Posts

Doublet aerial for HF amateur ham radio short wave bands

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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=8ZmyvtMvEGY. This is Post #1031 in a continuing series on "Simple Ham Radio Antennas." This is another great, easy-to-understand antenna tutorial from "Ray" of the "Radio Workshop." If you can only erect one antenna to cover the 80 through 10 meter amateur radio bands, then the classic "doublet" antenna is your best best to get reasonable multiband HF performance at a modest cost.  As Ray explains, a "doublet" cut for 3.500 MHz (total length of 133.71 feet/40.76 meters) will perform well on amateur radio frequencies between 3.500 MHz through 29.999 MHz if you feed the dipole antenna with balanced line (300 ohm television twin lead, 450 ohm ladder line , or homebrewed 600 ohm balance line).  Run the balanced feed line into a 4:1 current balun and connect the balun to your antenna tran

Ham Radio, an ununsual stealth antenna one foot above ground. Post #1030.

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An unusual stealth antenna one foot above ground (http://www.southgatearc.org/news/2017/february/an-unusual-stealth-aerial.htm#.WJJMLv8rLIU). Accessed on 01 February 2017, 21:35 hrs, UTC . Author:   John Allsopp (G4YDM). Please click link or insert title URL into your web browser to read the full article. Comment: For those of us who live in deed-restricted homes or "space challenged" urban lots, the use of a full length dipole or vertical antenna is often out of the question. Your antennas of choice will be limited to what can't be seen or removed quickly as the situation demands.  Often, your antenna will be a highly compromised version of a dipole, vertical, or even a magnetic loop.  You can certainly make contacts with these antennas, but what you need is a full performance dipole on a deed-restricted lot.  Impossible? Not really, if you follow the instructions presented in this post from John Allsopp (G4YDM). According to John, just build a standard le

5/8 Wave Vertical Antenna Calculator. Post #1029.

5/8 Wave Vertical Antenna Calculator (http://www.qsl.net/w4sat/five8th.htm). Accessed on 01 February 2017, 04:50 hrs, UTC. Author:  W4SAT. Please click link or insert title URL into your browser search box to read the full article. Comment: You can design, build, and operate your own 5.8 wavelength vertical antenna by using this simple javascript antenna calculator. An antenna matching device, such a wire-wound coil, must be added between the vertical antenna element and the coaxial cable feedline so that the antenna can match the impedance of the coax feedline.  The addition of 3 to 4 quarter wavelength radials will make the antenna more efficient and easier to adjust. As you can guess, the 5/8 wave antenna is a bit more complex to build than the simple ground plane antenna using a 1/4 wavelength vertical element.  So, why go to all the trouble of building the 5/8 wavelength vertical antenna?  W4SAT gives us several reasons to build this larger vertical antenna: "So

Installing an End Fed HF Antenna. Post #1028.

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If you're having trouble viewing this video, please insert this title URL into your browswer search box: https://www.youtube.com/watch?v=ocPxYkOTD24. Interesting video from VK5STU on how to install an end fed HF antenna in a space restricted area.  Despite a few frustrating moments, the antenna and its "squid pole" supports (fiberglass masts) were installed without incident. Hopefully, this video will give you some ideas on how to design, build, and install an end fed HF antenna. For the latest Amateur Radio news and information, please visit these sites: http://www.HawaiiARRL.info. https://oahuarrlnews.wordpress.com. https://bigislandarrlnews.wordpress.com. http://www.kh6jrm.info ( breaking news for radio amateurs ). Other sites you may enjoy: http://hawaiisciencedigest.com (science and technology news for radio amateurs). https://hawaiiintelligencedigest.com (trends in geopolitical intelligence, strategic forecasting , terrorism, and cybersecurity).

Ground System Performance for HF Verticals, Post #1027.

Ground System Performance for HF Verticals, Part 4, How Many Radials Does My Vertical Really Need? (http://www.dxzone.com/qsy32482-radials-on-vertical-antenna). Accessed on 30 January 2017, 00:10 hrs, UTC. Author:  Rudy Stevens (N6LF). Please click link or insert title URL into your browser to read the full article. The article takes you to a downloadable link which displays all five pages of the antenna study.  The original article appeared in "QEX", May/June 2009, pp.38-42. Commment: One of the drawbacks to most 1/4 wavelength verticals is the need for an extensive ground radial or counterpoise system.  In this exhaustive study done by Rudy Stevens (N6LF), we get an idea of how important ground radials are for the efficient operation of a 1/4 wavelength vertical antenna. Rudy based his experiments on the pioneering work of the late Jerry Sevick, with results closely matching those of Sevick's original investigations.  Rudy's analysis offers several conclusi