ZS6BKW Multi-band Antenna
Construction and Tuning of the ZS6BKW Multi-band Antenna: An Optimized G5RV Variant
Description
The ZS6BKW multi-band antenna, an optimized variant of the classic G5RV, is presented with detailed construction and tuning instructions. This resource outlines the antenna's design principles, which were developed by Brian Austin (G0GSF) using computer programs and Smith charts to achieve optimal dimensions. It provides specific guidance on calculating and adjusting the lengths of the radiators (L1) and the matching ladder line (L2), emphasizing the critical role of velocity factor (VF) in achieving resonance.
The article includes a step-by-step procedure for empirically determining the VF of ladder line using an antenna analyzer, ensuring accurate physical lengths for the matching section. It details the tuning process for the radiators, offering practical tips for incremental adjustments to achieve the best SWR curve. The resource presents SWR measurement results obtained with an AIM-4170C analyzer across multiple bands, alongside predicted SWR graphs from an AutoEZ model. It confirms successful contacts on 80, 40, 20, and 17 meters, including a 17-meter DX contact to Italy.
EZNEC and AutoEZ models for the ZS6BKW antenna, covering 80 through 6 meters, are provided for download, allowing further analysis and customization. The document specifies component details, such as the use of Wireman 554 ladder line and #14 AWG THHN copper wire, and discusses the antenna's performance characteristics, noting high SWR on 15 and 30 meters but successful tuning on 6 and 80 meters with an external tuner.