Tnx a lot Bill and tnx again to everyone helps me.
I received many emails and now I know the right thnig to do.
The right manual is August 1998 (another version May 1999 reports same
element's lenght).
This is for improving any possible SWR problem in 15 meters with the
first version on X7 antenna.
Tnx a lot again.
See you soon on the air.
Pasquale IW0HEX