A practical guide to beam arrays from 20m to 70cm
RSGB, Bedford 2021, M Parkin, G0JMI, 208 Seiten, engl.,, ISBN: 9-781-9101-9505-8
Yagi Antennas have become commonplace in amateur radio since their invention in the 1920s by Shintaro Uda and Hidetsugu Yagi. These directional antennas, consisting of two or more parallel resonant antenna elements, provide, as Radio Amateurs know, great performance across a variety of bands. If you have ever wanted to build and experiment with Yagi beam arrays then Yagi Antennas Explained is for you.
Yagi Antennas Explained is a practical guide to the design, operation and construction of Yagi beam arrays for the amateur bands from 20m to 70cm. Rather than using mathematics, where possible, explanations have been used to describe the operational aspects of beam arrays. So, you will find explanation of gain, front to back ratio, feed point impedance, polarisation, radiation pattern and bandwidth. Antennas need to be connected to the radio equipment using feeder cables. Therefore, the feeder cables are reviewed along with the techniques utilised to match a feeder cable to an antenna. Practical techniques for construction are offered in abundance by Yagi Antennas Explained with the emphasis being placed on using hand tools and materials that are generally available.
There are many practical designs included, ranging from a 15m band 2-element beam, through to a 70cm band 19-element Yagi. Installations are also covered, including how performance can change as height above the ground increases and the effect of mounting several Yagi beam arrays on the same mast. The final chapter describes techniques where Yagi beam arrays can be combined to produce specialised antennas. This includes how Yagi beam arrays can be stacked or bayed. A method is described where two Yagi beam arrays can be combined to produce a dual-band antenna fed using a single feeder cable. Other examples include how two Yagi beam arrays can be combined to produce a circularly polarised beam antenna suited to use when the distant station’s polarisation is uncertain.
If you want a practical and understandable guide to the fascinating world of building, operating and experimenting with beam arrays from 20m to 70cm then Yagi Antennas Explained is certainly the book for you.