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?

That's what I would conclude from the data given. Wind some
wire around the tip top and extend the antenna by a few
inches. Then repeat your SWR measurements.
--
73, Cecil http://www.qsl.net/w5dxp