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directions, At b is the vertical polar diagram, showing how the
radiation varies from maximum at right angles to the dipole to nil
end-on. So if a dipole is placed horizontally it can be used to cut out
undesired reception from two opposite directions. As regards
reception, these diagrams assume, of course, that the radiation
arriving has the correct polarisation. A horizontal dipole does not
respond to vertically polarised waves from any direction.
17.10 Reflectors and Directors
Any metal rod is a tuned circuit which will have maximum currents
set going in it by waves twice its own length. These currents radiate
waves, just as if they