A systematic study was made of some of the oscillatory phenomena which are found to occur in bounded dc discharge plasmas. The nature of the oscillator patterns was explored over a pressure interval (0.01≤P≤1.5 Torr), a current interval (0.5≤I≤10 mA), and a discharge‐voltage interval (0.8≤V≤3.5 kV) in order to establish the conditions for onset of oscillatory modes within the plasma. An rf pickup coil, to detect the oscillations, was placed such that it contained the plasma filament coaxially. Signals having a frequency range of 20–200 kHz were observed to be coming from the plasma. These frequencies were found to be sensitive to pressure, current, and discharge voltages for a given geometry tube. The gases considered in this investigation were N2, O2, CO2, air (atmospheric), H2, D2, He, and argon. Electron densities calculated from the ``resonant'' conditions for the ions are presented.