"This guide provides information on construction of radiated emission test facilities in the frequency range of 30 MHz to 40 GHz. Standardized site validation methods above 18 GHz remain unavailable at present@ however the changes in this edition are considered appropriate guidance for use up to 40 GHz. In general@ the construction techniques described apply either below 1 GHz@ or for 1 GHz and above. This guide does not address construction code compliance issues. Parties responsible for the design and construction of test sites are advised to consult with the various authorities having jurisdiction (AHJ) to determine the building@ HVAC@ plumbing@ electrical@ etc.@ codes and regulations that are applicable for the test site. In addition@ beyond the similarity of basic principles@ this guide also does not specifically address considerations on construction of test sites used for calibration of antennas used in EMC radiated emissions measurements; that topic is covered in ANSI C63.5.1@2 In addition@ site-dependent measurement instrumentation and signal cabling issues are not in the scope of this guide. Purpose To account for the frequency ranges and differing measurement needs as described in 1.1@ this document provides construction guidance focused on two applications: a) At 1 GHz and below@ the test site can be either an open-area test site (OATS) or a semi-anechoic chamber (SAC). b) At 1 GHz and above@ the test site can be an OATS with absorber material on a portion of the ground plane@ a SAC with absorber on a portion of the ground plane@ or a SAC with absorbers on all conductive surfaces; the latter test site is called a fully anechoic room (FAR).3 Common construction techniques are also described that apply for all the above test facilities. NOTE??As a guide@ this document does not contain requirements or specifications because the material is meant to be informative. However@ some of the guidance should be strongly considered because not taking the guidance can lead to a test site that does not meet site validation requirements which are specified in such documents as ANSI C63.4. On the other hand@ some of the guidance identifies what to consider among several options. As this guide is read@ keep in mind that there are these levels of consideration. The sense of these levels of consideration as indicated by the verbs used is given in the following list. A search of the document will show where ""should@"" ""recommended@"" and ""might"" appear@ the criteria below will give the emphasis needed. Also@ different from the usual style for IEEE standards of marking annexes as normative or informative@ because all annexes in this document are informative thus such marking is unneeded. -""Strongly suggested"" is identified by use of the verb ""should."" -Items ""to be considered"" are identified by the use of the verb ""recommended"" or ""might."" -""Is possible"" is identified by use of the verb ""can."" -There is no use of the normative verbs such as ""shall"" and ""must"" in this guide. 1 For information on references@ see Clause 2. 2 ANSI C63? publications are available from The Institute of Electrical and Electronics Engineers (http://standards.ieee.org/) or from the American National Standards Institute (http://www.ansi.org/). 3 Various other international and national standards and open literature have used the acronym FAR to refer to fully absorber-lined environments@ i.e.@ shielded or unshielded chambers or rooms having absorber material covering all internal surfaces in their entirety. For the purposes of this document@ FAR is used to refer to a performance-based fully anechoic condition with reflections reduced to below specified levels; see 5.4."