@thucydides, I'm no expert either so I can be wrong aswel, but you'd be surprised by how little power you need to transmit into space. That satellite we shoot into space to find ET's, the one that exited our solar system some time ago has only 25W iirc. Remember, they don't have to decode it, they just need to detect radiation that isn't natural.
I do admit I forgot that it propagated at the speed of light, so good call on that. So it'll probably be some time before the nearest star can pick it up. Unless they use shortcuts in the space-time continuum. (interstellar!)
I'm sorry, I don't understand what you're trying to say with the Great filter
@mitchel, i don't think we have a 4

reality. Can you 'see' time? who is telling time is the 4th dimension? for all we know it's something else. yes, i know, you can see time as the 4th axis with this current state now at the origin. But time is relative, it's something we invented in our perspective.
Again, I'm no expert, i'm saying what I'm making of it. I would love to read a book about it though.