from the late 1970s, the australian regulator had been closely following developments in the us, britain and europe, as to the various competing am radio stereophonic broadcasting technologies. commercial fm radio in australia was still nascent and the commercial am radio incumbents had not yet awoken to the great threat to their viability that fm radio would play in the future. but with the implementation of the geneva plan in late 1978, am channel spacing had been reduced from 10 khz to 9 khz, with some potential loss of fidelity in terms of audio bandwidth. all the am stereo systems under investigation offered not just stereo reproduction but also wider audio bandwidth receivers. the us's fcc chose not to select a particular am stereo technology, but rather approve a number of systems and let the market decide. australia did not follow that path and selected a particular system. sadly, sales of am stereo receivers in australia were miniscule. australian am stations did deploy the technology for the next decade, but this seemed mainly to be able to promote the theory rather than the practice. most am stereo exciters had been switched off by 2000 and none are now operating.