Assessing the effects of an OATS shelter: is ANSI C63.7 enough?

This paper summarizes a previous measurement effort by NIST researchers at an open-area test site (OATS), operated by a large information technology equipment manufacturer. The purpose of this effort was to assess the effects on emissions measurements of a fiberglass dielectric shelter that is used to protect and temperature stabilize information technology equipment undergoing emissions tests. NIST researchers and industry are seeking to answer questions about the impact of OATS shelters using an ultra wideband time-domain measurement system. This paper summarizes the instrumentation used, the measurement methodologies, and the data obtained. The results indicate that the fiberglass shelter can have a significant impact at frequencies above 100 MHz, a result which should be of interest to the emissions testing community.