Field antennas are essential for amateur radio operators who want to engage in portable operations, such as during events like Field Day or while activating summits (SOTA) and parks (POTA). These antennas must be lightweight, easy to assemble, and possibly multi bands. Homebrewing antennas not only allows operators to customize their own setups but also fosters a deeper understanding of antenna theory and construction. Below are five excellent online homebrewed antenna projects that are perfect for portable ham radio use.
Off-Center Fed Dipole (OCFD)
The OCFD is a popular choice for portable operations due to its versatility and ease of construction. It can cover multiple bands (typically 80m to 10m) without the need for a tuner. This design uses a balun to feed the antenna off-center, allowing for a more efficient radiation pattern. Many resources online provide detailed instructions for building an OCFD, making it accessible for all skill levels.
Multiband Center-Loaded Off-Center-Fed Dipole (CL-OCFD) antenna that work on 80m 40m 30m 20m 15m 10m. The Center-Loaded Off-Center-Fed Dipole (CL-OCFD) antenna, developed by Serge Stroobandt, offers a versatile solution for amateur radio enthusiasts, covering multiple HF bands (80, 40, 30, 20, 15, and 10 meters) without the need for an antenna tuner. This innovative design utilizes a capacitor for resonance on the 80-meter band and a resistor to manage static charges. The CL-OCFD enhances bandwidth and simplifies operation, making it a significant advancement on OCF Dipole design. (by ON4AA)
2. Magnetic Loop Antenna
Magnetic loop antennas are compact and efficient, making them ideal for portable use. They are particularly effective for QRP operations and can be built with readily available materials. The loop can be tuned to various bands by adjusting the capacitor, and many builders share their designs and tuning techniques online, making it easier for newcomers to experiment with this type of antenna.
A page describing how to setup a magnetic loop antenna with the DIY Magnetic Loop Starter Kit produced by Chamaeleon Antenna. Includes a video and a detailed instructions to setup. (by OH8STN)
3. End-Fed Half-Wave Antenna (EFHW)
The EFHW antenna is another excellent project for portable operations. It is lightweight, easy to deploy, and can be made to cover multiple bands with the addition of a matching transformer. Many hams have documented their homebrew designs, providing step-by-step guides that include materials needed and assembly instructions.
Constructing an End-Fed Half-Wave (EFHW) antenna offers a practical solution for HF operators seeking a multiband wire antenna without the need for extensive radial systems. This design typically employs a high-impedance transformer at the feed point, matching the antenna's inherent high impedance to a 50-ohm coaxial feedline. The article specifically details a 2012 approach, focusing on a transformer with a 49:1 turns ratio, which is a common configuration for EFHW antennas. The resource outlines the construction of a wire element cut for a half-wavelength on the lowest desired band, with specific coil arrangements enabling operation on harmonically related bands such as 40m, 20m, and 10m. It discusses the physical dimensions and winding details for the matching transformer, often utilizing a ferrite toroid core to achieve the necessary impedance transformation. The content provides insights into the operational principles and practical considerations for deploying such an antenna, including methods for tuning and optimizing performance across multiple amateur radio bands. While acknowledging that the presented information from 2012 may be superseded by newer insights, it serves as a foundational reference for understanding EFHW antenna theory and construction. (by PA3HHO)
4. Vertical Ground Plane Antenna
A vertical ground plane antenna is straightforward to construct and offers good performance for portable operations. It typically consists of a vertical element with several radials for grounding. This design can be made using simple materials like wire and PVC pipe, and various online resources provide detailed plans for building and tuning this type of antenna.
Homemade 40 through 6 meter HF portable multiband antenna, an aluminium antenna construction article, with plan, drawings and photos (by AD5X)
5. BuddiPole Antenna
The BuddiPole antenna is a modular, portable antenna system that can be configured as a vertical or dipole. It is designed for quick assembly and disassembly, making it perfect for field use. Many amateur radio enthusiasts share their homebrew variations of the BuddiPole online, offering insights into different configurations and performance tips.
This document outlines the construction of a homebrew Buddipole antenna variant, designed for portable use and emergency services. The antenna utilizes telescoping whips and loading coils, enhancing its versatility across various HF bands. Key components include fiberglass rods, brass fittings, and Anderson Power Pole connectors, ensuring robust electrical connections. The design emphasizes non-inductive materials to minimize interference, while practical assembly techniques, such as epoxy and heat shrink tubing, are employed for durability. This variant aims to improve upon traditional Buddipole designs, offering greater strength and functionality. (by AE5JU)
These projects not only enhance the portable ham radio experience but also encourage creativity and learning within the amateur radio community. Whether you are a seasoned operator or a beginner, these homebrewed antenna designs can help you make the most of your portable operations.
So I drilled down on the first of these antenna designs: If any readers want something to Geek out on, check this:
https://hamwaves.com/cl-ocfd/en/index.html