[mndgs]

BS. Though a RPG could travel 1km (not sure), I know for sure that an effective RPG range is 300-400 m, after which accuracy degrades substantially.

And even if you try walking up the fiber cables (if you manage to spot them), you will become a target yourself much earlier than you manage to locate the origin of the fiber, i.e. the drone crew.

So, that wouldn't work.

[LarsDu88]

An automatic grenade launcher firing 40 mm rounds can reach up to 2 km on a parabolic trajectory.

It'd take a lot of grenades, but there are videos from the Ukraine war of Ukranian infantry landing hits at range on Russian positions using drone spotters.