHz. Content spans from basic theory to advanced topics like MMIC design and antenna characteristics, supporting both educational and practical endeavors in microwave technology.

The _G3TSO_ Mobile Antenna Page details construction and tuning methods for mobile antennas operating across **10 to 160 metres**. The content describes a Hustler-based design, optimized for RF performance and vehicle speeds, featuring centre loading. For optimal operation on various bands, the loading coil placement requires clearance from the vehicle body. Antenna resonance is critical for efficient mobile operation. A mobile antenna's base impedance may be as low as 27 ohms, requiring specific matching to achieve maximum radiation, as a minimum SWR at the transmitter does not always indicate resonance or maximum output. Tuning involves physical adjustment of antenna length to achieve resonance at the operating frequency. The _G3TSO_ page outlines a tuning procedure utilizing a low-power signal source and a field strength meter to identify maximum radiation before impedance matching. Loading coil placement, either at the base, center, or top of the antenna, influences radiation efficiency and mechanical stability for mobile installations. Centre-loaded whips, such as the Hustler design, offer a compromise between efficiency and stability, often for single-band operation. Helically wound antennas, including those for **28 MHz**, may present base impedances around 17 ohms, resulting in a 3:1 SWR at resonance. Low resistance grounding at the antenna base is also specified for optimizing performance and minimizing RFI during mobile operation. DXZone Focus: Mobile | Any | Antenna Tuning | HF

Explains the fundamental purpose of a repeater, detailing how these automated relay stations overcome distance and terrain limitations for VHF/UHF communications. It traces the historical development from early Bell Telephone Labs "relay" stations in 1922 to Art Gentry, W6MEP's, pioneering K6MYK amateur radio repeater in the mid-1950s, which remains active today. The resource clarifies the distinction between simplex and duplex operation, including the unique function of a "parrot repeater" for single-frequency recording and playback. Delving into the internal workings, the guide breaks down a repeater into its core components: the antenna system, feedline (often _Heliax_ or hardline for minimal loss), duplexer, receiver, transmitter, and controller. It emphasizes the critical role of the duplexer in preventing receiver desensitization by isolating transmit and receive signals, even with distinct frequencies. The discussion highlights the importance of high-performance, durable antennas and low-loss feedlines, citing examples of equipment installed in the 1960s and 1970s that are still in perfect working order. Operating a repeater is also covered, with an explanation of frequency offset (e.g., the 600 kHz standard for 2 meters) and the function of _CTCSS_ (PL tone) for access. It outlines standard input/output offsets for various bands, from 6 meters to 23 centimeters, while noting regional variations. The guide also touches on features like autopatch and Digital Voice Recorders (DVRs), providing a solid foundation for understanding repeater technology and usage.

This blog chronicles the development of an 80-meter vertical antenna for amateur radio operation. The author constructs a top-loaded vertical using fiberglass poles, achieving significant performance improvements over their previous end-fed wire antenna. Comparative testing using the Reverse Beacon Network and on-air contacts demonstrates 8-10 dB gain on the east coast. The project evolved to include 40-meter capability through a modified design featuring a four-wire vertical cage, loading coil, and strategic guying system. Despite challenges with signal wobble during windy conditions, the vertical consistently outperforms the end-fed wire, particularly for reaching distant stations during nighttime propagation.

The Beverage we use is a DX Engineering RPS-1 dual directional 360 foot 109,7 m, oriented due North/South, six feet 1,8 m off the ground. The antenna uses 450 ohm ladder line as the antenna, and 75 ohm RG-6u for the feedline. The antenna runs atop the fence between our property and 5 acres of pasture next door.

Presents a detailed construction guide for a 9 dB, 70cm collinear antenna, utilizing readily available _RG58/U_ coaxial cable and PVC pipe for housing. The resource outlines the critical calculations for ½ wavelength sections at 444 MHz, incorporating the coaxial cable's velocity factor of 0.66, which yields a section length of 223 millimeters. It specifies the preparation and soldering of eight such half-wavelength sections, each cut to 231mm to allow for trimming, forming the core of the array. Further instructions detail the integration of a ¼ wave element (169mm #16 solid wire) at the top and a ¼ wave aluminum tube (160mm, 5/16 inch) at the bottom, crimped to the feed point's braid. The guide also addresses RF common mode current suppression by suggesting the use of _FT50-43_ toroids on the feedline. Final assembly steps cover mounting the antenna within ¾" PVC pipe using a wooden dowel, waterproofing connections, and initial SWR checks. The article also discusses scaling the design for different element counts and other VHF/UHF bands.

