I have no personal experience with your conditions.
However, the scenario is familiar. You would like to "tidy up" an
installation that is "sort of" working.

You can minimize the effort involved by going to
http://free.prohosting.com/~w0rcy/Jpole/jpole.html

That will allow you to plan the fewest trips to the attic that will
enable you achieve your goals with your resources.

OTH, if you are achieving acceptable results with what you have now I
would advise leaving it alone. If you feel 2-4db more is worth the
effort, lay out your plan!

BTW, I totally agree with Cecil. The fundamental problem appears that
the antenna is a bit short! Any change other than that is a patch!

On Mon, 20 Mar 2006 08:12:51 -0700, jimbo wrote:

OK, I have a new 2 meter j-pole antenna installed in my 3rd floor
attic. I have 50 feet of LMR240 coax running to the basement. I
measure SWR at the following frequencies on simplex.

144.2 2.5
145.2 2.4
146.2 2.3
147.2 1.9
147.9 1.7

Can I conclude that the antenna is electrically short for the 2 meter
band?

Thanks for any insight, jimbo
John Ferrell W8CCW