3 Bands Vertical Antenna for WARC bands

This article describes the construction of a three-band vertical antenna for the WARC bands (10, 18, and 24.9 MHz). Unlike a previous design using thin wire requiring a complex matching device, this version uses a telescopic set of pipes, reducing reactances and simplifying the matching device to two coils and two capacitors.
The article provides details on the antenna model, the matching device circuit, and tuning methods, including the use of frameless coils and variable capacitors.
With proper tuning, the antenna achieves a VSWR not exceeding 1.3 across all bands, demonstrating a practical and efficient design for amateur radio enthusiasts.