How Antennas Work
Introduction
Every active ham uses an antenna. But how many hams can say that they really understand what happens when they apply RF to their antenna? The RF signal somehow leaves their antenna and is picked up by an antenna on the other end of a QSO, but to many hams this is a mysterious process.
Antenna theory sounds like a boring, dry subject, but understanding how an antenna radiates, how it interacts with ground and understanding something about antenna polarization is central to being able to answer the question that most hams really have when they think about antennas -- "Which antenna is best?"
This page has pointers to a number of articles that have appeared in QST over the years on antenna theory. Reading these articles will help you answer that question for your station, and for your friends.
The article, "Why an Antenna Radiates" answers the question about just why an antenna radiates when an RF signal is applied to its feed point. See also the list of other articles about antenna theory.
Additional resources
Articles
Note: Some of the following articles are in Adobe Portable Document Format (PDF) files. To view and print these files, you'll need a copy of Adobe's Acrobat Reader program. (Version 3.0 or later required). More information here.
- Why an Antenna Radiates
QST November 1992, pp. 59-63
You don't have to know how an antenna works to use one, but getting a handle on this subject can deepen your understanding of radio. Here's a searching look at the mysterious process by which our antennas hurl energy from Here to There.
- Which HAM Radio Antenna is the Best Choice for Point to Point Communications
by 10th grader Heather Cox (KB8VYQ)
Received award at the 42nd Annual Southeastern Michigan Science Fair 2000
- An Analysis of the Balun (1,835,322 bytes, PDF file)
QST April 1980, pp. 19-21
What does a balun do for you? What happens if you don't use one? Does a balun really make a difference?
- The Effect of Continuous, Conductive Guy Wires on Antenna Performance (814,978 bytes, PDF file)
QST August 1993, 22-24
Radio amateurs have long worked to preserve antenna patterns by installing segmented, nonresonant guys. Now, computer modeling reveals that unbroken guys can work just about as well.
- "My Feed Line Tunes My Antenna!" (341,217 bytes, PDF file)
QST November 1991, pp. 33-35
A tutorial - Everything you should know about feed-lines.
- Match Bandwidth of Resonant Antenna Systems (589,979 bytes, PDF file)
QST October 1991, pp. 21-25
Did you know that deliberately mismatching an antenna to it's feed line can increase its SWR bandwidth? Here's how it works.
- Coaxial Cable -- The Neglected Link (826,822 bytes, PDF file)
QST April 1981, pp. 28-31
Is a better grade of coaxial cable worth the price difference? This analysis of the importance of shielding in coax lines explains why the answer is "Yes!"
- Combined Vertical Directivity (506,839 bytes, PDF file)
QST February 1981, pp. 19-21
You need a low radiation angle for DX and a high angle for short skip. Most of us shoot for maximum antenna height and hope for good results. Learn how to calculate the vertical radiation patterns for various heights.
- Vertical Array Analysis (356,399 bytes, PDF file)
QST February 1981, pp. 22-25
You can determine the radiation pattern of an experimental phased array before building it. A computer helps, but you can get the same results with a ruler and protractor.
- Antenna Ads in ARRL Publications (55,578 bytes, PDF file)
QST April 1998, pp. 54-56
After more than 35 years, antenna manufacturers may once again advertise performance figures in League publications. Why has this changed and what should the astute amateur consumer be looking for in an antenna ad (or product brochure)?
- An Examination of the Gamma Match (904,644 bytes, PDF file)
QST April 1969, pp. 11-15, 57
An in-depth theoretical discussion of the gamma match.
- Far-Field Fallacy
QEX December 1987, pp. 10-11
Put simply, the performance of a DX antenna needs to be measured under DX conditions.
- Why We Stack ‘Em! Covering All the Angles (1,933,115
bytes, PDF file)
A Presentation to The Yankee Clipper Contest
Club, Feb. 1, 2003,
Milford, CT, by Dean Straw, N6BV, Senior Assistant
Technical Editor, ARRL
Note:
Contact information for suppliers mentioned in the above articles should first be confirmed using TIS Address Database Search.
Bibliography (Members Only)
ARRL Periodicals Index Search - This database contains the QST index from 1915 to the present and the QEX index from 1981 to the present. For QST issues from 1970 to the present, and some selected articles back to 1922 (when construction articles featuring tubes began in earnest), identifying keywords have been added to the technical articles. By entering keywords (ANTENNA) or combinations of keywords (CONSTRUCTION ANTENNA VERTICAL HF) into the Title words: field, you may create dynamic bibliographies.
Technical article KEYWORD list. Hints for more successful searching
Suggested keywords for more articles like the ones on this page are ANTENNA THEORY ANTENNA PRIMER ANTENNA TUTORIAL
Web Links:
Article Reprints:
You can get a photocopy of any ARRL published article for $3
($5 for nonmembers) for each article requested. Contact the ARRL Technical
Department (reprints@arrl.org ),
1-860-594-0390) if you wish to get photocopies.
This information was prepared as a membership service by the American Radio Relay League, Inc., Technical Information Service, 225 Main St., Newington, CT 06111 (860) 594-0214. Email: tis@arrl.org (Internet). ARRL HQ is glad to provide this information on the Web free of charge as a service to League members and affiliated clubs.
If you have any questions concerning the reproduction or distribution of this material, please contact:
TIS Coordinator
American Radio Relay League
225 Main St., Newington, CT 06111
Tel: 860-594-0214 Fax: 860-594-0259
(email: tis@arrl.org)
Page last modified: 12:16 PM, 23 Jul 2007 ET
Page author: tis@arrl.org
Copyright © 2007, American Radio Relay League, Inc. All Rights Reserved.
