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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 J-Pole antenna is an omnidirectional antenna that can be used for base, mobile and field day stations. It does not need a ground plane, radials or a complicated matching system. The J-Pole can be cheaply, simply and quickly constructed using a variety of techniques, some of which are discussed in this article.

Details the construction and optimization of antenna systems for amateur radio satellite operations, focusing on practical, homebrew solutions for VHF/UHF bands. It covers building _groundplane antennas_ from salvaged materials, recycling old beam antennas into new configurations like a 2-meter crossed yagi, and constructing a 10-meter horizontal delta loop. The resource also explains antenna matching techniques, including folded dipole driven elements and quarter-wave transformers, along with the importance of accurate SWR measurements and minimizing coax loss. Demonstrates how to achieve a **1:1 SWR** by carefully trimming elements and adjusting radial angles on groundplane antennas. It provides insights into selecting appropriate coax and connectors, highlighting the benefits of Belden 9913 for low loss and the proper installation of _N-connectors_. The article also addresses RFI mitigation from computer birdies and presents a design for a silent triac antenna control circuit, offering practical solutions for common satellite station challenges.

This compact 160m antenna is a half-wave dipole with a vertical section. It requires no radials and has worked well for me.

The K5OE 2-meter vertical mobile antenna design, detailed in this resource, employs a 3/8-wavelength vertical section complemented by four shortened radials, forming an off-center-fed vertical dipole. This configuration creates a self-contained lower half, enhancing efficiency compared to traditional 1/4-wave monopoles relying on vehicle bodies for a ground plane. The article specifies construction using PVC components, 10-gauge insulated wire for elements, and provides precise dimensions in both inches and centimeters for the 25-3/16" (64 cm) vertical and 7-3/16" (20 cm) radials. Performance data indicates an honest 3 dBi of gain at 6 feet elevation (2 dBi free-space), with a pattern favoring the horizon, suitable for Low Earth Orbit (LEO) satellite communications. At 20 feet high, the same antenna exhibits almost 6 dBi of gain, with a nominal 50 Ohm feedpoint impedance at 146.850 MHz. Tuning instructions involve trimming element lengths, with the author achieving a 1.2:1 SWR by pruning the mast to 24-3/4" and radials to 7". The resource highlights the antenna's effectiveness for mobile LEO satellite uplinks, particularly at low elevations, and its suitability for fixed, mobile, or portable operations. The flexible wire elements allow for easy folding, making it a practical choice for backpacking. The original design by K5OE was previously hosted on aol.com.

The basic antenna is a vertical monopole, using elevated radials to complete the ground plane by k5oe

An antenna does not have to be resonant to work, as the primary reason for resonance is to eliminate the need for an impedance-matching device. A non-resonant wire dipole fed with open-wire line and an antenna tuner can function as an effective multiband antenna. Two wires are essential for powering an antenna, ideally with a balanced configuration like a dipole fed by parallel-wire line, though coaxial cable can be used with a 1:1 balun to mitigate RF feedback on the shield. Antenna gain is achieved by shaping and aiming RF energy, concentrating it in a particular direction, as seen in beam antennas or shaped radiation patterns of wire antennas. The function of an antenna tuner is to match the transceiver's 50 Ohm output to the antenna system's impedance, which can vary widely. Wire antennas do not always require center feeding; end-fed long wires or off-center-fed dipoles (Windom antennas) can be used, often requiring a counterpoise or radial system. Dipole antennas do not need to be perfectly horizontal; their legs can be bent, inclined, or even vertical, affecting feed point impedance. Vertical antennas shorter than a half wavelength necessitate a ground system, typically comprising radial wires, with more radials generally leading to greater efficiency. A 1:1 SWR indicates an impedance match but does not guarantee a good antenna, as an inefficient antenna with a poor ground system can still show a perfect SWR while wasting RF as heat. Always using the best feed line affordable is crucial for minimizing loss and maximizing RF signal delivery to and from the antenna.

