![]() ![]() Adjust the air variable capacitor to get the SWR to be as low as possible at your desired operating frequency. Connect the antenna analyzer to the red wire BNC connector. This will simulate the impedance of a vertical antenna. Connect the 5000-ohm resistor across the binding posts. If you have an antenna analyzer, you can test the antenna at your workbench to check that everything is properly connected before going out into the field. 14.2 is a frequency approximately in the middle of the band, which gives a length of 468/14.2 = 33 feet.Ħ. For example: The 20-meter band covers 14.0 to 14.35 MHz. Choose a frequency that’s in the middle of the band you wish to operate on. To determine the wire length, use the formula 468/frequency. Cut your half-wavelength antenna wire(s). Once again, these are not polarized, so it doesn’t matter which binding post is connected to which terminal.ĥ. ![]() Connect the air variable capacitor to the binding posts. Solder two short pieces of wire to the terminals of the air variable capacitor.Ĥ. Connect wires 2 and 3 to the BNC connectors.ģ. Connect a binding post to each end of wire 1 (these are not polarized, so it doesn’t matter which connector is connected to each wire). Also on top of the first wire, wrap a third wire around the toroid four times (I used a black wire for this).Ģ. On top of the first wire, wrap a second one around the toroid three times (I used a red wire for this). Make sure the first wire is wrapped evenly around the whole toroid. ![]() Wrap the first wire around the toroid 27 times (I used a black wire for this). Start by wrapping the wire around the toroid. from )Īntenna analyzer (recommended, but not necessary. 4 jumper wires with alligator clips (you may need more) 5000-ohm resistor (recommended for testing) Solid Core Wire (two colors, 24-gauge recommended)Ĭ. Here are instructions for making a multiband end-fed half-wavelength antenna that works on 17, 20, 30, and 40-meter bands.Ī/B. This makes it very convenient to throw the antenna up in a tree and connect the bottom of it to your radio. A dipole has its feedpoint (where it connects to the radio) in the middle of the antenna, but an EFHWA’s feedpoint is at one end. This type of antenna is similar to the common half-wavelength dipole, but with one significant advantage. Showcasing amazing maker projects of 2022įor portable radio operation, I like End-Fed Half-Wavelength Antennas (EFHWA, pronounced “EF-WAH”). Gift the gift of Make: Magazine this holiday season! Subscribe to the premier DIY magazine todayĬommunity access, print, and digital Magazine, and more Share a cool tool or product with the community.įind a special something for the makers in your life. Skill builder, project tutorials, and more Get hands-on with kits, books, and more from the Maker Shed Initiatives for the next generation of makers. Membership connects and supports the people and projects that shape our future and supports the learning.A free program that lights children’s creative fires and allows them to explore projects in areas such as arts &Ĭrafts, science & engineering, design, and technology.Microcontrollers including Arduino and Raspberry Pi, Drones and 3D Printing, and more. Maker-written books designed to inform and delight! Topics such as.A smart collection of books, magazines, electronics kits, robots, microcontrollers, tools, supplies, and moreĬurated by us, the people behind Make: and the Maker Faire.Together tech enthusiasts, crafters, educators across the globe. A celebration of the Maker Movement, a family-friendly showcase of invention and creativity that gathers.The premier publication of maker projects, skill-building tutorials, in-depth reviews, and inspirational stories,. ![]()
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