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This antenna is an off-center fed spiral dipole for 40 meters. The spiral dipole is very compact, making it well-suited for limited space (like an apartment patio), while the off-center feed gives the antenna some multiband capability.

The OCFD Off-Center-Fed Dipole Antenna is an excellent multiband antenna that is relatively simple to construct, yet gets quite decent performance.

A portable home made wire dipole antenna that works on 40 30 and 17 meters band.

One of the featured products, the V350 CAMP, is a multiband vertical antenna covering 6 to 80 meters, priced at R$ 799,90, demonstrating the range of ready-to-use solutions available. The inventory includes various antenna types such as **HF**, **VHF**, and **UHF** designs, along with dual-band options like the J-Pole Dual V/UHF for R$ 235,00. For those building their own arrays, the store stocks essential components like element holders, clamps, junction boxes, and aluminum plates, alongside specialized items such as the KIT Isolador Central Dipolo - 01DX for R$ 99,90. The shop also provides a comprehensive selection of installation hardware, including diverse antenna mounts, PTT supports, and various coaxial cables like RG58 and RG213, with prices up to R$ 849,90 for RG213. Connectors such as UHF male PL259 and various adapters are readily available, ensuring compatibility for different setups. Additionally, specialized items like side handles for popular transceivers such as the FT857/891 and IC7300 are offered, catering to specific equipment needs. Beyond antennas, the store supplies practical accessories like transport bags, 12V power cables for transceivers, and even branded merchandise like the Antena Kit mug. Rodrigo Gonçalves, PP5BT, manages the operation from Blumenau, SC, Brazil, providing direct contact via WhatsApp at +55 47 9.9985.0155.

A Multiband Slinky Coil for the PAC-12 portable Antenna, can be used also as a dual PAC-12 dipole by James Bennett

This antenna is a classical antenna working on 7,10,14,18,50 MHz is implemented with three traps for 30, 17 and 6 meters

The Linked Dipole is a multiband antenna designed for 80/60/40/30/20m bands, optimized for the (tr)uSDX low bands configuration. It incorporates a 1:1 Balun to prevent common mode currents, ensuring balanced operation with coaxial cable. The Balun, wound on an FT140-43 core, achieves 37-40dB attenuation. The design includes a 3D-printable housing for compactness and waterproofing, with labeled link insulators for ease of use. Wire lengths were meticulously adjusted for optimal performance with a 7m pole and 3m rope extension, ensuring the antenna's ends are off the ground for improved behavior. The project includes downloadable printables for DIY construction.

A 60-foot available space, for example, might necessitate a shortened multiband dipole array to cover 80, 40, and 15 meters effectively. This resource details the construction of such an antenna, combining full-size and coil-loaded dipoles on a single feedline. It addresses the common challenge of fitting multiple HF bands into restricted physical footprints, providing practical guidance for hams with smaller backyards or portable operations. The core of the offering is an interactive calculator that determines required loading coil inductance and dipole lengths for various amateur bands from 160m to 10m. Users input their available space, and the tool provides dimensions, coil turns, and an efficiency rating (Good or Fair) based on the antenna's electrical length relative to a quarter-wavelength. It also suggests suitable _PVC_ pipe diameters for coil forms. The article further illustrates a center feed-point assembly using an 18-inch section of 2-inch _PVC_ pipe, detailing eye-bolt spacing and coaxial connector installation. It emphasizes the importance of adequate spacing between parallel dipoles and offers customization options for the feed-point, including the addition of a _Balun_ for improved feedline isolation.

The CobWebb antenna project is a compact, multiband HF solution ideal for amateur radio operators. Covering 14-28 MHz, it features a square dipole array with near-omnidirectional coverage and unity gain. This guide details a DIY approach, using a 1:4 current balun for impedance matching. Construction involves aluminum and fiberglass tubing, with optimized element tuning for SWR performance. Weather resistance improvements and resonance shift considerations are also discussed. Build your own CobWebb antenna for an efficient, space-saving HF experience.

