MIL-STD-1605A(SH)
g. Alternative RF sensor measurement. When an RF sensor cannot be directly monitored, as in a hard wired sensor to equipment or integrated antenna that cannot be disconnected, the ambient level maybe monitored in the RF sensors location. The RF sensor system shall be shut down when performing this test, and all other below deck equipment must be energized. The test set up shall be configured to have the same sensitivity as the system under test. Using the calibrated antenna in the RF sensors frequency band, and polarization identical to RF sensors, place the antenna in close proximity (≤1 meter) from the sensor, and using the same analyzer outlined in 5.1.3.1.a, along with table I bandwidth and settings, measure the RF ambient over the sensors required bandwidth plus and minus
one bandwidth. If the test antennas directivity is less than the RF sensor antennas directivity then the test antenna shall be moved in increments of its beam width to cover the same beam width of the RF sensor antenna. Document the results in the test report noting antenna used, RF sensor location relative to antenna, and unintentional emissions evaluation criteria, 5.1.3.1.e. If unintentional emissions is detected, source location in accordance with 5.1.3.1.f shall be used to isolate the offending equipment/system causing excessive emissions.
5.1.4 Testing susceptibility of installed equipment/systems to portable RF transmitters.
a. Identification of non-operational equipment. Note the nomenclature/model of any equipment/system in the space that is not operational.
b. Transmitting RF. Key own ship portable radio(s) at its maximum operational power level, within 18-inches of the specific electrical/electronic equipment/system/sensor being evaluated, while the electrical/electronic equipment/system/sensor is in its normal operational condition. For large equipments, move the radio across the entire surface and rotate the radio to apply both horizontal and vertical polarities.
c. Identify results. If no susceptibility is noted return to 5.1.4.b until all electrical/electronic equipment/system/sensors have been tested in each space aboard the ship where the portable RF transmitter/transceiver will be utilized.
d. Action required. If susceptibility is identified, move the transceiver away from the victim equipment/ system/sensor until there is no susceptibility or reduce the transmitted power of the transceiver until there is no indication of susceptibility. Record the susceptibility indication and the distance/power level where susceptibility is eliminated. Return to 5.1.4.b until all electrical/electronic equipment/system have been tested.
5.2 Phase II tests. All topside and below deck transmitters and receivers shall be operated during Phase II testing to present the normal operational electromagnetic environment when the ship is at least 50nm from shore. Also, IMI testing shall be conducted on HF systems.
5.2.1 Phase II planning. Planning for system-to-system EMI testing shall begin well before the testing commences and shall include identifying the ship's topside antenna arrangement, ship's electronic system inventory, and the operating and intermediate frequencies of all installed RF transmitter and receiver systems. Verify prior to Phase II testing that the systems to be tested meet minimum operational specifications. If the system does not meet its operational specifications then the test director shall document in his report that system was not available for test and that Phase II testing could not be completed as required. Testing shall not be reported as completed until all systems are tested.
a. Transmitter frequencies. Well in advance of conducting the test, sufficient frequencies to cover all communication transmitter frequencies, in approximately 10 percent steps, for Phase II testing shall be requested from the area frequency coordinator. Transmitter test frequencies for HF IMI testing shall be used for system-to- system testing. Radar, Tactical Air Navigation (TACAN), and weapons systems shall be operated on their normal frequencies, while multi-channel system transmitters shall be operated at frequencies that are selected neither to minimize nor to intensify interference to other systems. If a change in transmit frequency changes the interference situation, this condition shall be noted. Two HF receivers and at least one UHF receiver, respectively, shall be selected to monitor HF and UHF ranges during transmitter tests to include harmonics of selected frequencies.
b. Radar receivers. Radar receivers shall be operated with normal gain control, video selection, processing mode, and receiver bandwidth settings. While most radars have digital video signal processing, the raw video signal of the radar shall be monitored while radiating HF, VHF, and UHF at the IF frequency of the radar receiver.
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