MIL-STD-469B APPENDIX A
30.13 For transmitter testing a sampling device should be used, where needed, to measure the output level of each signal component emitted. The coupling factor of the device should be known within 1 dB at each measurement frequency. The requirement for sampling device calibration should be waived if the device coupling loss is included when signal levels are substituted for calibration levels.
30.14 Power meters used for measuring the sampled output from transmitters, measuring reference outputs from signal generators, or other power measurements, should have a full scale accuracy within 5 percent of the indicated power.
30.15 Radar operation.
30.15.1 Condition for measurements. The equipment to be measured should be set up so that it closely approximates the normal operating conditions. The steps specified in the operation and maintenance portions of the radar technical manual should be performed prior to the measurements. The equipment should be aligned in accordance with the pertinent instructions, such that it is represented under normal operating conditions, not deliberately optimized at specific operating frequencies used in the measurements.
30.15.2 Radar tuned frequencies. Measurements should be made with the radar tuned to each of the frequencies as specified in table III for the appropriate radar category. If the radar operates over more than one frequency band, that is, multiple bands, the criteria for selecting radar tuned frequencies should be applied to each band.
30.16 Test sites.
30.16.1 Selection criteria. In the receiver measurements for both coaxial and waveguide systems, the test site should normally be in the vicinity of the radar system. This location provides for convenient injection of
test signals and extraction of signal outputs during the measurement of receiver parameters. The transmitter requirements refer to the radar antenna terminals. Therefore, the measurement of transmitter signals should be made as close as practical to the antenna terminals. The transmitter output test points should be selected as the plane of reference for transmitter measurements in the following order of preference:
a. Closed system with system signal sampler at the antenna input
b. Closed system with test signal sampler inserted at the antenna input
c. Closed system with radar signal sampler or test signal sampler located at or beyond the transmitter output and before the radar antenna input
d. Open-field reception of the radiated radar emission with a calibrated test antenna.
A near field antenna test range may be used in lieu of an open field test site for phased array antennas. The upper end of the test frequency range for closed system transmitter measurements will be limited by the characteristics of the device used to sample the radar output signal and by the characteristics of the transmission line between the sampling device and the radar antenna feed. Open field measurements should be used for determining transmitter characteristics beyond the upper end of the range for closed system measurements. Antenna characteristics should be measured from an open field test site. An anechoic chamber may be used in lieu of an open field test site, providing the chamber will approximate free space conditions over the range of measurement frequencies.
30.16.2 Closed system test sites. Receiver tests should be made closed system. Transmitters using coaxial systems should be made closed system up to the frequency where the device for sampling the radar signal
cannot provide a reliable correlation of the measured data to radar antenna input levels. Transmitters using
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