your current aerial may just need realining…
or you may need a masthead amplifier and pwer supply to help boost the signal.
or if your current aerial is really really old (and is more organic rather than electronc) then yes another aerial may be required.
there are some bright orange televes aerials that are available just abuot everywhere….i use another make that has a few more dbs….but all aerialsl with the correct amplifers and good cable connections and nice “line if sight” to your tdt transmitter will help.