First describe the aerial installation... Where it comes into the home, what bits there are (amplifiers, aka boosters, or splitter and where thay are located to distribute the signal to cables and/or sockets in the room(s).
Plus Location - roughly where you are so we know which transmitter(s)/frequencies and hence TV channels are likely to be received.
Then we stand a chance of giving some suitable useful advice.
NB Start by taking the TV back downstairs to tune it in on the incoming aerial feed. Then don't retune it again when back upstairs as it will help with diagnosis.
Unless you are in a funny location where, for some odd reason, two transmitters are received and one used down with another upstairs.
93 channels found should mean you get 93 - albeit some poorly with breakup. As 99% of problems are caused by poor connections and cables look over them all with a critical eye.