I recall reading about this many years ago but can't find it in any of the
books I have now.

How do I couple the meter to the antenna?

The project is a 3-element 2 meter yagi and I'm trying to set the length
of
the driven element. I can't find a dip within the band using the rig and
an
swr bridge.

Tom, N3IJ

The length of the driving element is not critical and may not resonate by
itsself depending on the matching device used.