FEEDING ANTENNAS
Volumes 1, 2 & 3


FEEDING ANTENNAS
Volume 1:
About Baluns

ABOUT THIS BOOK SERIES
fter an RF signal has been generated in a transmitter, some means must be used to radiate this signal through space to a receiver. The device that does this job is the antenna. The transmitter signal energy is sent into space by a transmitting antenna; the RF signal is then picked up from space by a receiving antenna. The RF energy is transmitted into space in the form of an electromagnetic field. As the electromagnetic field arrives at the receiving antenna, a voltage is induced into the antenna (a conductor). The RF voltage induced into the receiving antenna is then passed into the receiver and translated back into the transmitted RF information.

The design of the entire antenna system is very important in a transmitting station. The antenna must be able to radiate efficiently so the power supplied by the transmitter is not wasted. An efficient transmitting antenna must have exact dimensions. The dimensions are determined by the transmitting frequencies. The dimensions of the receiving antenna are not so critical for relatively low radio frequencies. However, as the frequency of the signal being received increases, the design and installation of the receiving antenna become more critical. An example of this is a television receiving antenna. If you raise it a few more inches from the ground or give a slight turn in direction, you can change a snowy blur into a clear picture.

The feedline link between the antenna and the transmitting/receiving equipment is often the most mysterious part of the system. Therefore, this book assembles many articles from past issues of antenneX to provide the reader with a wealth of ideas that may enhance understanding and provide practical ideas for achieving goals that are common to feedline concerns.

In this 3-Volume book series, we primarily deal with the feeding aspects of an antenna system, which covers the area between the transmitter and the antenna.
The 200-page Volume 1 specifically deals with the use and application of various types of baluns, which happens to be a much more complicated component of the feedline than one would think whether one is a novice or expert. There are many different types, designs and methods of placement of the balun for the wide variety of antennas and their setups as well as environments. Numerous examples are shown with diagrams.

For Volume 2 about antenna networks, please scroll further down.

ABOUT THE AUTHORS - Volume 1
We have some of the finest authors and antenna experts whose works on which this book is based. We have attached a brief professional biography of each author by order of first appearance in the book: Click here for Authors

TOPICS COVERED IN VOLUME 1

Chapter

Title

Page #

 

INTRODUCTION  

I

Why an Antenna Radiates 15

II

The Effects of VSWR on Transmitted Power 32

 

USING BALUNS 40

1

Baluns, What Do They Do? 41

2

What is a Balun and Do I Need One? 45
3 The KISS Balun (Keep It Simple Stupid) 51
4 Build a Balun 54
5 Putting a Balun and a Tuner Together 57
6 Building Coax Choker Baluns 77

7

Common-Mode Current on Coax Feedlines

86

8

Baluns and Input Impedance Matching 93

9

The Balun and Complex Impedance Termination 102

10

Baluns & Antenna System Network Impedance Matching I 125

11

Baluns & Antenna System Network Impedance Matching II

132

12

Baluns & Antenna System Network Impedance Matching III 138

13

Baluns & Antenna System Network Impedance Matching IV 146

14

Balanced Feed and Feedline Radiation - Part I 156

15

Balanced Feed and Feedline Radiation - Part II 174

16

Need for Balun on Full Wave Loop

190

 

Other Publications 201

 


FEEDING ANTENNAS
Volume 2: Matching Networks

n Volume 2 of this book series, we shall discuss a wide variety of matching methods, including numerous designs, some frequency specific. Feeding an antenna is supplying energy to the appropriate element or elements in a series connection with the element, at a position on the element prescribed by the design. In pure terms, one places the energy source at this position. More realistically, one uses a transmission line between the actual energy source and the feedpoint position of the element. In some cases, one may place a matching network at the antenna terminals, with the transmission line connected to the input side of the network. For complex arrays with multiple fed elements, the feed system may use a combination of transmission lines and networks to establish specific relative current magnitudes and phase angles at each designated feedpoint.

There are many types of networks and some are antenna-type specific. In the chapters of this book many of these designs will be found, from basic to complex, some even experimental. One may have a great deal of fun experimenting with this useful antenna feeding component as well as the location of the feed connection.

Simply defined, an antenna network is a configuration of inductively and capacitively reactive components. The most fundamental arrangement is the L, with a series component of one type and a parallel or shunt component of the other type. More complex forms, such as PI and T networks are combination of L networks. Volume 2 delves into all of these in theory, construction and use.

More specifically, antenna networks have three main functions:

1. Networks can be designed to have different input and output impedance values and therefore are useful in transforming impedances. Special forms of them appear at the antenna terminals (such as the beta and the gamma match) to transform the antenna terminal impedance to a value that coincides with the desired main feedline impedance. The network antenna tuner in common use today is an example of a network used to transform a wide range on impedance values to the 50-Ohm value specific to most amateur radio and other equipment.

2. Networks act as high or low pass filters. When the series component is inductively reactance and the shunt component is capacitively reactive, we have a low-pass filter. If we reverse the positions of the reactance types, we have a high-pass filter. We may makes some network legs complex—usually in the form of series or parallel resonant circuits—to sharpen the filtration or to create band-pass or band-stop filter. (Some rudimentary audio filters use combination of one reactive leg and one resistive leg.)

3. Networks always show at the output side a change in the phase angle of the AC (or RF) signal. This phenomena is useful in the development of phased arrays that are dependent for their directional properties on the relative magnitude and phase angle of the currents at the respective feedpoints of the elements composing them.

