Radioastrophysical Observatory ISTP RAS SB

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RADIOASTROPHYSICAL DEPARTMENT • INSTITUTE OF SOLAR-TERRESTRIAL PHYSICS RAS SB

SSRT - Receiving systems

The SSRT has two independent receiving systems for recording solar observational data, and several ancillary receivers for checking, setting up and adjusting the instrument.

The base receiving systen is a multichannel filter receiver for a simultaneous recording in 180 channels with the 500 kHz band each, adjusted at steps of about 600 kHz. Recordings with this system are accomplished in either of two modes: the transit one-dimensional mode by recording the response of one of the linear interferometers with a time resolution of up to 14 ms, and the two-dimensional mode using a classic procedure of signal multiplication by means of phase modulation.

Main characteristics of the base receiving-recording complex

	Name	Quantity
	Noise temperature of the receiving complex	3000 K
	Maximum gain	136 dB
	Dynamic range at a fixed position of attenuators	10⁴
	Control range of the input signal level	40 dB
	Control range of the signal level for intermediate frequency	28 dB
	Time constant of the channels	0,13 sec; 0,7 sec
	Amplification instability	< 2 %
	Sample rate	up to 100 Hz
	Channel's band	500 kHz

The other receiving system is an acousto-optic spectrum analyser spectrum analyzer with the 28 MHz band, divided by 96 channels. The total receiving band is sampled consecutively in 4 steps (112 MHz - 384 channels). This receiving system was used to carryout an additive-corelation processing of signals to obtain, concurrently with radio maps, also one-dimensional radio brightness distributions (also Stokes parameters I and V), with 56 ms resolution. Curently this system is employed to take continuous records in the two-dimensional mode. Its sensitivity is still four times lower compared to the filter receiving system because of a consecutive signal processing in the total reception band.

Calibrations

The orinetation of the SSRT beam was tested in obseravtions of the 3C273 quasar. Observations of the Moon were used in calbrating the instrument for the flux. Auto-calibration from recorded solar radio maps is in current use.

Data archive and databases:

one-dimensional radio brightness distribiutions in two directions (from the linear E-W and N-S interferometers) for the entire observing time at intervals from 2.5 to 40 min

two-dimensional radio maps - every hour + all input data

tabulated data: coordinates and fluxes of active regions and flares

burst observations: all information is stored (where possible)

Publication of data

Since 1996, monitoring data from the SSRT have appeared in a regularly published international "Solar Geophysical Data" bulletin. Since 1988, one-dimensional midday scans, obtained at the SSRT, have been published in this country's bulletin "Solnechnye dannye". Since 1996, a series of solar radio images from the SSRT have been available via Internet at the address:

http://www.eso.org/astronomyonline/market/collaboration/aurora/ssrt.html

Institute's home page address:

http://www.iszf.irk.ru