Topband: electrically shortening a tall grounded tower

[Bob Kupps]

Hi
Is there any effective way to electrically shorten a tall grounded tower to 1/4 wave? I tried modeling a 1/4 wave cage surrounding the tower but it still shows a lot of current in the protruding section with resulting high angle radiation. Then I tried modeling a 1/4 wave stub above the cage grounded at the top to the central tower which appeared to turn it into a dipole and still significant current above the stub. I was also thinking of using an external parallel resonant trap/choke but would this actually work when situated at a zero current point at the far end of a 1/4 wave monopole?
Thanks and 73 Bob N6BK/HS0ZIA