  We discuss the appropriate normalization of modes required to generate a
homogeneous random field in an open Friedmann-Robertson-Walker universe. We
consider scalar random fields and certain tensor random fields that can be
obtained by covariantly differentiating a scalar. Modes of interest fall into
three categories: the familiar sub-curvature modes, the more recently discussed
super-curvature modes, and a set of discrete modes with positive eigenvalues
which can be used to generate homogeneous tensor random fields even though the
underlying scalar field is not homogeneous. A particular example of the last
case which has been discussed in the literature is the bubble wall fluctuation
in open inflationary universes.
