Sal M. Onella wrote:
I have very few ideas for correcting the original sleeve design.

What are the resonant frequencies and feedpoint
resistances for the two types of feeds?

There's no rule that says the antenna must be
50 ohms at resonance. A 2.8:1 SWR could just be
an indication that the feedpoint impedance at
resonance is 18 + j0 ohms.

Did you do anything to choke the common-mode
currents on the feedline? If not, those currents
can upset the SWR meter reading.
--
73, Cecil, http://www.qsl.net/w5dxp