My intuition says no. I don't think we'll be detecting exoplanet asteroid strikes anytime soon for instance.

Well, someone running a nearby Dyson Swarm might as well run a couple thousand telescopes when they are at it, even to just make really sure no habitats are ending up in collisions with comments and extrasystem asteroids. In spare time such system could be used to look for interesting stuff in other systems, possibly like a big synthetic telescope of some sort.

its inverse square falloff for radio energy dissipation so I'd say it goes away really really quickly. also you have the problem of overcoming Sun's 'blaring' background signal unless you took your signal generator and placed it outside of oort cloud or further.

Yes, why not the oort cloud! It might take a decade or two to get them out there, but completely within our current technical capabilities.

oort cloud is just a stand-in for generating enough parallax in the signal from sun. further out you go better it would be. in fact it just occurred to me that you could just launch an emitter perpendicular to galactic plane with enough velocity that it bobbles up and down say 3x over what a normal star would and it would serve as a galactic lighthouse for intelligent civilization.

Another idea is to put a mylar parabolic mirror behind the bombs. A very short burst of light is going to get focused in a beam before the mylar is vapourised. Maybe someone smart here could calculate exactly how short the beam would be.

That short burst could be in itself a significant signature. What, in nature, could produce such a short concentrated energy burst?

problem with such a tight-beam is you have to be in direct line of sight for it to be seen. which means a very small number of receivers civilization can ever know, that is exact opposite of the goals of a 'lighthouse'. perhaps something that sweeps around at regular intervals with some precession thrown in for coverage, that makes it closer to GP's comment about neutron star emitting prime numbers.