40 meter vertical antenna construction, a shortened easy-to-build vertical, with no-radials, made from surplus military camouflage poles

This resource details the four primary functions of a ground system: lightning energy dispersion, equipment safety, RF return path provision for end-fed antennas, and management of induced RF currents. It clarifies that a ground system's effectiveness varies depending on its specific function, noting that a good lightning ground might not be an effective RF ground. The content emphasizes that proper antenna system design, including baluns and appropriate feedline lengths, often negates the need for an RF station ground to mitigate common mode currents or RFI in the shack. The article quantifies lightning energy, stating its peak is in the dozens or hundreds of kilohertz, with damaging energy extending to hundreds of megahertz, and currents reaching thousands of amperes. It recommends solid, wide, smooth copper surfaces for ground leads to achieve low impedance across a wide frequency range. The author, W8JI, shares practical insights from his station, which includes two 300-ft towers and four 130-ft wire verticals, detailing his use of common point grounds and _DX Engineering RR-8 HD_ antenna switches for lightning protection without coaxial surge protectors. Specific examples of antenna systems prone to common mode current problems are listed, such as random wire antennas without proper feedline lengths and off-center fed dipoles. The text also explains how a ground screen or radial system can reduce local noise sensitivity for vertically polarized antennas by covering the lossy earth.

Ten essential tips and truisms for understanding HF antenna: Non-resonant wire dipole antennas fed with open-wire line and an antenna tuner can function effectively as multiband antennas, as detailed in "The Classic Multiband Dipole Antenna" by WB8IMY in March 2004 QST. Coaxial cable, unlike balanced parallel-wire feed lines, can cause RF to travel on the outer shield braid, leading to RF feedback to the station; a 1:1 balun at the dipole center can mitigate this by isolating the unbalanced coaxial feed line. Antenna gain is achieved by shaping and directing RF energy, with beam antennas concentrating power in a specific direction, and wire antennas also exhibiting shaped radiation patterns. An antenna tuner's primary role is to match the transceiver's 50-ohm output to the antenna system's impedance, allowing modern transceivers to deliver full power. Wire antennas do not always require center feeding; end-fed long wires or off-center-fed dipoles (like the Windom) can be used, though they often necessitate an antenna tuner and a counterpoise or radial network. Dipole antennas do not need to be perfectly horizontal; their legs can be bent or inclined, which affects feed point impedance and may require SWR experimentation with coaxial feed. Vertical antennas shorter than a half wavelength require an efficient ground system, typically comprising elevated or buried radial wires, with more radials generally leading to better efficiency. A 1:1 SWR indicates an impedance match but does not guarantee antenna efficiency; an inefficient vertical antenna with a poor ground system can show a low SWR while wasting most RF as heat. Investing in high-quality, low-loss feed line, especially coaxial cable, is crucial for maximizing RF signal transfer and overall antenna system performance.

Antenna modeling discussions about What happens if... a dipole is bent horizontally, laterally, vertically. Zig-zag, meander, catenary curve. Effect of sag, elevation, radials. OCF off-center feed, harmonics. Includes 4NEC2 antenna models for each study.

A vertical antenna project for the 7MHz made with some spare parts. Based on a broken 20 foot fishing pole, it is based on a good ground system made with radials and a capacitive hat done to increase the global radiation resistance of the antenna. A custom loading coil is also included in this project to perfectly tune the antenna to the CW portion of the 40 meters band.

The Superantennas MP-1 portable HF antenna is analyzed for its design and field performance, particularly its high-Q loading coil and 3/8-inch mounting. The review details the antenna's construction, including an 8-inch vertical section, a large-diameter loading coil tuned by a sleeve, and a 4-foot whip that disassembles into six rods for transport. Initial testing with the supplied 10-foot ribbon cable "ground plane" yielded poor SWR and RF hot conditions, indicating an inadequate ground system. Further experimentation with longer radials and resonant counterpoises for each band improved matching and eliminated RF hot issues, but introduced significant operational complexity. The author notes the difficulty in optimizing both counterpoise length and coil setting without an antenna analyzer, and the sensitivity of the MP-1 to counterpoise deployment. The review also discusses the recommendation to tune for maximum received signals rather than minimum SWR, often necessitating an external ATU due to the antenna's typical low impedance. The **MP-1**'s critical dependence on resonant counterpoises for effective operation, especially when elevated, is highlighted as a major drawback for portable use. The author ultimately sold the antenna, concluding that despite its sound technical design, its fussy nature and the need for extensive counterpoise management or an ATU detract from its portability and convenience compared to simpler, less expensive dipole solutions. The **Superantennas MP-1** is deemed a flawed portable antenna, requiring considerable effort to achieve its claimed performance.

