Saturday, December 27, 2014

Simple Ham Radio Antennas: How Antenna Tuners Work - KK4WW & N4USA. Post #351


This is an excellent antenna tuner tutorial from Gaynell Larson (KK4WW) and Dave Larson (N4USA). Dave covers all the basics, including SWR, basic tuner design, and proper use of antenna tuners. This video is a useful addition to your Amateur Radio Library. While it's possible to make antennas that don't require some kind of system to match the antenna impedance to your rig's impedance, most amateur radio operators I know use antenna transmatches ("tuners") to provide the best possible match between rig and antenna. This is especially important if the antenna is used for several amateur radio bands. The use of an antenna tuner is required if you use balanced feed lines, such as 450 ohm ladder line, 300 ohm television twin lead, or homebrewed balanced feed lines. A balanced tuner will do the job of matching antenna to rig. You could also run your balanced feed line into a 4:1 balun and then onto your tuner with a small length of 50 ohm coaxial cable, such as RG-8X or RG-8. Antenna tuners can maximize the use of a single wire antenna. Also, be sure to have a proper ground system for your shack. I use a copper grounding stake attached to four, 80 meter radials (each approximately 65 feet/19.81 meters) spread out through the rain forest in my back yard. I also attach a "multi-band counterpoise bundle" to the ground lug of my Drake MN-4 "tuner." This arrangement works well for my 80 meter delta loop, the 80 meter inverted vee, and the 135-foot/41.15 meters doublet antenna. This video from Dave and Gaynell contains a lot of useful information. For the latest Amateur Radio news and events, please check out the blog sidebars. These news feeds are updated daily. You can follow our blog community with a free email subscription or by tapping into the blog RSS feed. If you want more Amateur Radio news, please visit my news site at http://kh6jrm.net. Aloha es 73 de Russ (KH6JRM).