Amateur Radio Antenna Loading Coil, Multiband Vertical

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HF Loading Coil FormerThis is a simple yet capable coil former. You can use it to create a fixed inductance coil or add taps and use a crocodile clip to adjust the inductance as needed. I personally use it to switch between the 20m and 40m bands.I can also recommend the use of butterfly nuts or printed adapters on regular M4 nuts, which will allow you to connect and disconnect it by hand.If you plan to attach my mounts, you'll need to have two M4 screws on hand. They are designed to fit onto a 30 mm pole using zip ties.I have designed it for a 1 mm enameled copper wire. The created coil has a diameter of 50 mm and a maximum of 33 turns. The pitch between windings is 3 mm.If you want to create a loading coil for a multi-band vertical antenna, you can calculate the needed inductance using an online calculator for a loaded vertical, and then input the necessary data into the Coil 64 program, which is what I recommend. Please refer to the last image for a reference. The only thing you will need to change is the number of turns; try to adjust them to get as close as you can to the previously calculated inductance. If you are using a different diameter of wire, make that change as well.For long-term outdoor use or for higher power applications, it's advisable to consider using materials like ABS or other high-temperature-resistant materials. I've personally used it with 20 W of power during the summer with no issues (mine is just PLA).Check out my profile where I have a bike mount for a vertical antenna.Thanks for reading, enjoy the radio73 de SP6GK