A simple drawing schematic of a portable field dipole for 14 MHz with dimensions in meters and instruction for setting up the antenna and to store the radial for easy transportation

A helically wound vertical antenna experiment. 14 meter of wire wounded on a 8 meter fishing pole with 4 elevated radials

Documents the construction of a **VHF/UHF** antenna addition for the Buddipole HF antenna system, leveraging the existing Versa-Tee component. The project details the fabrication of a custom antenna mount from angle aluminum, including specific drilling and tapping for 3/16"-24 bolts, and the creation of radials from Simpson Strong Tie Insulation Supports. It specifies radial lengths for 70 centimeters (6 inches from the center stud) and 2 meters (19 1/4 inches), noting the use of wire nuts for safety. The resource outlines the construction of a mast from 1/2" ID PVC conduit, connected with 3/8"-24 connecting nuts and bolts, mirroring the Buddipole's modular design. It describes the integration of a mobile dual-band antenna with a 3/8"-24 mounting stud and the custom coax setup with BNC and **PL-259** connectors. Field testing with an FT-817ND and a separate dual-band SWR meter confirmed good SWR on both 2 meters and the 440-450 MHz section of 70 centimeters, with positive reception reports during Field Day activities. Further, the article describes the creation of a custom carrying solution, including a 22-inch tripod bag and a fabric roll-up, to emulate the portability of the original Buddipole system.

A review of the GAP Challenger DX Antenna that is not a traditional 1/4 wave vertical, but is a vertical dipole, this gives it several advantages over a standard 1/4 wave vertical, mainly the reduced number of radials, with excellent performances.

This article describes a simple yet effective multi-band vertical HF antenna design that performs exceptionally well across 80m to 10m bands. The antenna consists of a 13.4m wire mounted on a 12.4m Spiderpole, complemented by four 12m radials and a ground rod. Initially tuned with a manual LC circuit, it was later upgraded with a CG3000 remote auto ATU for convenient band switching. Despite antenna modeling software suggesting limited performance on higher frequencies, the system demonstrated excellent DX capabilities across all bands, outperforming more complex vertical antenna designs.

This document details the construction of a multi-band end-fed antenna, suitable for situations with limited space for larger antennas. The design utilizes a 1:49 to 1:60 impedance transformer to match a half-wave wire antenna fed at one end. Compared to a traditional dipole, this antenna resembles a highly unbalanced Windom antenna with one very long leg and a virtual short leg. The design eliminates the need for radials but relies on the coax cable shield for grounding. The document recommends using at least 10 meters of coax and installing a common mode filter at the entry point to the shack for improved performance.

This article presents the C-Pole antenna project, a compact, ground-independent vertical antenna designed for amateur radio operators. It features a folded half-wave dipole configuration that eliminates the need for radials, making it suitable for various locations, especially in deed-restricted areas. The C-Pole offers efficient performance with a 2:1 SWR bandwidth of approximately 3%, and it can be easily constructed using common materials. Additionally, the article discusses practical aspects such as feed-point impedance transformation and balun design to optimize functionality and minimize losses.

The article details the C-Pole antenna project, emphasizing its portability and ease of setup for amateur radio operators. Key features include its compact design as a vertical half-wave dipole that requires no radials, making it functional at various locations. The antenna employs capacitive loading to reduce physical length while maintaining efficiency. It includes practical advice on resonance tuning, impedance matching, and construction materials, along with a calculator for determining dimensions based on desired frequencies. Overall, it presents a user-friendly solution for portable ham radio communication.

Inverted L antenna, even if not completely freestanding, it only requires one line to be lauched into a tree to support the end of the horizontal wire. This project is done with a 31-foot Jackite pole for a support and uses six 15-foot radials and one 33-foot radial.

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.