Richard Clark wrote:
I would point out, however, that antennas intended for even harmonics
(40M/20M) usually portend disaster. I suggest you research the net
for "fan dipole." That you do not report any such disaster suggests
that due to what you DO report (unequal length dipole legs) suggests
that you have is what is called an OCF (off-center feed) dipole.
This
makes yet another variable that tends to throw a spanner in the gears
of tuning. In this regard, you need to research the net for the
topic
of "feedpoint choke" or "W2DU style BalUns."

Richard,

Probably I missed telling the list that, the coax feeds a 1:1 balun
which is connected to the dipole. The dipole is center-fed, and balun
feeds both both 20m and 40m wires of the dipole.