SCTE 48-3 2021

Test Procedure for Measuring Shielding Effectiveness of Coaxial Cable and Connectors Using the GTEM Cell

Executive Summary

The shielding attributes of components in a CATV system are critical to system performance. Ingress and egress issues can have detrimental effects on the overall performance of the system from both regulatory and quality perspectives.

Ingress issues can cause problems with television picture quality, and the effective transfer of data by allowing interfering signals into the system.

Egress issues can allow signals captured in the system to leak out and possibly interfere with wireless communications which utilize the same frequencies as those signals being leaked from the system.

It is the goal of this document to address the coaxial cables and connectors in the system, and how to properly gauge their performance in this critical area.

Scope

This document details the procedure for measuring the Ssielding effectiveness (SE) of coaxial cable and connectors using the gigahertz transverse electromagnetic (GTEM) cell. More particularly, this procedure applies to measuring the S.E. of 75 ohm braided coaxial drop cables and connectors presently used within the broadband communications industry. S.E. measurements can be performed with or without the affixing coaxial connectors removed from the measurement.

Benefits

This procedure exists in order to provide a standard method of testing between laboratories performing shielding effectiveness tests. When utilized this procedure helps to ensure confidence in results when published.

Areas for Further Investigation or to be Added in Future Versions

Future revisions of this document may build upon the work started here by increasing the understanding of:

  •  Variability of data between GTEM Cell systems with varied “uniform field” sizes.
  •  The affects of location differences between bare wire and shielded samples within the GTEM cell.