Abstract: In a method of allocating carrier frequencies for transmission within a transmission network, such as a tactical network, the set of carrier frequencies constituting the available frequency resource for the network is broken down into batches of unequal size. At the time it enters the network, as indicated by a request for allocation of a frequency for a link between it and another site (referred to as the first connection for the site), and previous to such allocation, any site of the network is allocated one of two complementary states so as to obtain complementary states for the site in question and for its first connection site. These states are retained for subsequent links between the site in question and other sites of the network. For any link to be set up between two sites of the network, a frequency is allocated at random from the largest batch if the sites in question are in complementary states or from a smaller batch if the sites in question are in the identical state.