The ARRL Antenna Anthology

156 Pages·2018·40.62 MB·English

THE ARRL $4.00
/

The ARRL
Antenna Anthology
Edited by
Marian S. Anderson, WB1 FSB
American Radio Relay League, Inc.
Newington, CT 06111
Copyright © 1978 by
The American Radio Relay League, Inc.
Copyright secured under the Pan·Amerlcan
Convention
International Copyright secured
This work is Publication No. 36 of the Radio
Amateur's Library, published by the League.
All rights reserved. No part of this work may
be reproduced in any form exc,ept by written
permission of the publisher. All rights of
translation are reserved.
Printed in USA
Quedan reservados todos los derechos
Library of Congress Catalog Card Number:
78·71955
$4.00 in USA
$4.50 elsewhere
Foreword
What type of amateur antenna best suits your needs?
Does the available space on your property permit the in·
stallation of an effective DX antenna? Is there a com
promise antenna system that will provide acceptable
results over short and long distances while being
reasonable in price and modest In complexity? No doubt
you have come to grips with these matters repeatedly
since obtaining your amateur license. So, where does one
turn to find the answers to these sometimes perplexing
questions? What one pre-eminent source might one consult
among all of the antenna booklets published for
amateurs? Why, QST, naturally!
This anthology contains what the ARRL hq. staff con
siders the best of the QST antenna articles and theory
presentatio'ns in recent years. The contributions of
numerous amateur authors and designers are contained in
this volume for your convenience. This publication was
developed not only to serve as a compilation of good
articles, but to reach those amateurs who do not have
access to past issues of the League's official monthly
journal, QST.
The editors of this booklet have attempted to select the
types of antennas that have greatest appeal to those who
like to construct their own radiators, and for the many
amateurs who can't justify the expense of purchasing
commercial counterparts. A book of this type contains
something for everyone who enjoys building and ex·
perimenting with antennas. But, if you aren't a builder you
will still enjoy the hours of interesting reading provided by
these works.
We wish to extend our gratitude to those QST authors
whose articles have been selected for publication in this
volume. Their enthusiasm, ability and generosity typifies
clearly what Amateur Radio is all about. Should you have
some original antenna ideas of proven performance, send
an article to the ARRL, describing your work. Not only
may your story be published in QST - it might appear in
a future edition of this book.
Richard L. Baldwin, W1 RU
General Manager

Contents
1 Vertical Antennas
Page 7
2 Yagi Antennas
Page 41
3 Quad Antennas
Page 53
4 Miscellaneous Antenna
Types
Page 76
5 Antenna Theory and
Test Methods
Page 100
Index
Page 150

