1990, Articles 11-13) is simple in principle, (modes 7 and 8 in Figures 26.5 and 26.6, including the "quasi although somewhat complex in practice. The administration respon- antipodal" form of mode 8) in the circumstances, SO far relatively sible for a proposed new earth station prepares a map, using agreed rare, in which a band used for up links in one network is used for standardised parameters and techniques, showing the area around down links in the other, and vice versa. the proposed site within which, under worst case conditions, the An administration responsible for a proposed new satellite net- earth station transmitter might cause significant interference to a work publishes the essential technical details up to six years before receiver of the fixed service operating in the up link frequency band. the launch. This is called "advance publication". It draws the atten- A second map is drawn, showing the area within which, under worst tion of other administrations, responsible for existing satellite net- case conditions, a transmitter of the fixed service operating in the works, to possible future inter network interference problems, down link frequency band might cause significant interference to enabling discussions to be held to seek ways of reducing prospective the earth station receiver. These are interference modes 1 and 2 interference before the design and manufacture of the new satellite respectively in Figure 26.3. has progressed too far for changes to be made. If the co-ordination areas shown by these maps include any For a satellite that is not to be geostationary, the frequency assign- foreign territory where there is an agreed allocation of the same ments for the receivers and transmitters on board the satellite can be frequency bands for the fixed service, the two administrations notified to the IFRB for registration in the MIFR when these exchange information on all relevant earth station and terrestrial discussions have been completed, without further formality. In station frequency assignme