billcalley wrote:
I realize that dipoles are balanced antennas, but does the rig
itself still need an RF ground too?

If your feedline is balanced, that is it has equal and opposite currents
on the two conductors, then there's no current left over to flow to or
from ground and no need for an RF ground connection. All the current
from one conductor goes back on the other. Feedlines can be balanced
even if they're coax and/or the antenna is unsymmetrical; they can be
unbalanced even if the antenna and feedline are symmetrical.

If the feedline isn't balanced, the difference current (that is, the
difference between the currents on the two feedline conductors) will
find its way to ground however it can. This often creates undesirable
effects. But if you can't avoid it, it's better to provide a low
impedance path for the ground current if possible. And that can
sometimes be difficult to do.

(I know the radio always needs a DC
ground, of course).

No, it doesn't. It needs an AC safety ground if connected to the mains,
and a lightning ground if that's a possible hazard. But DC isn't important.

How about if the dipole is being used as a
non-loaded "all band" antenna (IE: RIG--TRANSMATCH--LADDER
LINE--DIPOLE) -- would this affect the need for an RF ground on the rig
for operation in the dipole's non-resonant bands? Or is no RF ground
_at all_ required with a dipole; unlike when using random wires or
verticals, and other such un-balanced antennas?

The trick is to get the feedline balanced on all bands. That requires
either a truly balanced tuner, or a combination of a good balun and
impedances on all bands at the balun which the balun can handle.

Roy Lewallen, W7EL