Showing posts from January, 2017

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

5/8 Wave Vertical Antenna Calculator ( 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.

If you're having trouble viewing this video, please insert this title URL into your browswer search box: 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: ( breaking news for radio amateurs ). Other sites you may enjoy: (science and technology news for radio amateurs). (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? ( 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

Online Dipole Antenna Calculator. Post #1026.

Online Dipole Antenna Calculator ( Accessed on 28 January 2017, 23:50 hrs, UTC. Author:  Kitchener Waterloo Amateur Radio Club. Please click link or enter title URL into your browser search box to read the full article. Comment: Here's a handy and easy-to-use dipole antenna calculator from the Kitchener Waterloo Amateur Radio Club.  Just plug your desired center frequency into the blank provided, and you'll get the total length of your dipole, as well as the length of each dipole element.  The measurements are presented as feet. The computer generated length will give you a good starting point for making your simple dipole antenna.  You may have to trim wire to keep SWR low or to accommodate the antenna to the layout of your property. The choice of feed line is up to you.  According to this post from the Kitchener Waterloo Amateur Radio Club, a variety of feed lines is available: "The half-wave dipole is

Full Wave Loop Antenna Calculator. Post #1025.

Full Wave Loop Antenna Calculator ( Accessed on 28 January 2017, 05:25 hrs, UTC . Author: Comment: While a full wave loop antenna can be cumbersome on the lower HF bands (160 and 80 meters), they are manageable  from 40 meters through 6 meters.  Despite their size, full wave loop antennas are generally quieter than dipole antennas and show some gain broadside to the plane of the loop (approximately 2dB).  If you feed the full wave loop with 450 ohm ladder line , 300 ohm television twin lead, or homemade balanced line , the loop will be usable on all Amateur Radio bands from the design frequency and up. This article provides simple formulas for full wave loop antennas in both feet and meters.  If you prefer coaxial cable feed lines, the article gives lengths for matching 75 ohm cable to 50 ohm cable.  You can also plug the frequency in MHz into the blank space provided and push the "calcul

A Low Cost Multi Band Antenna.

A Low Cost Multi Band Antenna ( Accessed on 27 January 2017, 02:10 hrs, UTC. Author:  Len Paget (GMO0NX). Please click link or insert title URL into your browser search box to read the full article. Comment: How would you like to build a simple, inexpensive, trap dipole antenna that covers the Amateur Radio 80, 40 ,20, 15, and 10 meter bands without an antenna transmatch ("tuner")?  You can if you follow the instructions posted by Len Paget (GMO0NX).  Len's antenna is based on a proven design by W3DZZ. This trapped dipole is shorter than most monoband dipoles and requires two simple coaxial cable traps to make the antenna system work. Les says the SWR for each band is below 2:1 and often is better than 1.5:1.  You can configure the trapped dipole in a variety of ways, from a basic flat-top dipole to an inverted Vee, depending on the space available. The article has plenty of diagrams and pictures to help y

Get Ready for the Solar Minimum. Post #1023.

Title:  Get Ready for the Solar Minimum. Authors:  Steve Ford (WB8IMY), Joel Hallas (W1ZR), and Curt Luetzelschwab (K9LA). Source:  "QST", February 2017, pp.48-51. Comment: While I was searching for low-band HF antenna ideas (160 through 40 meters) suitable for our changing propagation, I ran across this article in the February 2017 issue of "QST"-- the official membership journal of the ARRL. Steve Ford (the "QST") editor does a good job of describing how our operating habits will change as the Sun reaches solar minimum.  According to Steve, "The solar minimum will have its greatest impact on the high- and medium-frequency bands, and we're already seeing hints of what is to come." In most cases, higher HF bands such as 12 and 10 meters will suffer the most fluctuation.  Propagation won't be entirely dead above 24 MHz, but it will rely on "sporatic E" to send signals to distant points.  As any 6-meter enthusiast will

Simple Ham Radio Antennas--Ground Plane Antenna Calculator

Ground Plane Antenna Calculator ( Accessed on 24 January 2017, 20:30 hrs, UTC. Please click link or enter the title URL into your browser search box to read the full article. Author:  Glynn "Buck" Rogers (K4ABT). Comment: Ground plane antennas are useful for a variety of amateur radio operations from the upper HF bands (20 meters through 10 meters) to the 6 meter, 2 meter, and 70 centimeter amateur radio bands. This calculator from Glynn "Buck" Rogers (K4ABT) of BUXCOM ( is designed "to give the vertical length of a quarter wave ground plane antenna and the length of each of the four radials for the selected frequency you have entered." Element and radial lengths will be given in terms of meters, feet, and inches.  Some pruning of wire/rod lengths may be needed to keep SWR below 2:1.  A handy, useful guide for the antenna experimenter. For the latest Amateur Radio news

Simple Ham Radio Antennas--Antennas for portable operation. Post #1021.

