Okay, bad analogy. The HARM missile goes after radar. However, the AMRAAM supposedly has the ability to target ECM trasnponders, so there is a real-world counterpart to this.

So, has there ever been a canon weapon that targets ECM generators?

HARM goes after almost any "radiation" source (or so say the name), but its primary target is radars yes.

http://en.wikipedia.org/wiki/Anti-radiation_missile

Both the AMRAAM and the R-77 have home-on-jam modes. What both modes o the missile do is greatly complicate defensive use of and ECM your aircraft might be carrying. Of course, if you are foolish enough to leave your ECM on, then that greatly simplifies the job of the aircraft firing on you.

Yeah, but the point of the thread is: can you do this in SR?

I mean, it seems like flooding the battlefield/target building/alley with ECM could really mess up any drones/riggers/TMs that you're fighting against... but there has gotta be a drawback to that, right? Right now, I see this as being the drawback.

You could try something like:

Weapons with HoJ guidance cost more $.
They can be fired without a lock on.

They pick out the strongest non-friendly ECM in the area and attack. They get a bonus to hit of the ECM rating/2 (round up).

So, for example, this would let you fire a bunch of HoJ mortar rounds into the area you wanted to deal with, the rounds are self guiding (have a pilot rating) and HoJ mode. They seek out the highest rated unfriendly jammer and attack.

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Of course, this depends on how 'future warfare' you want to run things. The problem with going too far in this direction is that it becomes largely a game of button pushing and electronics. If you don't have the right electronics, you are dead. If you do, they you push the button, wait and little while, and the 'you win' screen pops up.

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"old" rigger3 has a silencer aarm thats just the item requested.

but those are old rules, and how to go about converting it to SR4 i dont know anything about...

maybe it will show up in the next couple of books?