If an advanced civilization is trying to communicate with another across the vastness of galaxies then they would deliver these data packages in sub atomic particles like neutrinos. Download the same message in trillions of neutrinos scatter them from the base outwards in diaspora to collide with  planets in a random net relying on a sufficiently advanced civilization that knows particle physics to unravel the message hidden within the particle, perhaps with the recipe to create a reply. BAM! Contact. Forget radio waves. That is how i would communicate but scientists are too data driven and rational to think in the abstract like this.