ABOUT THE AUTHORS - Volume 2
Again, with this Volume 2, we have some of the finest authors and antenna experts whose works on which this book is based. We have attached a brief professional biography of each author by order of first appearance in the book: Click here for Authors

TOPICS COVERED IN VOLUME 2

Chapter

Title

Page #

 

   

17

Matching Antennas to Coax 19

18

Wideband Matching: Approaching a Theoretical Limit 31

19

The Conjugate Match

68

20

Antenna Tuning & Conjugate Match, Another Look 76

21

Automatic Commutation - Matching Device 90
22 Mobile Matching Networks 110
23 Universal Matching Device, An ATU Plus Artificial Ground 116
24 Series Matching - A Review 130
25 The Quarter-Wavelength Matching Section 140

26

Stub Matching Using the Smith Chart

159

27

Antenna Impedance Matching Using Stubs 171

28

Transformer Magnetic Coupling & Matching 185

29

Preliminary Notes on the Gamma Match 197

30

Universal ATUs for HF Ranges

224

31

The ATU - Simple Matching Circuits 238

32

Surplus Equipment Makes Simple L-Match ATU 246

33

The Quad Phaser Network: Part 1 254

34

The Quad Phaser Network: Part 2 267

35

Matching Devices for 24/28 MHz

290

 

Other Publications 296

 


FEEDING ANTENNAS
Volume 3:
Transmission Lines
n Volume 3 of this book series, we point our focus toward another important component of the connection between the transmitter or receiver and the antenna — something that looks so simple but its behavior can baffle — it's just a wire, right? Wrong! One may have the best of equipment and antenna, but if the impedance is not properly handled, one may as well have cheap hardware. Without optimizing the impedance of a rig's setup, it can be a frustrating experience trying to make decent contacts, if any. There are many types of "wires" (cables) to select and usually one or more best applies to the antenna's performance.

A frequent and usually protracted topic of discussion on our antenna-discussion forum is about transmission lines. There always seems to be numerous opinions about this area, coupled with confusion and misinformation. It’s an important part of the antenna system and a challenge always faced with setting up a new system, antenna design or rig. Even the old hands find a good bit of experimenting and tweaking usually necessary to get thinks working right and then, optimized as best possible.

I usually encourage members of our writing team to focus their article submissions on this topic from time to time as well. I have always noted from the discussion held on the forum, most explanations are still followed by more questions by many of this bright group. It never seems to be explained completely enough at times, which is why it keeps coming up again and again.

Along with other authors, including L.B. Cebik in this 3rd volume, as Editor/Publisher Jack L Stone, I also make another contribution to the subject of transmission lines hoping to convey yet another simple way to approach the topic based on information published by antenneX.

Volume 3 also includes a companion calculator program in GWBasic, "Line Impedance" where one can input their own unique values for an antenna system. As noted below, another Transmission Line Analyzer program is available for purchase separately.

TOPICS COVERED IN VOLUME 3

Chapter

Title

Page #

 

   

36

Transmission Lines: An Introduction 9

37

Transmission Lines: Definitions and Terminology 21

38

Transmission Line Theory

26

39

Power flow on transmission lines 43

40

Understanding Feedpoints 49
41 The Dipole and the Coax 67
42 Radiating and Transmission-Line Currents 90
43 Common-mode Current 161
44 How to See Your Feeders 140

45

Home-Brew Parallel Transmission Lines

224

46

Series and Parallel Coaxial Cable Assemblies 244

47

Hybrid Transmission Line Stubs 261

48

Transmission-Line and Tuner Calculation Aids 289

49

Wide-Band 50/75-Ohm Coax Feed System for Low HF Band Dipoles & Vees

326

50

Calculating Input Values from Load Values on a Transmission Line 350

51

Calculating Voltage, Current & Impedance on a Transmission Line 372

 

Other Publications 378

 


HOW TO ORDER THESE BOOKS
These special books are available only in eBook version either on CD-ROM or Download. The eBook is in the popular PDF format and requires the Adobe Acrobat Reader 5.0+. The eBook may be purchased by immediate download directly from this website, or shipped to you on CD-ROM. You may order your eBook directly online from our own Secure Website, or by FAX, telephone or postal service. Links to the ORDER FORMS are provided here.

Also, a useful companion TLA utility program may be ordered separately from the links below.

 

VOLUME 1

Catalog #
Vol 1

Regular
Price

eBOOK CD-ROM ORDER FORM BOD-010 $24.95 USD
eBOOK DOWNLOAD ORDER FORM BDL-010 $22.95 USD

VOLUME 2

Catalog #
Vol 2

Regular
Price

eBOOK CD-ROM ORDER FORM BOD-011 $26.95 USD
eBOOK DOWNLOAD ORDER FORM BDL-011 $24.95 USD

VOLUME 3 (Includes a Line Impedance Calculator)

Catalog #
Vol 3
Regular
Price
eBOOK CD-ROM ORDER FORM BOD-012 $28.95 USD
eBOOK DOWNLOAD ORDER FORM BDL-012 $26.95 USD

3-VOLUME COMBO at 20% discount
(Includes the same Line Impedance Calculator above)

Catalog #
Vols 1, 2 & 3

3-Volumes
20% Discount

eBOOK CD-ROM ORDER FORM BOD-013 $64.65 USD
eBOOK DOWNLOAD ORDER FORM BDL-013 $59.95 USD
     

Order Separate Companion Impedance Line Utility (different than above)

Catalog #

Price

Transmission Line Analyzer for Windows on disk SWOD-001 $19.95 USD
Transmission Line Analyzer for Windows download (save $2.00 & S&H) SWDL-001 $17.95 USD