On 3/16/2010 5:57 PM, ai8o wrote:
I am thinking of making a 2 meter J-Pole from 3/4 or 5/8 copper pipe.

Most plans that I can find on the web call for a 58 inch main leg and
a 20 inch support below, making the antenna
78 inches or so in height.

I want to install it in my attic where I have 66 inches of clear
space.

Can I cut the lower support leg down to 8 inches without a major
impact on the performance of the antenna?

The support leg is just that a leg. You can make it any length that
works for you.

John W3JXP