INTRODUCTION The High Harmonic Fast Wave (HHFW) system on NSTX is used for plasma (electron) heating and current drive. It consists of twelve current straps powered by six 1-MW transmitters operating at 30 MHz, with straps 1&7, 2&8, ... connected by 2! of transmission line and oriented to have opposite currents [1]. Thus, straps 1-6 and 7-12 form two phased arrays which are permanently 180o out of phase with each other; the phase shift between transmitters can be rapidly and arbitrarily varied during a pulse. For relative phase shifts of ±30o, ±90o, and ±150o, the launcher operates as a highly directional, 12-element array with spectral peaks at k|| ~ ±3, ±8, ±14 m -1 respectively, where k|| is equivalent to n"/(R+a).