On Fri, 17 Feb 2006 15:35:30 +0000, Kate wrote:

I'm beginning to think that the vertical bars might not have much to
do with it. The long, horizontal bar seems much more like the culprit.
Are the ends sealed with no air access whatsoever?

Possibly the bars are hollow tubes with open ends. The wind blowing
across the tops would be like blowing across the tops of empty milk
bottles.

Check the ends of the bars, block them off if they are hollow and see
what happens.

sponix