Jim wrote:
i understand that a monopole antenna is an illusion.

Yes and no. An antenna can easily be constructed such that only a
monopole radiates significantly. A common example is a ground plane
antenna. However, the same amount of current which flows into a monopole
must flow somewhere else -- to a ground plane or "counterpoise", to the
Earth, down the transmission line, or to another radiating wire for
example. So a monopole can't exist in isolation.

the element is
reflected by ground or a ground plane or a counterpoise and is
effectively a two element set up anyway.

No, an element isn't "reflected". The field from any antenna, monopole
or dipole, is reflected by the ground, creating interference with the
unreflected field.

so, somebody take me to
school on this; what about a ground plane whip such as a cb antenna with
another identical whip mounted upside down below it?

This constitutes a vertical dipole, a common antenna type.

would the bottom
whip appear equal to a ground plane and allow the antenna to radiate as
it was intended to?

No, it wouldn't "appear equal to a ground plane". As for the antenna
radiating as it's intended to, how do you intend for it to radiate?

would this work in an application where a decent rf
ground cannot be achieved?

Sure. A vertical dipole is a very common type of antenna. A google
search should bring you a wealth of information.

or where consistent antenna characteristics
are needed regardless of location or environment?

The location and environment can affect any type of antenna, including
this one.

Roy Lewallen, W7EL