Investigation of low frequency emissions due to interfacing cables in RE 102

In this paper, it has been shown through measurements that violation of Radiated Emission (RE) threshold limit of MIL-STD-461F due to various kinds of cable connecting the Equipment Under Test (EUT) (inside the chamber) and test & monitoring equipment (outside the chamber) including the power source, occurs in a certain frequency range, the value of which depends on the length of the interfacing cables regardless of the unit being tested. It has further been demonstrated that when the power to EUT is supplied by placing batteries inside the chamber (as would be the case in actual system), the peculiar RE violations of MIL-STD-461F RE limits disappears, no matter which unit is being tested. This clearly indicates that the RE violations in this particular band are due to the cables connecting the power source with EUT. It is therefor proposed that if the batteries of adequate power are available, the system should be operated and tested for RE 102 compliance, by placing the batteries inside the chamber.