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Understanding transmission lines is an important part of the art of radio--the proper selection and use of a feedline is often more important than the choice of radio. This is particularly true of multiband antennas fed with tuners--it is possible to lose several S-units of transmit signal strength by making poor decisions.

Additional information on this subject and related topics can be found in back issues of QST and the following:

The ARRL Antenna Book
Transmission Line Transformers

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.

• Understanding SWR by Example (180 kb, PDF file)
  QST November 2006
• Measuring Cable Loss (342,971 bytes, PDF file)
  QEX May/June 2005
• Better Feedline Loss Measurements with Antenna Analyzers (123,881 bytes, PDF file)
  QST March 2004 Hints and Kinks
• Measuring Cable Loss (343,061 bytes, PDF file)
  QEX, May 2005, pp 44-46
  An improved-accuracy method of measuring coaxial cable loss with antenna analyzers.
• Using 1/2-Inch 75-Ohm CATV Hardline (48,839 bytes, PDF file)
  QST January 2000, p. 91 (World Above 50 MHz)
  Consider using Hardline when planning a VHF/UHF repeater or even a home station.
• Don't Solder to Connector Adapters!
  QST December 1995, p.76 (Hints and Hinks)
  A warning about the installation of PL-259s to smaller coax cable.
• "My Feed Line Tunes My Antenna!" (282,589 bytes, PDF file)
  QST November 1991, pp. 33-35
  A discussion on how the feed line can change the resonant frequency of the antenna.
• The Whys of Transmission Lines Part 1 (342,192 bytes, PDF file)
  QST January 1965, pp. 25-28
  A beginner’s guide to transmission lines.
  
• The Whys of Transmission Lines Part 2 (217,959 bytes, PDF file)
  QST February 1965, pp. 24-26
  Standing-wave ratio and line losses
  
• The Whys of Transmission Lines Part 3 (281,058 bytes, PDF file)
  QST March 1965, pp. 19-22
  Putting the antenna and line together
  
• Another Look at Reflections (1,114,112 bytes, PDF file)
  Everything you wanted to know about SWR … and then some.
  
• The SWR Obsession (458,752 bytes, PDF file)
  QST, April 1994, pp. 70-72, 74
  What is your SWR meter really saying?
  
• The Lure of the Ladder Line (883,079 bytes, PDF file)
  QST December 1993, pp. 70-71
  Discussion of some advantages to using ladder-line in place of coax to feed multiband dipoles.
  
• Proving the Conjugate Matching Power Theorem
  QEX July 2000, pp. 55-58
  
• Let's Talk Transmission Lines (37,970 bytes, PDF file)
  QST June 1997, pp. 57-59
  Coax or ladder-line? Which dielectric? How do I reduce losses?
• Opening Lines: A Short History of Coaxial Cable (80,232 bytes, PDF file)
  QST August 2001, pp. 62-64
  Nothing technical, just why coax is.

For information on a different but related subject, see Transmatch/Antenna Tuner

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: SWR

Web Links

• Bill Beech, NJ7P Coaxial Cable Searchable Database compiled by Paul Veltman, WA6OKQ. 

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 ), or  1-860-594-0390, between Noon and 5PM, Tuesday through Friday, 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)