If it is clicking on the down-stroke, it is because it was not fully extended - from the down position, as it starts to raise, "help" it to extend fully - you will likely find that it is sticking close to one of the joints, where the crud tends to accumulate. Clean it thoroughly then lube it & it should work better. If it is "tweaked" at all, you probably need a new mast or it will constantly stick at that point.
Consider a "smartenna" from Dali so it only goes up for radio reception & not for CD.
[This message has been edited by D'Ecosse (edited 15 December 2002).]