Suffkunchris

I've changed head units recently from the standard disc & tape deck, admitedly it's a vague brand cheap'sh 7" screen DVD/CD/Radio. The standard unit held signals really well with the aerial rear screen wired job but the new one won't get radio 1 and is hit and miss with local stations when moving. I assume a signal booster or external aerial would improve the situaton. Anyone had any experience with these?