FARS - Articles by Steve Stearns, K6OIK

"Conjugate Match Myths"

Presensation at ARRL Pacificon Antenna Seminar
October 14-16, 2011
Steve Stearns, K6OIK

ABSTRACT: Examines the effect of lossy transmission lines on SWR and the effects of mismatched loads on power transfer. This examination demonstrates that conjugate matching for maximum power transfer as described by Walter Maxwell is incorrect for lossy transmission lines.

You can download your own copy of this Conjugate Match Myths Lecture. You will need a PDF viewer to display this document. The document is 1.3MB.

"Facts about SWR and Loss"

Presensation at ARRL Pacificon Antenna Seminar
October 15, 2010
Steve Stearns, K6OIK

ABSTRACT: While much of conventional transmission line theory deals with lossless lines, such lines are but theoretical abstractions. Real transmission lines have loss, and some have high loss. Steve Stearns, K6OIK, covers the effect of loss on SWR and power transfer from a transmitter to an antenna. He explains the sometimes confusing graphs that have been published over the years and gives new ones that are more useful. He explains the difference between Zo matching and conjugate-impedance matching. He presents new results on maximum power transfer, which show that some popularly published ideas are not entirely correct. Finally, he shows how to maximize power transfer through a real, lossy line and explains the conditions when it should not be done.

You can download your own copy of this Facts about SWR and Loss Lecture. You will need a PDF viewer to display this document. The document is 1.7MB.

"Antenna Modeling for Radio Amateurs"

Presented at ARRL Pacificon Antenna Seminar
October 17, 2008
Steve Stearns, K6OIK

You can download your own copy of this Antenna Modeling for Radio Amateurs Lecture. You will need a PDF viewer to display this document. The document is 4.4MB.

"New Results on Antenna Impedance Models and Matching"

Presented at ARRL Pacificon Antenna Seminar
October 19, 2007
Steve Stearns, K6OIK

You can download your own copy of this New Results Lecture. You will need a PDF viewer to display this document. The document is 6.4MB.

"Antenna Impedance Models - Old and New"

Presented at ARRL Pacificon Antenna Seminar
October 15, 2004
Steve Stearns, K6OIK

You can download your own copy of this Antenna Impedance Models Lecture. You will need a PDF viewer to display this document. The document is 983KB, so it will take about 3 minutes to download with a 56K modem.

"Mysteries of the Smith Chart: Transmission Lines,
Impedance Matching, and Little Known Facts"

Presented at ARRL Pacificon '99, '01, and '02
Concord, California
Steve Stearns, K6OIK

ABSTRACT: This talk is divided into three parts: uniform transmission lines, the Smith chart, and matching networks. In Part 1 we review the historical development of uniform transmission lines. Topics covered are: line synthesis; the calculation of transmission line parameters from geometry, dimensions, and material properties; various "optimum" coax dimensions; impedance transformations, and the properties of special lengths of line, such as half-, quarter-, and eighth-wave lines. We show how to use an antenna analyzer to measure the characteristic impedance and velocity factor of a transmission line. In Part 2 we introduce the Smith chart and show that in addition to being an intuitive graphical method for solving complex impedance transformations, it can also be used as a nomogram for basic math calculations. In Part 3, we discuss the reasons for matching, the best ways to match, and the design of single-frequency, multiple-frequency, and broadband matching networks.

You can download your own copy of this (updated 2001) Smith Chart presentation. You will need a PDF viewer to display this document. The document is 2.3MB, so it will take about 10 minutes to download with a 56K modem.