My old Fetch box had 2 TV antenna ports (in/out) and the new one only has one. I could get excellent Free Tv with it but it needed an ethernet cable to get internet (I couldn't find anywhere in the settings menu to set up wifi).
So with the new Fetchbox, I managed to get that set up thru wifi but still no Free TV. Yes, I tried an antenna (with booster) but it is no good. I shouldn't need one anyway.
Several things you mention there. What is your specific issue? No FTA TV?
Plugging the booster into the one antenna port in the fetch should allow the fetch to scan for FTA channels. If its not getting them then try removing the booster and scan for FTA channels. If still not getting them then try plug the antenna direct in to the TV (bypass the fetch entirely) and scan for channels. If the TV gets channels then your fetch may be faulty.