MYY-TRI
By L. B. Cebik, W4RNL (SK)

“MYY-Tri” stands for a Moxon rectangle-Yagi-Yagi tri-band array for 20, 15, and 10 meters. We may pronounce the label as “My Try.” In effect, the antenna that we shall examine in these notes is a design exercise aimed at seeing if I could apply some of the principles recorded and illustrated in the 6-part series, “Designing Multi-Band Parasitic Beams” to a 3-band array. The series focused on 2-band beams in order to keep the principles as clear as circumstances permitted. However, most amateurs wish to cover at least three bands with their directional arrays. So I started working on a tri-band beam using a Moxon rectangle for 20 meters, with linear Yagi elements for the two upper bands. The result turned out to be two designs rather than just one, and there are at least 5 notable variations in all.

Practical Antennas: Part 2.2
By Marcel H. De Canck, ON5AU

The ionosphere plays a tricky but an important role to our radio communications, and there is very little we can do about it. But there is plenty you can do about having a good and efficient antenna system. Yes, antenna system, it’s not the antenna itself but the whole part as transmission line, and matching properly the transceiver and the antenna to the transmission line. It is a breath-taking concept that a simple length of wire or rod or tube can transform electrical energy into invisible radio electro-magnetic waves that can cross the space at the speed of light.

How does an antenna system works? Why does the antenna radiate electro-magnetic waves? These questions I heard many times and the answers are not given with few words. Never-the-less, many books and some of great weight and complexity have been written about antennas and many antenna types have been developed and build. Often it is not comprehensive to the layman to fully understand the whys and hows of the radiation capabilities of an antenna and these counts even for the simplest ones like a dipole or a groundplane. Also I often hear many times misconceptions about antenna properties and characteristics. To start with, understanding why and how a simple antenna effective radiates will be explained in a clear view. The dipole is the best antenna to do that and once the secrets of the dipole characteristics and properties are fully understood it will be much easier to have a clear insight of the hows and whys of more complicated antennas.

The first episodes will handle completely about antenna fundamentals mostly with the half wavelength dipole as study example. The dipole is also often a part element of more complicated antennas such as a Yagi and others. In particular for the low frequency bands, the dipole is used by many radio amateurs as transmitting or receiving antenna and its many practical installations and shapes will be fully studied and explained in a chapter later on. In fact many other antenna types will become subject to explanation as the antenna story develops.

NewcomerNotes: Antenna Efficiency, Bandwidth and Gain
By Robert Gulley, AK3Q

All of the above factors are discussed in depth in this month's article.

THE OCF FD4 (FD3) WINDOM ANTENNA
By Frits HV Geerligs, PA0FRI

The 4-band (10-20-40-80) Fritzel model FD4 is a special version of a Windom antenna. It is a half-wave long on the lowest frequency, and is fed from a coax cable through a transformer inserted in the wire at one-third from one end. It so happened I was experimenting with the same system of antenna and trying to determine the best dimensions. We also discuss a 5-band version of the FD4 or 80-40-20-15-10. Another version can handle 160. The Fritzel FD3 is a half-size version of the FD4, which resonates on 40, 20 and 10-m. 15-m, can be added as described in this article.

6-10M & 10-20M L-pole Antennas
Broad Banding and Creating Dual-Band Antennas
By Edward J. Shortridge, W4JOQ

The broad banding of antennas using "L" pads consisting of a series inductance with a shunt capacitance have been used in various forms for many years. They have been modified to substitute coaxial cables for any discrete components, and their use can be found in many types of antennas.

In the latter part of the year 2000, I began modeling using "L" pads, but the basic pad was insufficient to control the shape of the SWR across the entire bandwidth being considered. Therefore, I modified the configuration to include a series matching line on the input, and included a discrete inductor paralleling the shunt capacitor.

Yagi Antenna Elements Boom Correction
By Dragoslav Dobričić, YU1AW (Serbia)