RadiMation Application Note 147

How to perform a MIL-STD RE101 Radiated Emission test

This application note explains how the MIL-STD RE101 Radiated Emission test can be performed with RadiMation^®.

The "RE101, radiated emissions, magnetic field" test is applicable to equipment, subsystem enclosures and all interconnecting cables and is used to verify that the magnetic field emissions from the EUT and cabling do not exceed the specified requirements.

The exact requirements and test methods for the RE101 are specified in the MIL-STD-461.

Necessary equipment

The following devices are necessary to execute this test:

• Receiver
• Loop sensor (Antenna)
• LISN
• Cable

Configuration of the testsites

The configuration of the equipment is a loop sensor antenna connected with a cable to a receiver.

The configuration of the testsite should thus contain the following devices:

Device name	Tab in testsite configuration window	note
Antenna	Devices 1	Loop sensor antenna for the required frequency range
Spectrum Analyser	Devices 2	The receiver used for the test
Cable preamp -> analyser	Cables	Cable with a correction file specified for the loss

Note the lisn is only used to decouple and it is not needed to specify and configure this in RadiMation^®

Configuration of the Loop sensor antenna

The loop antenna needs to have the correction data applied which is normally known by the manufacturer. The correction data is expressed in dBpT.

In RadiMation^® this can be configured by creating a correction file, which contains a 'Frequency' and a 'Correction' column. Then specify the frequencies and the correction values in the correction file. The correction values are expressed in dBpT/uV.

Once this correction is stored to disk, this correction file can be specified in the loop antenna driver configuration as 'Magnetic Field Factor':

Perform the test

To perform the actual RE101 test, start a Radiated Emission Multiband test:

    Tests

       Radiated Emission

          Multiband

The complete test from 30 Hz up to 150 kHz has different settings for different frequency bands. All these different bands can be configured. The test can be configured with 3 bands, each using their applicable frequency range, measure time and bandwidth.

Band	Frequency range	RBW	Step size	Measure time receiver	Measure time FFT receiver
Band 1	30 Hz - 1 kHz	10 Hz	5 Hz	0.15 s	1 s
Band 2	1 kHz - 10 kHz	100 Hz	50 Hz	0.015 s	1 s
Band 3	10 kHz - 150 kHz	1 kHz	500 Hz	0.015 s	1 s

In the following test configuration an EUT for Navy Application is tested.

Start

The start frequency of the test. For example 30 kHz.

Stop	The stop frequency of the test. For example 100 kHz.

Reference Level

The reference level set in an analyser, not used in a receiver

Attenuation

The attenuation set in the receiver

RBW	The RBW set in the receiver, see table with different bands for possible values

Step size

The step size set in the receiver, see table with different bands for possible values

Measure time

The measure time set in the receiver, see table with different bands for possible values

Preamplifier

The preamplifier setting set in the receiver

Traces

The type of trace set in the receiver, for MIL-STD RE101 a peak detector is used

Test Equipment

The equipment used for the measurement, see table with different bands for possible values

Location type

Set this to "Antenna height, distance, polararization and angle"

Max Height

The maximum height for the antenna tower, configuration is depending on how many positions should be measured

Min Height

The minimal height for the antenna tower, configuration is depending on how many positions should be measured

Steps

The number of height positions to measure, configuration is depending on how many positions should be measured

Move during measurement

If the antenna tower can move during the measurement, not used during MIL-STD RE101 measurement

Optimize Height

Find the optimal emission around a certain height, not used during MIL-STD RE101 measurement

Distance

The used antenna distance, 7cm for MIL-STD RE101

Antenna Polarization

Which polarization is used, Vertical, Horizontal or Both, above 30 MHz both polarization should be tested

Start Angle

The minimal turn table angle

End Angle

The maximum turn table angle

Steps

The number of angles to measure

Turn during measurement

If the turn table can move during the measurement, not applicable for MIL-STD RE101

Optimize Angle

Find the optimal emission around a certain angle, not applicable for MIL-STD RE101

EUT Angle Offset

The offset of the EUT on the table, not applicable for MIL-STD RE101

Limit Lines

The applicable limit line can be added, in this case "MIL-STD-461G RE101-2 Navy Applications"

All peaks above x dB below the limit line

Which level above x dB below the limit line should detect peaks, no peaks should be measured in MIL-STD RE101

Peak detection

How many peaks should be detected automatically, no peaks should be measured for MIL-STD RE101

Final peak measurement

It is possible to perform a final measurement on a peak with a specific detector, no final peak measurement is needed for RE101

When all parameters are configured for the RE101 test, press Start Test to perform the emission measurement.

Review the initial scan and measure frequencies of maximum emission

With the the frequencies of maximum emission located, add the frequencies as peaks by clicking in the graph. A list of frequencies should appear below in the peaks tab.

To measure a single frequency:

1. Select one frequency by checking one single frequency.
2. Click Peak Actions and select Set receiver to Peak settings to set the correct measure time and RBW as configured.
3. Enable Continuous Measure and move the loop antenna to find the maximum radiation.
4. Click Continuous Measure again to stop the measurement.
5. repeat this step for each frequency.