Yu. I. Belov

Diffraction model of ionospheric irregularity‐induced heater‐wave pattern detected on the WIND satellite

High frequency (HF) radiation from the HAARP and SURA ionospheric heaters transmitted through the underdense ionosphere and received by the WIND satellite show the presence of strong spatial structure in the radiation pattern. A simple model based on the combination of ionospheric irregularities and interference effects has been developed to account for the observations. The analysis demonstrates the utility of satellite receptions as probes of ionospheric irregularities created or enhanced by powerful HF radio waves.

Sura-wind radar: Studies of nonlinear effects using VHF-wave occultion of the ionosphere

We present experimental results on reception of VHF signals of the transmitting facility “Sura” of the Radiophysical Research Institute by the NASA spacecraft WIND. The experiments were performed during daytime during the summer seasons 1997–1998. The dependence of power and spectral characteristics of the VHF radio waves on the power of the sounding radiation is analyzed. We find that, in a wide range of effective powers of the VHF radiation from about 40 kW to 160 MW, the phenomena observed in the radiation received onboard WIND (such as focusing, scintillations, or frequency deviations of signals) does not usually depend on the operation mode of the “Sura” facility. At the same time, broadening of the radiation pattern of the facility and decrease of the mean level of the received signal by about 6 dB toward the direction of maximum of the radiation pattern were observed at the peak radiation power of the facility. The experimental results are compared to present concepts on effects of self-focusing instability and nonlinear defocusing of VHF radio waves in the ionospheric plasma.

Aspherical single-lens objective for radio-vision systems of the millimeter-wavelength range

The characteristics of a system for video imaging of objects in the 3-mm-wavelength range are presented. A calculation procedure and characteristics of an aspherical single-lens objective that is used for imaging (point scattering function, resolution, and field of vision) are presented. An 8 × 8 array of antenna elements that are loaded with detectors is used for the detection of signals in the image plane. A digital processing unit is used for the detection, control, and input-output of electric signals that form the image. The processing and data-transfer rates of the unit are presented. Test experiments on imaging of simple objects (one or several metal spheres with different diameters) are performed in the active radar regime using the proposed system and monochromatic signal.

'Starya Pustin', a historical radio-physical polygon of NIRFI and its potential for a 32 m radio telescope antenna for VLBI

The paper describes in outline format some historical achievements as obtained with different radio telescope antennas built at Staraya Pustin, and describes some of the current developments. The Radio-physical Research Institute (RRI or NIRFI in Russian) at Nizhny Novgorod is responsible for the Staraya Pustin facility. The main subject of the paper is a description of the possibility of constructing at this facility a 32 m radio telescope antenna, suitable for very long baseline interferometry (VLBI) and stand-alone radio astronomy. Similar 32 m radio telescope antennas have been realised already at Svetloe (near St. Petersburg), Zelenchukskaya (North Caucasus) and Badary (near Irkutsk).

The application of correlation analysis in the process of pointing calibration of 64-m Bear Lakes radiotelescope (Russia)

Some specific features of every radiotelescope design have an effect on the construction of a regular errors pointing model (corrections) as a function of the radio source coordinates observed. This corrections are related to the azimuth-axis tilt, nonorthogonality of the azimuth and elevation axes and to other reasons. For the purpose of spacecraft tracking in deep space it is very important to set up an accurate corrections model. The present contribution presents some a method of analysis to determine the regular errors of the 64-m radiotelescope pointing.

Study of an angular radio axis displacement model for 64-meter TNA 1500 radio telescopes (Russia)

A model taking into account the technical characteristics of the mechanisms, constructions, and devices of angular control has been developed to standardize systematic angular errors in the guidance system of 64-meter TNA 1500 radio telescopes. To define the structure of the experimental spectrum of systematic errors obtained from the data on the complex radiometric angular standardization of the radio axis, we used an approximation algorithm based on the least squares criterion for the set of functions which follows from the proposed model of corrections.

FIRST RESULTS OF MILLISECOND PULSAR 1937+21 TIMING BY TNA-1500 RADIO TELESCOPE OF SPECIAL RESEARCH BUREAU OF MOSCOW POWER ENGINEERING INSTITUTE

Regular timing observations of the millisecond pulsar PSR 1937+21 at a frequency of 610 MHz by means of the TNA-1500 radio telescope with a fully steerable 64-m antenna have begun at the Bear Lakes Radio Observatory of the Special Research Bureau of the Moscow Power Engineering Institute. A 40-channel spectrum analyzer and a system for high-speed recording and acquisition of observation data are connected to a reference clock by means of CAMAC interfaces and an 80286 control computer. The reception band is 1.6 MHz (40 channels of 40 kHz each). The total noise temperature of the system is on the order of 160 K. The signal-to-noise ratio is on the order of 50 for a 30-min observation of the pulsar. The mean-square error of measurement of the pulse arrival time is 400 nsec. Data on pulsar 1937+21 along with timing results for “normal” reference pulsars PSR 0834+06 and PSR 1919+21 obtained at the Pushino Radio Observatory of the Lebedev Physics Institute over a period of 13 years will be used to construct a pulsar time scale.