1. Retune your TV
2. Try connecting the TV to a different aerial point and then try again.
3. In many parts of Noosa a TV signal booster is required to provide free to air reception even with a roof mounted aerial. These can be purchased at an electrical store for about $40 and plug into both a power point and a TV aerial point. If there is more than 1 TV aerial point in the house you will need to find the correct point to plug into (It is more often than not the point that is closest to where the aerial is installed on the roof). You don't need to plug a TV into that point if you don't want to, just the booster plugged in to both the power and aerial point and the power switch turned on.