The article details the design and construction of a four-band Moxon beam by a radio amateur. The beam, mounted atop a rooftop tower, aimed for gain over a dipole on 20 meters, cost under $500, and included additional bands. The design features fiberglass spreaders, four bands (20/15/10/6 meters), and a single feedpoint. The construction involved computer modeling, NEC source code, and specific dimensions. The article outlines the assembly, materials, and tuning process, including in-situ adjustments for optimal performance. Despite initial challenges, the beam improved signal strength and facilitated contacts on multiple bands, marking it as the best HF antenna the author has owned.

This project details the design and construction of a Spider Quad antenna for HF bands (20m, 17m, 15m, 12m, and 10m). The boomless structure optimizes driver and reflector spacing, enhancing performance. Tuning and impedance matching were refined using antenna analyzers and a 1:2 balun. Final tests confirmed excellent SWR and gain, making this an efficient solution for top performance DXing.

This article published on QEX details measurements of tree conductivity and permittivity at HF frequencies, addressing a long-debated topic in amateur radio. N6LF conducted experimental impedance measurements on Douglas fir and maple trees using a vector network analyzer with rings of nails inserted into tree trunks. Results showed that tree conductivity increases with frequency while relative permittivity decreases, similar to soil characteristics. Measured conductivity ranged from 0.06 to 0.4 S/m at 10 MHz, aligning with values used in previous research. These findings validate that NEC modeling can reliably estimate trees' substantial impact on HF antenna performance.

The resource details the construction of a J-pole vertical antenna specifically engineered for motorcycle mounting, addressing the common issue of interference with top cases. It outlines the fabrication process, beginning with an aluminum angle bracket for secure attachment to the lateral support, followed by the creation of the antenna's base from an 8mm threaded rod bent into a U-shape, approximately **40mm** wide. The article specifies the precise method for coaxial cable connections using eyelets and 3mm screws, ensuring robust contact. Further construction steps involve fitting a 10mm aluminum tube onto the threaded rod, with a screw securing the radiating element and establishing core contact. The design prioritizes mechanical stability against vehicle vibrations over fine-tuning SWR with sliding collars. Initial testing yielded a _SWR_ of **1.2** across a significant portion of the band, with improvements noted by optimizing the coaxial braid contact point near the support bracket. The document provides practical insights into material selection and assembly, emphasizing durability for mobile operation. It concludes with aesthetic options, allowing the builder to paint the antenna or retain its natural aluminum finish, making it a functional and adaptable solution for UHF motorcycle communications.

This article presents a novel Top Loaded End-Fed Half-Wave (TLEFHW) antenna design for 20-meter ham radio operation. The antenna features a compact 14-foot vertical radiator with a capacitance hat configuration, eliminating the need for radials or ground systems. Using EZNEC modeling and field testing, the design achieves a 1.5:1 SWR across the 20m band with a 4.11 dBi gain. Key features include quick deployment, lightweight construction, and directional radiation pattern with 110-degree beamwidth. The design, while requiring a 45-foot footprint due to the top hat, offers an effective portable solution for amateur radio operators seeking a no-ground, no-tuner 20m antenna option.

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.

Detailing a Yaesu FT-857 and ATAS-120 installation in a 1997 Toyota Tacoma, the author used Polar Plot to map signal strength. Using a hand truck with a laptop, FT-817, and an Iron Horse antenna, they circled a chalk-outlined 100-foot diameter, revealing potential nulls towards the truck's rear and through the cab, offering insights into antenna performance.

TX5EU 2026 DXpedition to Raivavae Island, **OC-114**, within the Austral Islands, providing a detailed account of the German/Dutch team's operations. The resource outlines the participation of operators such as DL2AWG Guenter, PA2KW Evert, and DK2AMM Ernoe, who engaged in CW, SSB, RTTY, and various digital modes. It documents the real-world challenges encountered, including significant equipment failures and antenna damage to 80/60m, 30m, and 10m verticals due to adverse storm conditions. The page offers timely news updates on the expedition's progress, noting repairs to a power amplifier's 10/12m bandpass filter, which enabled three stations to utilize amplification. Earlier reports highlighted power failures and the loss of multiple power amplifiers, necessitating one station to operate barefoot FT-8 with 100W. The team's persistent efforts to repair antennas as weather permits are also detailed, reflecting the dynamic nature of remote island operations.