A.V. Levsha, R.Y Ryaskin, V.А. Shashlov

Feature of functioning of radio lines in the HF range is high level of inadvertent hindrances, and also a large number of working radio stations that compels to resort to a radiomonito-ring and search of frequencies. Along with casual hindrances in a reception path of the radio-receiving devices such nonlinear phenomena as intermodulation hindrances which are registered as external signals are observed and distort real alarm and interfering a situation. The accounting of this fact gives the chance to develop new algorithms of a choice of working frequencies at a stage of radiomonitorin-hectare, planning and purpose of a grid of in advance prepared frequencies and possibility of reduction of level. For confirmation of theoretical preconditions practical experiments were made. At the expense of reduction of quantity of intermodulation hindrances and decrease in their level the number of the frequencies meeting requirements increases.