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Simple Ham Radio Antennas: A 5/8 wavelength 2 meter mobile antenna. Post # 353

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I ran across this excellent "homebrewed" antenna video by Australian amateur radio operator Margaret (VK4MH) while I was searching for a replacement for my old Larsen 2 meter mobile antenna which has seen better days. The project appears to be a simple, basic design that can be made from readily available parts available at a home improvement or hardware store. If you want to take a shortcut, you could use an old Firestick CB antenna as the fiberglass form for the antenna. Just unwrap the old wire, leaving the fiberglass rod intact. You can use the base to attach to a CB mount and the adjustable tip at the top for tuning the antenna. Wind your coil and helix along the rod as specified in the video. Adjust the "stinger" at the top for tuning, and you're ready to go. Nice project from a few years ago (2008). 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 commun

Simple Ham Radio Antennas: Non-Resonant Random Wire Antenna. Post #352

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A nice, simple, uncomplicated, and easy to understand tutorial on how to make a "Non-Resonant Random Wire" Antenna from Stan Gibiliso (W1GV). I've built a few of these non-resonant antennas of varying lengths, each using materials I found around the shack or at the nearest home improvement outlet. For the purpose of Stan's lesson, he chose a length of wire measuring approximately 250 feet/76.21 meters. If you follow Stan's simple instructions, you'll find this distant relative of the beverage antenna works very well on 160, 80/75, 40, and even 30 meters. Stan stresses the importance of having both a good electrical ground and a RF ground. Stan shows you how to avoid current loops and nodes, things that create RF problems in the shack. You will need an antenna transmatch ("tuner") to make this antenna work properly. I have a similar antenna at my vacation home in the Puna District of Hawaii Island and it works very well on 80, 75, and 40 met

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

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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 a

Graphene-Based Nano-Antennas May Enable Networks of Tiny Machines - Department of Electrical Engineering. Post #350

Graphene-Based Nano-Antennas May Enable Networks of Tiny Machines - Department of Electrical Engineering : "Graphene-Based Nano-Antennas May Enable Networks of Tiny Machines Networks of nanometer-scale machines offer exciting potential applications in medicine, industry, environmental protection and defense, but until now there’s been one very small problem: the limited capability of nanoscale antennas fabricated from traditional metallic components. Assistant Professor Josep Jornet's research with his advisor, Professor Ian Akyildiz on graphene based nano antennas has been featured by the Science andTechnology News Center of Georgia Tech. The project shows that "the concept of graphene-based nano-antennas is feasible, especially when taking into account very accurate models of electron transport in graphene. Many challenges remain open, but this is a first step toward creating advanced nanomachines with many applications in the biomedical, environmental, industri

Pyramid nanoscale antennas beam light up and down. Post #349

Pyramid nanoscale antennas beam light up and down : "Researchers from FOM Institute AMOLF and Philips Research have designed and fabricated a new type of nanoscale antenna. The new antennas look like pyramids, rather than the more commonly used straight pillars. The pyramid shape enhances the interference between the magnetic and electric fields of light. This makes the pyramid-shaped antenna capable of enhancing light emission and beaming different colours of light towards opposite directions. This finding could lead to more efficient light emitting devices (LEDs). The researchers published their results online on 12 December 2014 in Physical Review Letters. Individual antennas A straight nanoscale antenna will mainly respond to the electric field of light. This means that the effects of the magnetic field of light, which holds half of the energy of light, are disregarded. For a long time this was not considered as an issue that could be solved, because most of the metals use