The classic SEAD/DEAD weapon is the anti-radiation missile (ARM), such as the American AGM-88 HARM (High-speed Anti-Radiation Missile). At its core this is passive homing (Missile Guidance): the missile seeks out the radar emission itself and flies to its source — it needs no transmitter of its own and so does not give itself away.
This creates the notorious operator's dilemma for the radar crew:
- Do I keep transmitting? Then I can see and engage the strike package — but the ARM follows my emissions straight to me.
- Do I switch the radar off? Then the ARM loses its lock on me — but I am now blind and cannot hit anything myself.
The attacker tries to make this dilemma inescapable; the defender tries to escape it. That is why modern ARMs have a home-on-jam and a memory mode: switch the radar off and the missile remembers the last known position and flies there anyway. The radar operator therefore gains little by simply switching off.
Defenders respond with “shoot-and-scoot”: transmit briefly, fire, and move immediately before the ARM arrives. Mobility and short emission times (see also EMCON, Doctrine & EMSO) are thus a direct countermeasure against DEAD — a neat illustration of the cat-and-mouse game between EA and EP (Electronic Counter Measures–12).