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DO-160-Section-20-RF-Susceptibility

RTCA DO-160 Section 20.0 Radio Frequency Susceptibility (Radiated and Conducted)

The RTCA DO-160 radiated susceptibility test standard determines whether equipment will operate in required performance specifications. The equipment is evaluated when it and its interconnecting wiring are exposed to a level of RF modulated power. The RF is introduced by a radiated RF field or by injection probe induction onto the power lines and interface circuit wiring.

RTCA/DO-160G testing has two procedures. The first susceptibility test is a conducted susceptibility test. The frequency range is from 10kHz to 400 MHz. The equipment to be tested is exposed to RF signals coupled by means of injection probes into the cable bundles. The second susceptibility test is radiated susceptibility. This test, spelled out in RTCA/DO-160G, is for frequencies between 400 MHz and the upper limit. The equipment to be tested is exposed to radiated RF fields. The RTCA-DO-160G testing standard does have an intentional overlap from 100 MHz to 400 MHz.

The RTCA DO-160 test lab can conduct the radiated susceptibility tests from100 MHz to 18 GHz one of two ways. One way is by using a reverberation chamber method. The second way is by using the anechoic chamber method. The customer can select the method they want the radiated susceptibility test lab to use.

The RTCA-DO-160G Section 20 testing standard categorizes equipment. The categories designate the RF test levels and the RF immunity level. The category itself must be identified before the internal RF of the aircraft is known. This can create uncertainty. For this reason, the manufacturer should design, qualify and test the equipment to the category consistent with the expected exposure, location and use of the equipment.

The designation of the equipment category is based on two variables. Conducted susceptibility test levels are designated with the first category character. Radiated susceptibility test levels are designated with the second category character. The equipment location, anticipated exposure/location of interconnecting wiring, and aircraft size and construction will always determine the test level.

The following section outlines the equipment categories spelled out in RTCA DO 160G testing:

  • Categories B, D, F, G, L, M and O provide test levels which directly relate to the high intensity radiated field (HIRF) external field environments for systems with highest criticality as specified in the HIRF regulations.
  • Category R provides test levels for equipment under certain circumstances.
    • Bench testing is allowed to meet the HIRF for systems with high criticality as specified in the HIRF regulations. And
    • Showing backdoor Transmitting-Portable Electronic Device (T-PED) tolerance.
  • Category S provides a minimum test level where aircraft effects from the external electromagnetic environment are minor and where interference free operation on the aircraft is desirable but not required. This category may also be representative of the internal EMI environment from aircraft equipment.
  • Category T provides test levels for equipment when bench testing is allowed to meet the HIRF for systems with moderate criticality as specified in the HIRF regulations. This category may also be representative of the internal EMI environment from aircraft equipment.
  • Categories W and Y provide test levels for two criteria.
    • Bench testing supporting compliance to HIRF Special Conditions, and
    • Showing backdoor T-PED tolerance
  • Category Q indicates tests conducted at test limits or with modulations other than those specified in these procedures.

Keystone Compliance is one of the leading radiated and conducted susceptibility EMC test labs in the country. With seven EMC test chambers a substantial amount of test equipment, we are able to offer shot lead times on scheduling. Our engineers provide communication throughout the entire test program. If challenges arise during the testing, our engineers will provide engineering guidance and problem resolution. Our radiated susceptibility lab is 17025 accredited to RTCADO-160 testing. In addition to providing RTCA-DO-160G testing, Keystone is accredited to all previous versions of this military test standard as well.

Our EMC-EMI test lab can accommodate small and large items. Please contact us to see firsthand why so many manufacturers rely on Keystone Compliance to be their RTCA DO-160 test lab.

Looking for other testing to other sections of RTCA DO-160 testing? Click on the links below:

Modifications from one Version of RTCA DO-160 to the Next:

Changes from DO-160C RF Susceptibility Testing to DO-160D RF Susceptibility Testing

The revisions to Section 20, in DO-160D Change No.1, published December 2000, include a new, Mode-Tuned, Reverberation Chamber Radiated RF Susceptibility test method. New categories (test levels) were also added to Section 20, including Category L, which requires Radiated RF Susceptibility testing (pulsed) as high as 7200 volts/meter. An alternate procedure was added for mode-stirred radiated susceptibility tests. The mode-stirred procedure was accepted as an alternate that may require lower-power amplifiers.

Changes from DO-160D RF Susceptibility Testing to DO-160E RF Susceptibility Testing

A section providing guidance and caution related to RF power amplifier harmonics and their potential to affect the test results was added, along with a revision that allows the use of an oscilloscope to measure Conducted Susceptibility test levels. The Mode-Tuned test method for Radiated Susceptibility was modified to allow for the option of using the received power on the monitor antenna to determine the test level, as opposed the E-field readings from a 3-axis sensor. Flexibility in the number of tuner steps was also added, giving the user the choice of increasing the number of steps based on the need for greater field uniformity or a higher test level, or decreasing the number of tuner steps to decrease the test time.

Changes from DO-160E RF Susceptibility Testing to DO-160F RF Susceptibility Testing

Test categories were reduced and “alternative” modulations for Category R were eliminated. There is now only one test method for conducted susceptibility.  Clarification has been added regarding the requirement to expose all apertures and openings of the EUT in anechoic chamber method.  RTCA/DO-160F added requirements to test several additional dwell frequencies where the image frequencies for n =2 through 10.  160F removed the permissive language associated with these tests. It used to be “should” but 160F now uses “shall”.

Changes from DO-160F RF Susceptibility Testing to DO-160G RF Susceptibility Testing

Indicated that section categories are appropriate for Transmitting Portable Electronic Device. Clarified that power lines may, but are not required to, be routed with interconnect wiring, unless this conflicts with aircraft installation specifications.  Indicated that the radiating antenna may be placed further than 1 meter from EUT. Significant change to reverberation chamber testing made by replacing “Mode Tuning” test technique with “Mode Stirring” technique.