If you want me to build this. Let me know. However, in this video I explain the principles behind antenna design using Maxwell’s equations and the moment method starting with a simple vertical antenna, I demonstrates how we can predict resonant frequencies and also how we can make the antenna shorter while still maintaining its resonant frequency.
Then, let’s look at adding a coil to a vertical antenna, and how this affects the resonant frequency of the antenna’s harmonic – for instance how 7MHz is also resonant on 21MHz. Using a combination of the moment method (software simulation) and spreadsheet calculations, I’ll demonstrate how the position and value of the coil can change the antenna’s harmonic frequencies.
This video is a great resource for ham radio enthusiasts who are interested in understanding the technical aspects of antenna design and how to optimize their antennas for specific frequencies. Whether you’re a beginner or an experienced radio operator, you’ll find valuable insights and practical tips in this informative and engaging video.
In a nutshell, this isn’t an end-fed but a Dipole or a Vertical. I am VERY excited about this research. Can it be right? Using a loading coil to pull the 3rd harmonic for 21MHz down to 14.2MHz. Let me know what you think – then we can head out to the field and see if this works.