Notes on Ribbons, Cages, Parasites, and Lines
Broadband Coverage of the 80-75-Meter Band with AWG #12 Copper Wire
By L. B. Cebik, W4RNL (SK)

The chapter in The ARRL Antenna Book (9 in the 20th edition) is an excellent introduction to techniques for obtain full coverage of the 3.5-4.0-MHz amateur band, a 13% bandwidth as such things are reckoned. It is also a tribute to long years of work, analysis, and measurement by Frank Witt, AI1H, the chapter’s author. Nevertheless, the subject is not completely closed.

The premise for these notes is that we have an endless supply of AWG #12 copper wire. As well, we can support an 80-75-meter dipole at 90’ above average ground. Besides a little preliminary modeling in free space, we shall use these values as constants. Our goal is to create a dipole antenna that covers the entire band with an SWR of less than 2:1, using a reference impedance value that is appropriate for each situation that we examine. As we proceed, we shall recall a pair of matching techniques that employ combinations of transmission lines, including the system that Witt calls the transmission-line resonator or TLR. Toward the end, we shall do something that seems to have eluded authors to this point: we shall combine techniques for improved radiation and SWR performance.

Practical Antennas: Part 2.10
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: FM DXing in the Good Ole Summertime
By Robert Gulley, AK3Q

Balanced Transmission Lines
by Wes Stewart, N7WS

The increased number of HF ham bands, along with the decreased size of the average ham’s backyard, has made multiband operation of random-length wire dipoles an attractive option. This has brought about renewed interest in the use of balanced, parallel-wire transmission lines, commonly called “ladder line,” to feed these antennas. There is historical precedence for the use of these antennas; however, there are differences between earlier practice and today’s methods. Judging by on the air conversations and Internet group discussions, the “conventional wisdom” seems to be that ladder line has such low loss that it can be used in almost any situation without suffering any significant additional loss. Operating on the principle that if it sounds too good to be true, it probably is, I decided to take a closer look at the subject. This paper presents some of the results of my investigation. In it, I will attempt to correct some of the myths that surround the use of balanced transmission lines by contemporary radio amateurs.

The New Super-Delta: Part 1
By Edward J. Shortridge, W4JOQ

The Super-Delta matching configuration is a completely new method of broad banding radiators for use in some of the wider radio amateur bands, such as the 75/80-meter, 10- and 6-meter bands. It is well-suited to simplify wire radiators that require broad banding. The material costs are quite low and it is very easy to build. It is very versatile in its adjustments, permitting varying degrees of over-coupling, and allowing a 50-Ohm source match for various bandwidths. It requires a 50/50-Ohm balun, with two series capacitors that can be included in the balun housing.

A Radiant Barrier Antenna
By Grant Bingeman, P.E.