Ohh dear,
You bought one of THEM antennas....
Like yourself I bought one in the late 90's and had no end of problems with it.
What you need before you put this antenna together is a small tube of Loctite and apply it to each and every fastener that you fit to this antenna.
Don't get me wrong, they aren't a bad antenna per se, they just fall to pieces when the fasteners work themselves loose in windy conditions.
Good Luck!