RTCA/DO-160 Section 21: Emission Of Radio Frequency Energy
The tests in RTCA/DO-160 Section 21 are performed to ensure that the Equipment Under Test (EUT) does not emit Radio Frequency interferences that exceed the specified limits. Conducted RF emissions exposed to interconnecting cables and power leads are measured. Radiated RF emissions from the EUT, power leads, and interconnecting cables are also measured.
Measurements must be made with an instrument using a peak detector, and with IF bandwidths, frequency step size, and dwell time as specified in RTCA/DO-160 Section 21, Table 1, for the frequency range being scanned.
A-Line Impedance Stabilization Network (LISN) must be placed in series with each power lead and ungrounded power return lead, with a 10 uF capacitor connected between the power input of the LISN and the ground plane.
Interconnecting cables should be at least 3.3 meters in length, and power leads will be no more than 1 meter in length for these tests unless otherwise specified.
Ambient emission levels must be at least 6 dB below the applicable limit and must be measured and recorded if any signals are found to be within 3 dB of the applicable limit.