Get yourself an antenna tuning unit (ATU). If doing receive only you will need a manual type as the automatic ones need a few watts of tx power to detect a bad match.
You can use the VNA to help tune to a particular frequency. The closer the original match is to the outside of the Smith chart the harder it is to match and the narrower any tuning will be.
Btw, hugging the outside of the Smith chart does NOT indicate loss. It indicates reflection. Loss tends to make the match look better than it really is.
HexAndFlex