The placement of a coil on an element affects the third harmonic. If you can work out exactly where to put this coil, we can then force a harmonic on almost any band you like. In this example we have made a compact 40m antenna of only 6.5m long and then made 20m to work on the third harmonic with very little loss. See what you think. Callum.
https://youtu.be/uNqA6dy6cbY – Last Video Discussing this Concept
https://youtu.be/L9HX7352ukw – End Effect Discussion
https://youtu.be/V8Qq4-0_TjQ – The Custom Hybrid SkyLab
https://youtube.com/live/x-za2pjmNjE – Live Stream where I Switched Between