In SEW operations, which statement best distinguishes active defense measures from passive defense measures?

• A. Passive measures involve actively jamming the adversary's emissions to degrade their capabilities.
• B. Active measures attempt to degrade or defeat the threat (jamming, anti-jamming, signal generation to mislead) while passive measures aim to avoid detection or minimize impact (spectrum management, shielding, concealment, redundancy).
• C. Passive measures involve using high-power broad-spectrum emissions to disrupt adversaries.
• D. Active measures rely solely on physical attacks and have no spectrum-domain effects.

Answer: (B)

In SEW operations, the distinction hinges on whether the action engages the spectrum to counter the threat or focuses on reducing vulnerability without actively opposing it. Active defense measures are actions that interfere with or deceive the adversary in the spectrum domain—jamming emissions, anti-jamming techniques, and generating signals to mislead. Passive defense measures, on the other hand, aim to avoid detection or minimize impact—through spectrum management to reduce interference, shielding to hide from sensing, concealment, and redundancy to survive or withstand attacks. The statement in question captures this split correctly by describing active measures as those that degrade or defeat the threat and passive measures as those that avoid detection or minimize impact. Jamming and signal manipulation are quintessential active actions, so assigning them to passive would be inaccurate. Similarly, using high-power broad-spectrum emissions to disrupt is an active approach, not passive, and active defenses are not limited to physical attacks without spectrum effects.