telescopic

I have several very basic telescoping antennas for scanner radios. Would there be any advantage to somehow combining them in series to create a more powerful "single" antenna?

I am looking to go taller with my portable mast. Currently I own a great mast from here, and being 21 feet (6.4 meters) high, I am looking to grab an additional 10 to 20 feet (3 to 6.1 meters). I am not having much luck finding anyone that sells taller telescopic aluminum masts, and it seems...