I was pleased to see that my article (written along with Nils Nazoa), "Evaluate Accuracy Of Portable VNAs," was published in the January 2007 issue of Microwaves & RF (p. 58) as planned. However, there are three points that I would like to bring to your attention regarding the article as published:

  1. The sidebar section, describing calculating return loss uncertainty and uncertainty in phase, is missing from the article. This is most unfortunate as equations (3, 4, and 5) in this section are referred to in the main text of the article so the article, as printed, is incomplete.
  2. Throughout the article, the customary capital gamma symbol used to represent voltage reflection coefficient has been changed into an asterisk (*) symbol. This may cause some confusion to readers of the article.
  3. The subheading to the article reads, "The first portion of this two-part article . . . ." We were not planning a second part, so this is not correct

Apart from the above three points, I think the article looks really good.
Nick M. Ridler
Principal Research Scientist
Electromagnetics Team National Physical Laboratory
Teddington, Middlesex, UK

Editor's Note: We mistakenly referred to your article as "the first portion" because we had originally envisioned it as a two-part series. Another article dropped out of the issue, so we had room to run your article in its entirety.

The sidebar that you mentioned in your letter does appear on the Microwaves & RF website. It was cut from the print issue due to lack of space. Readers can find the sidebar, titled "Calculating Return-Loss Uncertainty," online at: http://www.mwrf.com/Articles/ArticleID/14641/14641.html