Previously in Jupiter we were given free radar when colonising so you never really needed to build more than two Comm Sats.
Currently you need to build Comms in each system to see radar but it is limited to what you can see and isn’t so great from a QoL perspective.
It is important that Comm Sats have some use more than in Jupiter but maybe not so much as to have them built in every system you own just to get radar as Comms give you more functions than just radar.
After a little discussion it seems there may be 2 alternatives:
Make a lower level Radar Station option that costs less and only gives you access to system level radar
Make the Comms Sat show the adjacent systems ie the 8 surrounding.
Option one is easily doable and without needing launch site makes it an easier option.
Option two seems doable as per the bug that let you see other galaxies in the outer rims. It seems it may also give more tactical options, spread out enough across a galaxy and you can see everything, more mingling in systems, take out a Comms planet and blind an enemy in multiple systems for any incoming attacks.
Edit maybe give it a new name rather than radar