This paper presents multimode waveguide Van-Atta array based on a pair of waveguide radiators. For dispersionless transmission lines we selected 3 coaxial lines, located inside a metal box, which frames the waveguides. Experimental data of monostatic radar cross-section diagram of antenna array in 6-12 GHz in frequency domain are obtained. Experimental study was performed in anechoic chamber of Share Scientific Center “Applied electrodynamics and antenna measurements”, Southern federal university. The subject of research was a model of multimode waveguide Van-Atta array based on a pair of waveguide radiators with aperture size 50*10 mm. An array placed in shield in the form of an elliptical cylinder. This configuration provides an opportunity to decrease ghost reflection from connectors and interconnection cable. A method for compensation background reflections, which experimentally performed on a model of multimode waveguide Van-Atta array, located inside an elliptical cylinder is proposed in this paper. This condition is completely accurate to the real usage conditions. This method is necessary for the research of objects with RCS commensurable with RCS of anechoic chamber. Backscattering diagrams, produced by aperture of Van-Atta array without background reradiation from constructional elements is obtained. The comparison between theoretical backscattering diagrams and results, which obtained by subtraction of experimental data of Van-Atta array with open aperture and aperture closed by radar-absorptive material is performed. Results by this method has shown good match between the numerical and experimental data. This fact confirms the accuracy of the proposed method for processing of experimental data.

Keywords: Van-Atta array, monostatic diagram of radar cross-section, multimode array, mesurements of scatterrin characteristics

The article discusses the relevance of the compact, mobile radio modem sup-ports modern interface USB. The result is the development of a half-duplex tran-sceiver is a device that works with a frequency manipulated signal in a license-free frequency band. The radio modem is equipped with interface USB, through which data is exchanged, as well as its food, as antennas used inefficient quarter-vibrators. Increase in radio range is possible by the use of antennas with high directive gain. Experimental studies of two designed devices were carried out in an urban setting. Their aim was to establish the maximum sustainable radio range (with line of sight) at different data rates as error correction at the reception, and without. Experimenter, away from the transmitting radio modem, monitored the received data. The use of error-correcting coding is most effective at high data rates (up to 3 dB) than at low (1-2 dB). Increase in radio range is possible by reducing the transmission speed - this is due to the dependence of the receiver sensitivity of the speed manipulation. It should also be noted that the decrease in device size is possible by structural modification.

Keywords: radio interface USB, mobile radio, radio communication range, noiseless coding, frequency keyed signal, experimental studies.