Although specifically dealing with aircraft systems, the methods described in this article are applicable for other platforms where a number of antennas are in close proximity. The number of antennas in use and in close proximity on mission specific aircraft are as many as 22 on a small search and rescue aircraft. ANALYSIS METHODS The methods of coupling analysis include … [Read more...]
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Protecting RF, Receiver, Analog and Control Line Input Circuits Against The RTCA DO-160 Pin Injection Lightning Test
ABSTRACT Circuits are described that effectively protect RF, receiver, analog, and control line input circuits from three types of transient injection, described in DO-160, directly into the input pin of the connector. The goal was to achieve a circuit which would not adversely affect the performance of the RF circuit over an input frequency range of 20MHz to above 1GHz … [Read more...]
Placing a Metal Plate in Front of a EUT May Not Be Enough to Solve Radiated Emissions Exceedances or Radiated Susceptibility Failures
EXAMPLE OF AN EUT WHICH HAS FAILED RADIATED SUSCEPTIBILITY As described in reference 1, the EUT was exposed to a radiated immunity test at a level of 20V/m. The side which contained a vertical metal plate, with an approximately 0.3m x 0.3m dimension and which was electrically isolated from a metal baseplate failed at 12V/m and 300MHz. On the other sides of the EUT, … [Read more...]
An Isotropic Probe for Radiated Susceptibility Measurements from 10kHz to 18GHz and 5V/m to 220V/m
Abstract: Isotropic probes are available for radiated susceptibility test level measurements from 100kHz to 6GHz, 2MHz to 18GHz, 2MHz to 40GHz and 2MHz to 60GHz. For MIL-STD-461 and DO-160 testing a frequency range of 10kHz to 18GHz would be better and a possible solution is presented here. Introduction The probe described in this paper has three separate sections, … [Read more...]
Effectiveness of a Triaxial Cable Using Pigtails to Terminate the Outer Shield to Chassis Versus a Coaxial Cable With the Shield
Introduction Although it should be well known that the shielding effectiveness of a cable is severely compromised when it is terminated to ground with pigtail/s many equipment manufacturers still use this technique. We see in Reference 1 Figure 7.66 and Table 7.4, Figure 7.80, and Figure 7.102 that the shielding effectiveness of a coaxial cable with pigtail terminations may … [Read more...]
Circuit Level Design and Test for the MIL-STD-461 200 V/m RS103 and the DO-160 Radiated Susceptibility Test at 200 V/m
Introduction For Army, Navy, and Air Force military equipment and DO-160 commercial aircraft avionics, radiated susceptibility test levels as high as 200 V/m may be specified. As always, it is better to design immunity to the test levels into equipment than to wait until equipment is completed and then perform tests. This article assumes the worst-case qualification test … [Read more...]
Determining Semi-Anechoic Chamber Resonance as a Source of Radiated Emission Measurement Variation Between Chambers and Comparing to OATS Measurements
INTRODUCTION This article describes the lack of an acceptable correlation between anechoic chamber and open field test site radiated emission measurements, which were described in reference 1 in 2000, as well as a lack of correlation between chambers. It was found that emission measurements, which were over the limits in one facility, would pass in another. The lack of a … [Read more...]
