ECM disrupts 'mech-scale tracking systems, to make it ~harder~ to hit a target; not impossible. It does squat to missiles in-flight. (think of ECM in the sense of making everyone within 180 metres of you get watery eyes because of a really bad smell, only your buddies are used to it, so it doesn't affect them; your enemies have a harder time 'seeing' but that doesn't stop whatever they shoot from flying straight.)<br/><br/>AMS can only reliably target missiles targeting ~your~ mech. What it effectively is, at its most basic level, is a thermal-guided .50 calibre flak gun that unloads hilarious amounts of ammo in short order. (1 ton of AMS ammo is 12 bursts, and it uses 1-6 bursts to knock down 2-12 missiles in a volley)<br/><br/>Almost every 'mech that does have an AMS only has 1 ton of ammo for it, so while you'll knock down 1-2 flights of missiles, or at least, trim it down to 'scratch' damage, It's more to mitigate the punishment while you move into retaliatory range. At the moment, the only 'mechs that have the range advantage are those armed with Gauss Rifles, LRMs, or ER PPCs, and that's at the extreme envelope for all those weapons.<br/><br/>In this case, probably the smartest thing to do would be to maneuver towards rough terrain or trees, which tend to give Hovercraft fits; Vedette tanks only have an AC/5 and Machinegun, and they're slower than the Harassers and Condors, making them comparatively easier targets.