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Showing posts with the label Feed Line

Simple Ham Radio Antennas. A 20 meter through 10 meter Vertical Dipole Antenna. Post #284.

One of the joys of moving into a bigger home with a decent back yard (1 acre of mixed brush and trees) is the ability to build the wire antennas I've always wanted.  Like many of my fellow amateur radio operators, I've endured HOAs, CC &Rs , and limited space for most of my 37 years as a ham.  I operated fairly well under these circumstances using stealth antennas from "ground hugging" loops to thin random wires stretching to the nearest tree. Now that my xyl and I are semi-retired, we have to the time to "fix up" our final home in an area conducive to our various hobbies, including gardening, amateur radio, backyard astronomy, and just plain relaxing.   Over the past few months, I've begun the erection of my "antenna farm" and the building of my radio room in the garage.  There's a lot of work to be done, but it's enjoyable and gives me exercise. Last Friday, just before the 2014 ARRL Field Day, I completed a new antenna whi

Simple Ham Radio Antennas: The Aluminum Foil Vertical. Post #278.

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I knew it would happen.  The time I ran out of antenna wire.  After several years of using old #14 AWG house wire, #18 AWG speaker wire from Radio Shack , and remnants from studio wiring projects at my former employer (Pacific Radio Group), I had finally exhausted my wire supply for homebrewed antennas.  What to do until the next sale at Lowe's, Home Depot , and Ace Hardware?  Give up? Banish the thought!. With last week's beautiful weekend before me, I needed some cheap wire to erect my latest antenna "masterpiece."  I found my resource in the kitchen in the form of a new roll of "Diamond Aluminum Foil"--the stuff my xyl uses for cooking tasty treats and dinners.  Since there were several new rolls near the stove, I decided to "borrow" a new roll and apologize later.  Besides, I would buy another roll the next time I visited the supermarket. According to the label on the container, the roll contained 66.66 yards (199.98 feet) or 60.96 meters

Simple Ham Radio Antennas. A 5/8 wavelength vertical antenna for 20 meters. Post #274

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How would you like to have a simple, effective antenna for 20 meters thast will give you some gain over a ground plane antenna and exhibit a radiation angle of approximately 15 degrees? You can grab more DX (distance) at a modest cost by building a 5/8 wavelength vertical antenna working in conjunction with 1/4 wavelength radials beneath the main radiating element. I've built 5/8 wavelength antennas for 10 and 15 meters and they work very well.  If you desire multiband performance out of this antenna, you will need a balanced feed line (such as 450-ohm ladder line), a 4:1 current balun, and a sturdy ATU ( antenna tuning unit ).  If you prefer to use this antenna on one band only, you can establish resonance with a base loading coil that tunes the antenna to 3/4 wavelength  resonance.  Standard 1/4 wavelength wire radials are used with both versions of this antenna. According to William I. Orr (W6SAI) and Stuart D. Cowan (W2LX), "a 5/8 wavelength antenna provides imp

Simple Ham Radio Antennas: A 5/8 wavelength vertical ground plane. Post #272

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According to Edward M. Noll (W3FQJ), "The 5/8-wavelength vertical is a preferred length for the best low angle radiation."  For the higher HF bands (20 through 10 meters), this antenna is easily assembled and requires a small quantity of wire, some ceramic insulators, a suitable mast, 50-ohm feed line or 450-ohm feed line, a simple ground radial system, and a sturdy antenna matchbox or ATU .  Multiband use between 20 and 10 meters is possible with 450-ohm ladder line , ATU, and a balun, while good single band use can be obtained with 50-ohm coaxial cable and an inline or base antenna "tuner". So, let's build a simple 5/8 wavelength vertical for the 10 meter amateur radio band, centering on 28.4 MHz .  This frequency is at the mid-point of the SSB allocation for Technician Class licensees.  The antenna was built at my new home in the Puna District on 18 April 2014. MATERIALS: Using the general formula, 585/f (MHz)=L (ft), our vertical element will measur

Simple Ham Antennas: The Novice 40 meter delta loop. Post #271

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During that brief period between getting my novice amateur radio license and moving on to the technician and general class license (1977-1983), I built several dipoles, inverted vees, and verticals.  All of these antennas worked very well, considering the lack of space I had at the time.  When my xyl and I moved from Honokaa to Laupahoehoe , we occupied a larger home and had more backyard space to place antennas. Just before I passed the Advanced Amateur License exam, I built what I considered my best and "most forgiving" antenna--a full-wavelength 40-meter loop.  The loop displayed some gain over a dipole at the same height, needed only one tall support, and didn't require a ground radial system to operate efficiently.  Using balanced feed line , a 4:1 current balun, and a Drake MN-4 transmatch, I could cover 40, 20, 15, and 10 meters with one antenna.  Later on, when 30 meters became available to amateur radio operators, I used a MFJ-941-E Versa Tuner II and my sp