I was going to reply that it might be difficult to match the power of something like Jupiter's radio signals. However, it turns out that Jupiter's decametric radio emissions are only about the equivalent of a megawatt antenna[1]. The US air force already has a radar with a peak power of 32 megawatts[2]. So with sufficient motivation, in principle we or an alien civilization could certainly send regular signals like that.

[1] https://www.space.com/26419-jupiter-radio-waves-alien-life.h...

[2] https://en.wikipedia.org/wiki/Eglin_AFB_Site_C-6

Not only could we send those kinds of signals, we already have done it using the Arecibo Telescope (RIP), which h̶a̶s̶ had EIRPs ranging from 200 megawatts to 22,000,000 megawatts depending on the transmission frequency. In 1974, we beamed a short message to the Messier 13 globular cluster with a transmission power of just under half a megawatt.

https://en.wikipedia.org/wiki/Arecibo_message

Converting the output of a narrow-beam transmitter to EIRP for comparison with radiation sources in the universe makes the assumption that the user of the transmitter knows where to point it.