Posts

Simple Ham Radio Antennas--Folded Dipole Calculator. Post #996.

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Folded Dipole Calculator (http://www.changpuak.ch/electronics/Dipole_folded.php). (http://www.dxzone.com/dx32420/folded-dipole-calculator.html). Accessed on 29 December 2016, 20:45 hrs, UTC . Please insert title or title URLs into your browser search box to read the full article. Comment: Folded Dipole Antennas are an interesting variant on the familiar half- wavelength dipole design.  The folded dipole offers more bandwidth than a classic half-wavelength dipole and can be fed directly with 300 ohm television twin lead , since the nominal impedance of this antenna runs between 280 and 300 ohms.  I've made several antennas of this type, using 300 ohm television twin lead for both the antenna elements and the feed line .  You can match the folded dipole antenna to your rig with either a 1/4 wavelength coaxial cable transformer or though a balanced antenna transmatch (i.e. "tuner"). A 4:1 current balun/"tuner" combination works fairly well, too. Use

Simple Ham Radio Antennas--Adding 80 metres to a 40 metre dipole

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If you're having trouble viewing this video, please insert this title link into your browser search box: https://www.youtube.com/watch?v=4kXz6fPFKY. This is post #995 in a continuing series called "Simple Ham Radio Antennas." Now that propagation is favoring the lower HF Amateur Radio Bands (160-40 meters), it may be a good idea to redesign your 40 meter dipole antenna to accommodate the 80 meter (3.5 MHz) band.  If you live on a small urban lot, extending your 40 meter (7 MHz) dipole antenna may present some challenges. In this video from Peter Parker (VK3YE), we learn how to use a 7 MHz dipole antenna on 3.5 MHz by adding end-loading coils.  Although this modification won't be as effective as a full-length 80 meter dipole and will be a bit narrower in bandwidth, it will get you on the air.  You may also use the 40 meter part of this modified antenna to work stations on the 15 meter (21 MHz) band, since the 40 meter elements will be usable as a 3/2 dipole on 1

Simple Ham Radio Antennas--Bobtail Curtain Antenna

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If you can't view the video, please insert this title link into your browser search box: https://www.youtube.com/watch?v=6dU2b0AHD1M. This is post #994 in a continuing series on Simple Ham Radio Antennas. The Bobtail Curtain Antenna is one of those projects that will take some time and effort to do correctly.  You may want to ask some of your ham radio friends to help you design, build, and erect this effective bidirectional, monoband, broadsided wire antenna for the HF Amateur Radio bands. Stan Gibilisco (W1GV) does a good job of explaining the theory, design, and use of this unusual antenna.  I used one of these antennas a few years ago during an ARRL Field Day event on Hawaii Island .  The 20 meter version of this antenna did an excellent job in capturing elusive Pacific Island contacts. In years gone by, many international shortwave stations used curtain arrays to direct their signals around the world.  If you want a different kind of antenna project, try the bobta

Simple Ham Radio Antennas--Center Connector for Dipole Antenna. Post #993

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Center Connector for Dipole Antenna (http://www.k4icy.com/dipoleconnector.htm). Accessed on 26 December 2016, 19:30 hrs, UTC . Author:  Michael A. Maynard (K4ICY). Please click title or insert title URL into your browser search box. Comment: Often times, the weakest part of your dipole antenna is the center connector. Depending on the materials used for the center support, the connector may be subject to extreme stress from holding up the weight of your long HF dipole and from the accumulated effects of severe weather . Although you can buy commercial versions of center connectors, it may be cheaper and more instructive to "roll your own." In this well-written article from Michael A. Maynard (K4ICY), we learn a simple, nearly foolproof method of making a center dipole connector that will survive  severe weather and support the weight of your full length dipole antenna. Although Michael calls the project "advanced", a little patience and attention to

Simple Ham Radio Antennas--Inverted "U" Antenna

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If you're having difficulty viewing this video, please insert this title link into your browser search box: https://www.youtube.com/watch?v=Q2UlV5V7Em4. This is post #992 in a continuing series of Simple Ham Radio Antennas. Here's another fascinating idea for those radio amateurs wanting to experiment with unusual, but effective HF antennas.  In this video, Stan Gibilisco (W1GV) explains the theory, design, construction, and use of the "Inverted U Antenna".  This antenna is particularly useful in portable or emergency operations.  The antenna is easy to build, inexpensive, and readily deployable. For the latest Amateur Radio news and information, please visit these websites: http://www.HawaiiARRL.info. https://oahuarrlnews.wordpress.com.. https://bigislandarrlnews.wordpress.com http://www.kh6jrm.info ( breaking news for radio amateurs). http://hawaiisciencedigest.com (latest science and technology news). Be sure to check the blog sidebars for addition

Simple Ham Radio Antennas--WB4IUY's Random Blog: Great Fan Dipole Diagram. Post #991.

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WB4IUY's Random Blog: Great Fan Dipole Diagram (http://wb4iuy.blogspot.com/2011/11/11/great-fan-dipole-diagram.html). Accessed on 24 December 2016, 21:45 hrs, UTC . Author:   Dave (WB4IUY). Please click title or enter the title URL into your browser to read the full article. Comment: If you want multiband HF coverage and can only erect one antenna for that purpose, you may want to consider the classic "Fan Dipole" which has served the Amateur Radio community for many decades. In this post, Dave (WB4IUY) describes a fan dipole created by YC8PVU which can cover several HF Amateur Radio bands with just one antenna using a single 50 ohm coaxial cable feed line .  You can add 160 meters, any WARC band , and event 6 meters using the same concept. This antenna doesn't require an antenna transmatch (i.e. "tuner") and automatically band switches.  Tuning is a bit critical, since the antenna elements are fairly close together.  But, as an all around

Simple Ham Radio Antennas--Vertical Dipole in Tree

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If you're having trouble viewing this video, please enter this title URL into your browser search box: https://www.youtube.com/watch?v=RI2_T-LeYEU. This is post #990 in a continuing series of Simple Ham Radio Antennas.  Here's another dipole antenna for those lacking the space to install a full-length horizontal HF dipole.  This antenna is vertical dipole fed with 450 ohm ladder line and arranged so that each element is suspended from a tall support such as a tree or telescoping fiberglass mast.   Stan Gibilisco (W1GV) does a good job of explaining the theory, construction, and use of this dipole variant. If the dipole is cut for the lowest frequency of operation and fed with ladder line, television twin lead, or  homemade balanced feeders, you will have a cheap, easily made dipole capable of covering several HF amateur radio bands .  An antenna transmatch (i.e. "tuner") with a 4:1 current balun is needed to match the feed line impedance to the impedance of