Posts

An 80-Meter Vertical Helix

Like many amateur radio operators, I live on a small lot surrounded by neighbors, utility lines, and civic-minded citizens concerned about the "attractiveness" of my community.  Whether by design or outright fear, I've adopted the "stealth" approach to ham radio antennas.  It's the old "out of sight, out of mind" idea applied to amateur radio antennas. The amateur radio press is full of articles describing the struggle of amateur radio operators to pursue their hobby under the burdensome regulations of CC & Rs, HOAs, and other civic minded citizens who object to antenna farms.  So far, my modest verticals, loops, and inverted vees have blended well with the vegetation and trees bordering my small backyard.  Vertical antennas have always been a problem because of the limited space for a radial system.  There are times, however, where a shortened vertical for the lower HF bands (such as 80/75 meters) is necessary where horizontal space is lack

A modified 20 meter extended double zepp antenna. Post #210

How would you like to boost your 20 meter signal by 3 dB with only 84.5 feet/25.76 meters of wire, two supporting masts, some 450-ohm ladder line, ordinary 50-ohm coaxial cable, and a few miscellaneous parts? Today, I ran across a fascinating article by Paul E. Fuller (N8ITF), who designed a simple data sheet to help you build what is called "an extended double zepp antenna."  The double extended zepp is a dipole type of antenna consisting of two collinear 0.64 wavelength elements fed in phase, providing approximately 3 dB gain over a dipole on its intended frequency.  By following Fuller's advice, you can build an antenna that will give you some gain and more DX in the process. Although my backyard is a bit cramped, there are numerous tall Norfolk Pine trees in an adjacent lot which could serve as a temporary support system for the 20 meter extended double zepp antenna. With Fuller's article in mind, plus a few other ideas from several amateur radio operators,

A simple 80 meter inverted "L" antenna. Post #209

Because my back yard is rather small, I haven't been able to erect a decent 80 meter dipole antenna.  In the past, I've used an inverted vee with elements measuring 67 feet/20.42 meters on a side.  Although the antenna worked reasonably well, it barely fit in back of my house and was clearly visible to my neighbors.  Another approach was needed. I decided to build an inverted "L" antenna, since I had some room to go up (vertical) and some room to go horizontal (flat top segment).  If I used a lightweight wire (#20 or #22 gauge wire) and placed a mast among some trees bordering my lot, I could have a working 80 meter antenna with some degree of stealth. An inverted "L" is a form of bent vertical, with the vertical section running up a mast for 1/8 wavelength (or more, if possible) and a horizontal wire running for 1/8 wavelength from the top of the mast.  Like all verticals, I would need a ground radial system to maximize efficiency and cut losses. Alt

Antenna Topics: A simple 30 meter vertical antenna

Every now and then I feel the need to get away from the crowded amateur radio bands and just relax with an easy-paced conversation on 30 meters.  The band, which stretches from 10.1 MHz to 10.150 MHz, is quite narrow and is restricted to cw and data transmissions. The pace of communications is generally more relaxed on 30 meters than in any other amateur radio band.  And since I need more practice in cw, this band is perfect for sharpening my skills.  Along the way I also meet some interesting and helpful people. In order to use 30 meters, I have to change rigs.  My old Swan 100 MX, Yaesu FT-7, and Kenwood TS-520 don't cover this band, so I rely on another excellent transceiver--the Ten Tec Argosy II.  This rig can run up to 50 watts output, but I prefer the 5 watt setting for most of my cw work.  I can run the Argosy II off my solar charged deep cycle marine battery all day without depleting the battery. Although I could use my 40-10 meter inverted vee fed by 450-ohm ladder

Antenna Topics: Disconnecting equipment for safety. Post # 207

Like many regions of the northern hemisphere summer has come to Hawaii Island.  Although this tropic paradise is known for its gentle climate, there are occasions where severe thunderstorms and lightning plague Hawaiian hams just like our fellow amateur radio operators on the U.S. Mainland.  Every now and then, a small sea-spawned tornado (waterspout) comes ashore in Kailua-Kona and does some minor damage to beach areas.  Most of these unwanted guests arrive on the strong winds of a frontal passage which begins north of Kauai and runs down the island chain to Hawaii Island.  While most of these severe storms occur during the winter months, it's not unusual for a bad thunderstorm to strike in mid-summer and cause damage to utility poles, transformers, and other electrical equipment. Now that I'm mostly retired, I tend to stay at home and can keep watch on the weather. With adequate warning, I can safely disconnect  my antennas and get my rigs out of danger before any storm st