Antennas for portable operation ( Accessed on 24 January 2017, 00:45 hrs, UTC. Author:  MyHyEndFed Antennas. Please click link or insert title URL into your search box to read the complete article. Comment: A short, basic tutorial on the types of antennas best suited for portable operations.  The author does a good job of explaining the pros and cons of portable antennas ranging from verticals to half-wavelength dipoles. Although there is no "perfect" antenna for portable or emergency use, this post recommends the classic end-fed half-wavelength antenna with a matching unit as the most cost effective and simple to erect antenna for field operations. The original concept of the end-fed half-wavelength antenna goes back as far as 1928 when "QST" ran a series of articles on this multiband HF antenna. According to the MyHyEndFed Antenna manufacturer, the easily assembled end-fed half-wavelength antenna is

Simple Ham Radio Antennas--Moxon Antenna Calculator. Post #1020.

Moxon Antenna Design Calculator ( Accessed on 23 January 2017, 02:45 hrs, UTC . Author:  Paul H. Evans (W4/VK9KF). Please click link or insert title URL into your browser search box to view the calculator. Comment: Thanks to Paul H. Evans (W4/VK9KF), you can now design your own Moxon Antenna online by simply plugging in wire diameter and resonant frequency . According to Paul, Moxon Antennas are fairly simple to make from commonly available materials and do very well on a wide selection of amateur radio bands . I've often assumed, incorrectly, that the popular Moxon rectangle antenna is strictly a HF antenna.  However, the small size and special far field pattern of this antenna lend it to some interesting VHF applications, including 6 and 2 meters. Paul's calculator derives from a public domain BASIC program written by L.B. Cebik (W4RNL)(SK).  That program can be found here:

Simple Ham Radio Antennas--A Simple 40 Meter Vertical For Field Day. Post #1019.

A Simple 40 Meter Vertical for Field Day ( Accessed on 21 January 2017, 23:45 hrs, UTC . Please click link to read the full article. Author:  Gary C. Sutcliffe (W9XT). Comment: The ARRL Summer Field Day is fast approaching (last full weekend in June) and now's the time to build that portable antenna for your "Field Day" experience. In this article from Gary C. Sutcliffe (W9XT), we learn how to design, build, and use a simple 40 meter vertical antenna for your remote operation.  The antenna is simplicity itself, with a fiberglass mast, a tapped coil, 32.8 ft/10 meters of household wire, a ground stake, and two elevated counterpoise wires about 4-ft/1.21 meters above ground comprising the entire system.  The feed line is a convenient length of 50-ohm coaxial cable , with any excess cable being wound around a plastic coffee "can" to serve as an rf choke.  A great and effective design that will get

Simple Ham Radio Antennas--How to construct and use a Buddipole Antenna

If you can't view this video, please insert this title URL into your browser search box:  This is post #1018 in a continuing series on "Simple Ham Radio Antennas." The Buddipole Antenna kit is a versatile portable antenna that can be configured in several ways, depending on band conditions and the location of your portable station. In this video, K2EFG takes us step-by-step through the unpacking, assembly, and use of this portable antenna.  This video tutorial shows us how to build a Buddipole Antenna for use on 20 meters.  The explanation is simple, direct, and uncomplicated.  The Buddipole Antenna system can be stored in your shack or in your vehicle for portable or emergency operations. For the latest Amateur Radio news and information, please visit these websites: (breaking news fo

Simple Ham Radio Antennas--40m mini portable End Fed Half Wave Tuner. Post #1017.

40m portable End Fed Half Wave Tuner Author:  VK5ZVS. Accessed on 20 January 2017, 05:55 hrs, UTC . Please click title link or insert title URL to read the article. Comment: One of the most popular HF antennas for portable or emergency use is the EFHW (end fed half wave).  The antenna is cheap, easy to make, and can be stored easily in your home or vehicle.  However, one of the drawbacks to the EFHW is the rather large SWR presented to our amateur radio transceivers which usually have a nominal impedance of 50 ohms. The impedance issue can be mitigated with a simple antenna transmatch (i.e. "tuner").  In this post, VK5ZVS shows us how to make an inexpensive "tuner" from commonly available parts.  The heart of the device is a tapped coil (31 turns) wrapped around a T200-6 core and a 56pF capacitor.  VK5ZVS provides helpful photographs and a simple schematic diagram of his "tuner."  This