chuck wrote:
If there are no obvious common mode currents causing problems in the
shack, then of what consequence would an imbalance be, other than to
modify the radiation pattern, perhaps even beneficially?

The purpose of the antenna is to radiate. The purpose
of the transmission line is to transfer the energy from
the transmitter to the antenna with as little loss as
feasible. How much an antenna system is allowed to
deviate from its purpose is up to the individual. When
I was in high school, I didn't much care about the purpose
of an antenna system and burned a hole in my lip.
--
73, Cecil http://www.qsl.net/w5dxp