The W5GI Multiband Collinear Antenna is a classic and highly practical HF antenna design that continues to attract amateur radio operators who want wide frequency coverage with simple construction. Covering 80 meters through 6 meters, this antenna offers reliable performance on multiple bands when used with an antenna tuner, making it an excellent choice for limited-space installations and home stations alike.
Originally popularized by W5GI, this antenna stands out because it combines coaxial collinear sections with insulated wire elements, creating a structure that behaves differently from conventional dipoles or G5RV-style antennas. Many operators report noticeably better results compared to a standard G5RV, especially on 20 meters, where SWR is typically around 1.6:1.
Understanding the W5GI Multiband Collinear Antenna Layout
At first glance, the W5GI Multiband Collinear antenna may look complex, but its working principle is surprisingly straightforward. The total length of the antenna is approximately 100 feet, divided symmetrically around a central insulator and feedpoint. Each side of the antenna consists of insulated wire sections and coaxial cable sections that act as impedance-transforming and phase-altering elements.
A key feature of this design is the 16.5-foot coaxial sections placed inline with the radiating wire. These coax segments are not used as feedline in the conventional sense; instead, they function as reactive elements, shaping current distribution along the antenna. This is one of the reasons the W5GI behaves more predictably across multiple bands than random wire antennas.
The antenna is fed using 300-ohm TV twin lead, approximately 34.7 inches long, connected to a current balun or choke before transitioning to 50-ohm coaxial cable such as RG-8X. This balanced-to-unbalanced transition helps reduce common-mode currents and improves overall radiation efficiency.
W5GI Multiband Collinear Antenna – Construction Details
One important detail shown in the diagram is how the coaxial sections are connected. The shield of the coax is soldered to the center conductor, effectively turning each coax segment into a specific electrical length rather than a traditional transmission line. Using 12-gauge wire for the connections ensures good mechanical strength and low loss.
Insulators at the ends and center provide strain relief and electrical isolation, allowing the antenna to be installed as a flat-top, inverted-V, or slightly sloped configuration depending on available space. While height is always beneficial, many operators have achieved good results with this antenna installed at moderate heights.
On-Air Performance and Band Coverage
In real-world operation, the W5GI antenna is known for its balanced performance across HF bands. With a suitable antenna tuner, it can be used effectively from 80 meters through 6 meters, making it ideal for operators who want one antenna for SSB, CW, and digital modes.
Compared to a G5RV, users often report stronger signal reports, quieter reception, and more stable tuning behavior, particularly on 20 meters and above. While it is not a resonant antenna on every band, its impedance characteristics are generally tuner-friendly.
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