We compare observations made by the Pioneer Venus Orbiter plasma analyzer and the plasma wave instrument in the Venus ionosheath. Large increases in plasma wave turbulence levels appear to be connected with changing plasma distributions and interpenetrating plasma beams. We identify some of these plasma waves as Doppler-shifted ion acoustic waves due to beam/beam interactions, but different forms of instabilities are probably also operative. The changes in the temperature, intensity and energy of the peak in the PVO plasma distributions are similar to those observed by Venera 10 closer to the planet and appear to be evidence for rarefraction and compression in the downstream ionosheath. Some of the changes in the PVO plasma distributions may be related to the presence of a second ion population or the acceleration of protons.