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Showing posts with the label SWR

Simple Ham Radio Antennas: Lesson 4.3 Feed Lines and SWR. Post 342

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This is part of a continuing series of antenna videos produced by Dave Casler (KE0OG). This discussion on Feed Lines and SWR is aimed at newly licensed hams or those thinking about taking the Technician Class License Exam. Dave's presentation is smooth, simple, and completely understandable. This video would be an excellent way to supplement the ARRL Ham Radio License Manual (Technician Class). For the latest Amateur Radio news and events, please visit 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 . Thanks for joining us today! Aloha es 73 de Russ (KH6JRM). Related articles ARRL Introduces Kindle Edition of Ham Radio License Manual Ham Radio Morse Code Channel! New ham radio promotional video

Simple Ham Radio Antennas: A portable HF vertical antenna for 20 meters. Post #314.

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.If you need an emergency or portable antenna for 20 meters, then this video by Dave (W0ZF) will get you on the air quickly and inexpensively. The only materials I had to buy were some nylon rope and a telescoping fiberglass fishing pole from the Hilo " Sports Authority " outlet. The pole cost me $30.00. I followed Dave's instructions and soon had a light weight portable antenna that performed well in a local beach park I used for testing. The vertical element should be a quarter wavelength for the 20 meter frequency of your choice. I chose 14.200 MHz and cut my vertical element and my radial wires to a length of 16.47 feet (16 feet, 5.6 inches)/5.02 meters. My coaxial feedline was 50 feet/15.24 meters of RG-8X coaxial cable with UHF connectors. I used a spare Budwig Hi-Que center coax connector to attach the antenna elements, with the + side connected to the vertical element and the - side connected to the ground radial system. My antenna wire and radials wer

Simple Ham Radio Antennas. A basic 40/15 meter dipole. Post #276

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My antenna "farm" at the new QTH finally is taking shape. So far, I've built and used successfully a 40-10 meter inverted V fed with ladder line , a 5/8 wavelength vertical for 20, 15, and 10 meters, a 135-ft/41.15 meters "classic doublet" fed with ladder line that works from 80-10 meters, and a 40-10 meter delta loop fed with ladder line.  I've described these antennas in past posts.  All of them work very well with relatively low power (less than 50 watts) with my older rigs (Argosy II, Swan 100 MX, Yaesu FT-7, and a Kenwood TS-520). Although I prefer multiband HF antennas fed with 450-ohm ladder line, I still use a few single or two-band antennas fed with 50-ohm coaxial cable when I wish to experiment on 40 or 15 meters.  Last Sunday, 18 May 2014, I decided to build a simple two-band dipole covering the 40 and 15 meter bands using a single piece of RG -8X coaxial cable. The dipole would be designed for the lowest frequency range and then use the thir

Simple Ham Radio Antennas: The Ghost of Antennas Past--the simple vertical. Post #269

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Over the past few posts, I've been describing some of the antennas I designed, built, and used during my days as a novice amateur radio operator (1977-1978).  Most of the working designs were copied into school theme books and saved for future reference. One of my favorite homebrewed antennas was a simple vertical  antenna supported by a high tree limb terminating with a slightly angled ground plane consisting of 10 radials.  The antenna was designed for 40 meters and worked very well for contacts throughout the Pacific Rim and the mainland United States . Last weekend, I decided to duplicate that antenna with some spare wire, ceramic insulators, coaxial cable , and basic tools. As mentioned earlier, the process of moving to a new home often uncovers items you once thought were lost.  Such was the case here when I found several 50-ft /15.24 meters rolls of #14 AWG house wire in the garage.  That wire would serve as the vertical element and the rudimentary ground radial sys

Simple Ham Radio Antennas: Antennas without "tuners", part 3. Post #256

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In some of my previous posts, I've investigated, built, and used multiband dipole and inverted vees using a single 50 ohm coaxial feed line .  With a telescoping fiberglass mast (33-ft/10.06 meters extended), a simple halyard and pulley system, and separate antennas cut for each band of use (40, 20, 15, and 10 meters), I've been able to change bands fairly quickly by lowering the dipole/inverted vee elements, substituting those of another band, and raising the new antenna.  With each band element cut for the desired frequency, the efficiency is high with low swr for that band.  Since each antenna element is trimmed for the lowest swr at my mast location, an antenna transmatch isn't necessary.  Sometimes, as in the case with the 40 meter dipole/inverted vee, an antenna cut for the cw portion of the 7 MHz band will often work well on the phone portion of 15 meters (21 MHz band). The 15 meter band will operate on the third harmonic of the 40 meter band . In order to save