Had the same issue with my '04 Sonata. Bought a new antenna on Craigslist for $40, including shipping to my house. Its actually a fairly easy replace. But you will have to do the work from the trunk, as it is located above the rear driver side wheel well. The problem with the original antenna is the plastic or nylon retractable cord that pushes up the antenna, as well as, retracting it gets twisted or misaligned from the motor. Thus causing the motor to continually turn thinking the cord isn't fully retracted, when really it has been. That's the clicking noise you hear as its retracted, and also when its extended. Replacing it eliminates the cringe you feel when you accidentally turn on the radio, off as well, and hearing the annoying sound of the antenna clicking. Hope this helps. Good luck.