Njay is right. What bands do you want to listen to? If a great majority of the activity in your area is on one band, then get an antenna specific to that one band. And Height is King. Like when you were growing up, you wanna get high.The type of radio has very little to do with what antenna is best.
It is more about the bands you want, the space you have, the money you spend.
There simply is no good single answer.
since this is a Uniden scanner you need a SMA connector equipped antenna per the owners manual.What is the best base antenna for a Br 330t?