Chapter 1
Vertical Antennas
One of the most practical antennas for use the virtues of vertical antennas extend type of antenna.
where limited space exists is the vertical. beyond the foregoing considerations: This chapter contains reprints of some
This type of antenna is particularly useful to "Verticals," as they often are called, are popular vertical-antenna systems that have
amateurs who live in dense urban areas relatively inexpensive, easy to erect and appeared in QST during recent years. For
where city lots are traditionally small. The are capable of performing well for lo the most part, the presentations contained
same general restriction prevails for those cal (stateside) and DX work. A vertical herein have been "lifted" in their entirety,
who dwell in apartment buildings. In such antenna exhibits a low angle of radia thus making it unnecessary for the reader to
locations it is often easier to go "up" with an tion when worked against a good ground research the original articles for additional
antenna than to erect one horizontally. But system. This makes it an effective DX information.
A Two-Band Vertical for the Novice
Build this inexpensive Novice antenna. It is easy to construct and is made from
readily available materials.
K nowing of a Novice who had space high, the vertical would need strength, so into the lower piece to make the overall
problems, the author set out to design an the writer thought of steel tubing, but that antenna length about 31 feet, I 0 inches
antenna for him that could be used on 40 was much too expensive. With conduit (9. 70 m). Because of its large size, all the
and 15 meters. His previous antenna was a there aren't enough sizes offered, and that work must be done while the antenna is
horizontal "V" whose performance wasn't left only one more material - aluminum
worth the time it took to put it up. Because tubing. The latter comes in just about any
of his narrow property, the angle between size desired, and the author had no trouble
the two wires was only around 40 degrees, in findingjust what he wanted. Going to the
no doubt causing considerable signal nearest aluminum dealer, the author found
cancelation. Horizontal antennas were his stock to be more than ample.1
ruled out, so the best antenna for him was a In order to keep the cost minimal, the
vertical. author decided to make the base piece from
Knowing (or caring) little about multi I-inch (25-mm) diameter thin-wall tubing.
band trap-loaded antennas, it was decided Into l 2feet(3.66 m) oft his was inserted a 12-
the simplest antenna would be a quartcr foot piece of 7 /8-inch (22-mm) diameter
wavelength vertical on 40 meters. After a thin-wall tubing. This piece was telescoped
little paper work. and using formulas given 2 feet (0.610 m), then bolted and clamped
in The ARRL Antenna Book, the correct (after the end had been slit twice by a pair of
length would be3 I feel 10 inches(9.70m) for tin snips). It was necessary to use hose
7.175 MHz. This length would also work as clamps on the tubing because the galvanized
a 3/4-wavelcngth antenna on 15 meters, bolts didn't provide a good bond between
providing two-band coverage. However, a the pieces. The top section was 13-1/2-foot
32-foot (9. 75-m) vertical antenna made (4.11-m) piece of 3/4-inch (19-mm) diame
roof-mounting too difficult! Mounting the ter thin-wall tubing inserted far enough
vertical to the side of the house alleviated
many guying and support problems.
Materials
'[Editor's Note: TV mast material is also well suited Here is the base mount, installed on the side of the
The first concern was what to use for
for verticals and comes in 10-foot (3.05-m) lcng1hs. house. The two white wires coming out from the
antenna materials. Being almost 32 feet either steel or, preferably, aluminum.) base are the radials.
Vertical Antennas 7
HOLES FOR HOLE FOR
WOOO SCREWS, S0-239
COUNTERSUNK FITTING
HOLE FOR 0
HOLES FOR \bBO LT HOLES FOR
WOOO SCREWS, 00 000 BOLTS USEO
COUNTERSUNK TO SECURE )IE THIS BRACKET SHOULD SE
RADIALS MADE SO THAT IT WILL
0 HOLD THE ANTENNA AWAY
FROM THE HOUSE THE
SUPPORT BRACKET SAME DISTANCE THAT IT
IS AT THE BASE 8RACl<fl.
1/8-(3mrn)
SHEET
ALUM.
Fig. 2 - Details for the support bracket.
LARGE
1 3"(76mm)-
/~~~~~~T
[GJ
3/4"(19mm) limited, two radials were all that could be
PINE --......
ANTENNA used. Ideally, the most pe·rfectsystem would
consist of a metal disk, one quarter
wavelength in radius, buried a few inches
below the earth's surface, but this approach
(229mm)D is rather impractical! But if the antenna was
0 0 to be erected in an area away from buildings,
and guyed, a ground system could be made
CERAMIC •eEEHIVE• of chicken wire or other similar material.
INSULATOR OR
JI __ However, the more radials, the better the
1:::::::===tm===:~;:i SIMILAR
artificial ground. Also, they should be laid
/ out in as nearly a spoke-like pattern as
REMAINING PORTION OF possible. Hy-Gain recommended for their
BOLT CAN BE USED TO A VQ series antennas that a radial system be
ATTACH RADIAL WIRES
used consisting of at least two radials for
each band used. However, for this
Fig. 1 - Details for making the base-mounting section of the vertical.
installation the 40-meter radials operate on
their third harmonic at 15 meters, requiring
but one set of wires. 2
lying on the ground. Then, the antenna section). A suitable cap was mounted on top The length specified makes the antenna
must be disassembled and put up piece by of the antenna to keep out moisture. resonant at about 7175 kHz on 40 meters.
piece. (Do not attempt to put the antenna On 15 meters, at the third harmonic, the
up in one piece! While the weight isn't Tune Up antenna is resonant at about 21,425 kHz,
excessive, the tubing cannot stand the RG-58/ U coax was then connected but powerwasappliedaslowas21,l05 kHz,
strain.) between the transmitter and antenna with
an SWR bridge in the line, and power was
Putting It Up applied at 7175 kHz.TheSWR was found to '[Editor's note: Actually, any radials, ·regardless of
length, will help the performance of the system. Also
The original base bracket was made from be 3: I. This was without any ground system when used on 15 meters, the antenna would be thre~
3/4-inch (19-mm) pine, but during the first on the antenna. In order to obtain a better quarter wavelengths long with low-impedance
rain the wood got wet and the bracket match and reduce the SWR, it was apparent feed, approximately 50 ohms. However, the angle of
turned out to be a very poor insulator. So that a ground system was required. radiation from the antenna will be bigber than that
of a quarter-wavelength vertical.]
the unit was redesigned to use two pieces of According to The A RRL Antenna
I /8-inch (3-mm) thick sheet aluminum, a Book, two methods of making a suitable
large grommet, and a ceramic standoff ground system can be used. One way is to
insulator (see Fig. 1). connect the coax outer shield directly to
Assembling the two-band vertical was ground at the base of the antenna, via a
quite simple. First, a 4-foot ( 1.22-m) stake ground rod. However, this doesn't work
was driven into the ground about 2-1 /2 feet too well unless the soil is extremely
(0. 76 m), and about four or five inches (I 02 conductive (his wasn't). The other method
or 127 mm) away from the side of the house. is to make up some sort of artificial ground
Next, the bottom section (with the bracket in the form of radials.
attached) was slipped over the stake and The author cut a radial from some surplus
tightened in place with the U bolts. Then the wire to the same length as the vertical
second se.ction was inserted into the first, section, attached the radial. to the base plate
clamped and bolted in place. A support and the SWR dropped to 2: I. Unknown to
bracket was made from scrap aluminum, the author at the time, The Antenna Book
and a large grommet was installed on it to says that the radials should be 2.5 percent
insulate the antenna from the brace(see Fig. longer than the vertical itself, so actually,
2). This assembly was then attached to the they should have been made 32-fcet 7-3/4-
side of the house (near the gable) with wood inches (9.95-m) long. A second radial,
screws. Last, the third section was forced similar to the first, was attached and the
through the grommet in the second bracket, SWR dropped further (to about 1.4:1).
and was then inserted into the second piece When the soil was wet, such as after a rain or
and clamped. (If adjustment of resonance is after watering, the SWR takes a nosedive to
desired, it is better not to bolt the final less than 1.2: I. Since the property space was The support bracket, as described in Fig. 2.
8 Chapter 1