I have read online saying that it is possible to complete this quest without seeking help from any of the three factions, but I can't seem to figure out how.

In my quest log i have 3 choices, the 3 (optional) faction choices and "Get help to build the Signal Interceptor". Last step completed with a checkmark is "Return to Virgil"

Opening the workshop in a settlement doesn't give me a "Special" category, and I have confirmed that I have "Signal Interceptor Plans" in my inventory.

Can anyone tell me how am I suppose to build this without the assistance of any of the three factions? Thanks.

I have reached the same issue on this and have been looking around for options to build the "signal interceptor" as well.

Unfortunatly I'm also not making any headway.

Even in the official guide by Prima it says you can build it on your own, but doesn't give you any details.

Is there a companion or a special settler that can help, or maxing out a specific perk or SPECIAL stat?

Has anyone tried to DIY this succesfully that can share information?