Changes in the characteristics of the electron beam and the associated wave spectrum as a function of axial distance from the electron gun have been studied in a steady state laboratory beam plasma discharge. The beam energy distribution evolves from a monoenergetic beam to a heated beam (characteristic of trapping) and then to an almost flat (plateau) distribution with increasing distance from the gun. The wave spectrum evolves similarly from a small amplitude single band at the upper hybrid frequency fUHF=(fp 2+fc 2)1/2 to a much larger amplitude, harmonic rich spectrum with increasing distance. Accompanying the degraded energy spectrum, the valleys between the harmonic peaks disappear to produce a continuous spectrum greater than fUHF with reduced amplitude. Very little spatial diffusion or pitch angle scattering of the beam is observed, indicating that the interaction is predominantly one-dimensional. The axial positions, where these different wave-beam electron configurations appear, depend upon the experiment parameters, beam current Ib, beam energy Eb, and neutral density. The described results clearly indicate the occurrence of the absolute rather than the convective instability and confirm that the beam plasma discharge (avalanche ionization) is a particular manifestation of the well-studied strong beam-plasma interaction (avalanche ionization absent).