Arrays of edge magnetic coils and statistical analysis techniques have been used to investigate the magnetic fluctuation structure in the HBTX-1A reversed field pinch. The superficially random fluctuations can in fact be attributed almost entirely to global modes with poloidal mode number m = 0 and 1, provided account is taken of toroidal distortion of the modes. A toroidal array of coils discloses a broad spectrum of toroidal mode numbers with peak at |n| ∼ 10 and significant variation with time and frequency. Cross-correlation establishes that |n| ∼ 10 corresponds to m = 1, a helical mode resonant inside the reversal surface, and also shows the presence of m = 0, n ∼ 0. The time-scales of the fluctuation indicate that the instabilities are probably resistive in character, and the mode amplitudes are such that island overlap and magnetic field ergodization should occur. The energy confinement time due to stochastic transport, estimated from the measured fluctuations, is consistent with that observed experimentally.