Simple answer … make something with the power of a very bright quasar (10^40W), in our distance the energy flux is like 10^-14 W/m^2 … convert big part of the power to radio at some Mhz-Ghz band or similar , so it is very bright at some specific band, to grab attention.
According to this http://www.pnas.org/content/pnas/96/9/4756.full.pdf the flux densities observed are of order 0.1 Jansky (Jy) at 1,400 MHz, where 1 Jy = 5x10-26 W/m^2/Hz, so if you spread that 10^-14 W/m^2 over 100 MHz, the flux will be ~ 10^-21 W/m^2/Hz, likely very bright for an extragalactic object.
Once you get the attention on radio, modulate optical spectra so it does not match periodic table, but is e.g. some binary code. First sightoptical attention-grabbing may be also to artificially create some impossibly high red-shift spectra.
Simple answer … make something with the power of a very bright quasar (10^40W), in our distance the energy flux is like 10^-14 W/m^2 … convert big part of the power to radio at some Mhz-Ghz band or similar , so it is very bright at some specific band, to grab attention.
According to this http://www.pnas.org/content/pnas/96/9/4756.full.pdf the flux densities observed are of order 0.1 Jansky (Jy) at 1,400 MHz, where 1 Jy = 5x10-26 W/m^2/Hz, so if you spread that 10^-14 W/m^2 over 100 MHz, the flux will be ~ 10^-21 W/m^2/Hz, likely very bright for an extragalactic object.
Once you get the attention on radio, modulate optical spectra so it does not match periodic table, but is e.g. some binary code. First sightoptical attention-grabbing may be also to artificially create some impossibly high red-shift spectra.
The problem with quasars is that they only emit that much power along their axes, not in every direction.