antenna ups and downs

Hi everyone.Just wondering,I noticed my antenna retracts to a point down inside where it can't be seen any longer. Is this normal? On my friends 78 vette, it stops when the little knob at the top hits the the hole and seems to seal it.I seem to think mine is retracting too far and will allow water in.What do you all think?
Thanks Jules

It's not a water tight seal. Water will get in to the same areas no matter where it stops. Most of the ones I have seen drop below the surface.

There is a grommet seal made for this open area. It is rubber, and fits over the end tip of the antenna. When the antenna is lowered, it completely seals the opening. Your antenna has to be set right on the lowering side for it to work effectively, and complete the seal. I did not know they existed until a C3VR member sent me one. He does not have any more, as we scrounge the country looking for C3 power antenna parts. Sometime we get lucky, but parts are few and far between. I would suggest looking at different rubber grommet type seals, etc., and you may be able to find something to adapt to that exit area.