The real media of transmission is gravity. As we control gravity we can also use it to transmit pulses of gravity to all directions like waves in a pond. Gravity knows no distances, it doesn't diminish over time or distance.
The problem on Earth is they don't recognize the ether, so they are limited to the "material" side. Using only the material side you can't travel faster than light and you can't transmit anything faster than light. It can't be achieved without gravity manipulation.
This is the way 5D advanced interstellar civilizations communicate with one another…gravity.