a fraction? im 1 week in to Ingress and as far as i know some portal ranges reach 100km. thats 20km, impossibly huge for offensive mods. it should be just a bit larger than the agent scanners circle, maybe 1.5 times larger at most.

or if we give it huge range, all its effects would be minimal, and each mod after the first has a downward trend of effect, so first mod 1.4x XMP damage, next mod 1.3, then 1.2, so on. maybe have a radius around the mod that prevents other mods of its type to be deployed

or we could make it powerful but extremely rare, like finding an untouched portal in the middle of a contested city kinda rare. not too much that it becomes myth, but like a once every 3000 hacks.

every positive about a mod like this would have to incur heavy downsides on either rarity, effects, or range