Cecil. W5DXP wrote:
"A 1/2-wavelength of transmission line reverses the phase of the
current, certainly a 180 degree "transformation"."

Yes. One of the baluns in the ARRL Antenna Book uses an extra180-degrees
of 75-ohm coax to drive an element in a 300-ohm balanced antenna from an
unbalanced 75-ohm aource.

Best regards, Richard Harrison, KB5WZI