DEPARTMENT OF DEFENSE INTERFACE STANDARD

MIL-STD 461 RE103 Radiated Emissions, Antenna Spurious and Harmonic Outputs

This test procedure is used to verify that radiated spurious and harmonic emissions from transmitters do not exceed the specified requirements.

Applicability

This requirement may be used as an alternative for CE106 when testing transmitters with their intended antennas. This requirement is met if the emissions do not exceed the applicable RE102 limit in transmit mode. CE106 is the preferred requirement unless the equipment or subsystem design characteristics preclude its use. RE103 should be the preferred method for systems using active antenna or when the antenna impedance has a non-standard impedance curve. The requirement is applicable from 10 kHz to 40 GHz and not applicable within the bandwidth of the EUT transmitted signal or within ±5 percent of the fundamental frequency, whichever is larger. For Navy shipboard applications with peak transmitter power (PtPk) greater than 1 kW, the 5% frequency exclusion is increased by an additional 0.1% of the fundamental frequency for each dB above 1 kW of peak power.

Frequency Exclusion = ±f * (0.05 + (0.001/dB) * (PtPk [dBm] - 60 [dBm]))

Depending on the operating frequency range of the EUT, the start frequency of the test is as follows:



Operating Frequency Range (EUT)
Start Frequency of Test


10 kHz to 3 MHz
10 kHz


3 MHz to 300 MHz
3 MHz


300 MHz to 3 GHz
1 MHz


3 GHz to 40 GHz
10 MHz



The equipment will be tested to an upper frequency limit based on the highest frequency generated or received by the EUT. For systems with the frequencies generated or received less than 1 GHz, the upper frequency limit will be 20 times the highest frequency or 18 GHz whichever is greater. For systems with frequencies generated or received greater than or equal to 1 GHz, the upper frequency limit will be 10 times the highest frequency or 40 GHz whichever is less. For equipment using waveguide, the requirement does not apply below eight-tenths of the waveguide's cutoff frequency.

Limits

Harmonics, except the second and third, and all other spurious emissions shall be at least 80 dB down from the level at the fundamental. The second and third harmonics shall be suppressed to a level of -20 dBm or 80 dB below the fundamental, whichever requires less suppression. For Navy shipboard applications, the second and third harmonics will be suppressed to a level of -20 dBm and all other harmonics and spurious emissions shall be suppressed to -40 dBm, except if the duty cycle of the emissions are less than 0.2%, then the limit may be relaxed to 0 dBm.

Test Equipment

 	
Measurement receiver
 	
Attenuators, 50 ohm
 	
Antennas
 	
Rejection networks
 	
Signal generators
 	
Power monitor

Preview Standard