@Ca49
As @Annie+UK indicates, that's referring to the digital terrestrial television tuner built into a TV set. 'Please check Antenna connection' is a clue: no Sky hardware uses such a thing in normal operation*.
Sky boxes never need to scan for channels: on the satellite platforms every possible channel is already arriving at the dish, while the streaming platforms request data each time an individual channel is selected.
*Sky Glass contains a DTTV tuner for use when there's no internet connection.
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Sky Glass 55" (on ethernet) & two Stream Pucks (one ethernet / one WiFi)
BT Halo 3+ Ultrafast FTTP (500Mbs), BT Smart Hub 2