This PDF guide provides detailed instructions and diagrams for constructing a fan dipole antenna, a popular choice among hams for multiband operations. The guide covers the design, materials needed, and installation process, offering step-by-step guidance to help hams set up an effective antenna system for their radio operations.

A coaxial cable trap is a fundamental component in multiband antenna design, enabling a single radiator to resonate efficiently on multiple frequencies by electrically shortening or lengthening the antenna element. This project focuses on constructing such a trap for a vertical antenna operating on the 10 MHz (30m) and 14 MHz (20m) amateur bands, providing practical insights into its fabrication and integration. The article outlines the specific dimensions and winding techniques for the coaxial trap, emphasizing the use of readily available materials. It details the physical construction of the vertical element, including the mast and radiating sections, to achieve optimal performance across both target bands. The author shares personal experiences with similar trap designs, noting their effectiveness in previous horizontal dipole configurations. Key construction steps are illustrated with _original photos_, showing the assembly of the trap and its incorporation into the overall antenna structure. The design aims for a compact footprint, making it suitable for limited space installations while still delivering effective DX capabilities on the **30-meter** and **20-meter** bands.

Being frequently away from home, the author owner of an Elecraft KX3 missed the opportunity to work /M. They devised a portable antenna solution, incorporating a coil and car body, enabling multi-band tuning. Despite its unconventional design, the antenna exhibits promising performance, resembling a vertical dipole.

The multiband tuned doublet, or center-fed Zepp, is a simple and efficient HF antenna that operates effectively across most amateur bands using a balanced parallel-wire feedline and antenna tuner. Unlike coax-fed dipoles, it tolerates impedance mismatches with minimal loss. By selecting suitable feedline and dipole lengths, one can achieve stable multi-band operation. While it doesn’t match monoband Yagis, it offers excellent performance, low cost, and broad coverage. Its radiation pattern and efficiency vary with frequency, but it remains a practical and versatile solution for HF operators.

For amateur radio operators engaging in portable operations like SOTA or POTA, rapid deployment of an effective antenna system is paramount. This video resource details the assembly process for the Buddipole multiband dipole antenna, showcasing its components and how they fit together. Rob, VK5SW, systematically presents the mast, coil arms, radiating elements, and the VersaTee hub, emphasizing the modular design that allows for quick configuration changes across various HF bands. The demonstration highlights the antenna's adaptability for different operating environments, from a ground-mounted vertical to a horizontal dipole. The video illustrates the ease with which the antenna can be packed and deployed, making it a practical choice for activations where setup time is limited. The Buddipole's design facilitates efficient band changes and tuning, crucial for maximizing QSO opportunities during field operations.

This document provides comprehensive guidance on modeling and constructing multiband dipole antennas using traps. It addresses common segmentation issues in EZNEC modeling software, recommends optimal segment lengths for trap models, and compares trapped dipoles with paralleled multiband dipoles. While trap dipoles are significantly shorter, they exhibit lower gain and narrower bandwidth. Detailed instructions for building weatherproof coaxial traps include material lists, construction steps, and tuning methods. The guide notes that properly constructed coaxial traps introduce only minimal signal loss (0.6 dB) while offering practical multiband performance in a compact design.

A 13-foot total radiating element length is achieved by combining a Buddipole Long Telescopic Whip with 4 feet of modified tripod tubes, forming a low-profile, multiband antenna for **POTA** operations. The resource details the transformation of an Amazon Basics Aluminum Light Photography Tripod Stand, focusing on electrically isolating the top two radiating sections from the bottom support. John, VA3KOT, outlines component sourcing, including the 9-foot 4-inch fully extended whip, and emphasizes using adhesive copper tape for reliable electrical contact and conductive grease to prevent oxidation at tube connections. The construction process, while not requiring specialized tools, highlights careful assembly to ensure proper electrical conductivity and mechanical stability. The author's experience with this setup suggests its effectiveness for portable activations, offering a discreet profile compared to larger antenna systems. The design prioritizes ease of deployment and transport, making it a practical solution for operators seeking a compact yet versatile antenna for field use.