This paper gives a detailed quantitative analysis of the high-frequency spontaneous wave emissions produced by an electron beam injected into the ionospheric plasma. A general discussion about individual-collective and incoherent-coherent characteristic of the emissions is given. Then attention is focused on the spontatneous coherent emission in three different modes: plasma waves, Bernstein modes, and electromagnetic whisler mode. Comparisons with experimental results obtained by several experiments (electron echo experiment, Araks) are made throughout the paper and suggest that many experimental features are well interpreted in terms of coherent emission.