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Learn how to avoid the half wave lengths and multiples that cause high swr and tuning problems with random wire antennas. See a table of frequencies and lengths to use or avoid for optimal performance on HF bands.
The graph below shows lengths to avoid for different collections of bands. The fewer bands, the fewer high impedance regions to avoid. You also want the antenna to be at least 1/4 wavelength long for each band you plan to use. For instance, to work 40m be sure the antenna is at least 10m or 33' long.
Learn how to avoid the half wave lengths and multiples that cause high swr and tuning problems with random wire antennas. See the table of good lengths for each band and the revised list of bad lengths to avoid.
All you need for a random wire antenna is some wire, your tuner, one or more supports up as high as you can get them to string the wire from the supports to the tuner, at least one or two insulators and a little time.
The term “random” infers that you can use any length of wire you want as an antenna, while that basic fact is true, there are some practical considerations. And I’m going to keep this VERY simple because there are scores of books dedicated to antenna design and eficiency.
Random Wire Antenna Lengths. A so-called random wire antenna is an end fed antenna. As typically installed, it is a compromise antenna but great for portable use because it is easy to pack and easy to install.
26 kwi 2012 · Learn how to calculate the optimal length of a random wire antenna for amateur radio bands using a program and a chart. Find out the gaps in the quarter-wavelength frequency spectrum and the preferred electrical lengths of the antenna.
