MIL-STD-469 Radar Engineering Interface Requirements, Electromagnetic Compatibility See Notice 1 For Replacement InformationThis standard establishes the engineering interface requirements to control the electromagnetic emission and susceptibility characteristics of all new military radar equipment and systems operating between 100 megahertz MHz, and 100 gigahertz GHz, to ensure EMC in all intended operational environments, and to conserve the frequency spectrum available to military radar systems.

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MIL-STD-469B APPENDIX A

PD      = PR

20 log (  )     GR + 11.0

where: PD

= power density at test antenna, dBm/m 2

PR       = radar Fo  level at test antenna terminals, dBm

GR      = test antenna gain, dB, and     = 300/fMHz, meters.

The power density at the test antenna should be compared to the expected F  o  power density level. The measured power density (equation on previous page) should agree within 2 dB of the expected power density (equation below). The equation for the main beam power density is:

PD      = PT  + GT

20 log R     11.0

where: PD PT GT

= power density at test antenna, dBm/m 2

= radar peak transmitted power, dBm

= radar antenna nomin al main beam gain, dB

R              = distance from radar antenna to test antenna, meters.

50.2.4.3  With all instrumentation set as specified, rotate the system antenna and start the recorder. The recorder should be operated to obtain two complete 360 degree sweeps of the system antenna on the recording. The recorder response times and antenna rotational speeds necessary to give at least 1 dB accuracy in the antenna pattern recording should be obtained from the following

equation:

W < 50

3dB/Tr

where:

W      = rotational speed, r/min

3dB

Tr

= 3  dB width of antenna main lobe, degrees

= response time of the test receive r and instrumentation, milliseconds.

50.2.4.4  To calibrate the antenna pattern recording, the main beam of the radar antenna should be

re-aligned for a maximum received level on the test antenna. Additional attenuation should be inserted in the line from the test antenna, in 5 dB steps. After each 5 dB increase, the resulting deflection of the recorder pen should be marked.

50.2.4.5  For antennas that can be elevated, an antenna pattern measurement should be performed in the vertical plane using the procedure described for the azimuthal pattern recording.

50.2.4.6  For electronic beam-scanning antenna which cannot be mechanically rotated, the following procedures should be used. The test antenna should be placed sequentially at 10 equally spaced angular positions, with the test antenna positioned as high as possible but not above the lowest elevation of the system antenna main beam maximum for the following tests. The test antenna  positions should be on a semi-circular arc starting at the azimuth boresight location and ending 180 degrees offset in azimuth. One each of the test positions should be at each end of the specified arc.  (Phased array systems are usually symmetrical by design; the mirror image of the test positions with  associated data should be reflected to the other side of the

antenna.)

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