Cecil, W5DXP wrote:
"But how about the electromagnetic waves and photons involved with
standing waves?"

Terman has an answer. The standing wave is only a manifestation of
interference between two waves traveling in opposite directions, so on
page 870 of his 1955 opus Terman writes:

"The directional characteristic of a resonant (standing wave) system is
the vector sum of the directional patterns pointed in opposite
directions, as illustrated in Fig. 23-8."

In other words, the wave traveling in one direction produces its pattern
and the wave traveling in the other direction produces its pattern. The
sum of the patterns in both directions is the directional pattern for
the rod or wire. Standing waves have nothing to do with it but to stand
there and do nothing.

Best regards, Richard Harrison, KB5WZI