Complex sentence: High voltage pulses from an induction coil "(T)" were applied between the two sides of the antenna, and sparks across the spark gap excited oscillating standing waves of current in the antenna, which radiated the energy as radio waves.
Split into simpler sentences: High voltage pulses from an induction coil "(T)" were applied between the two sides of the antenna. The spark excited oscillating standing waves of current in the antenna, which radiated the energy as radio waves.