Accession Number : AD0681637

Title :   THE USE OF EXTERNALLY MOUNTED PREAMPLIFIERS IN ANTENNA ARRAYS FOR THE METER BAND,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Dagkesamanskii,R. D. ; Ivanov,S. N. ; Ilyasov,Yu. P.

Report Date : 10 JUN 1968

Pagination or Media Count : 20

Abstract : The purpose of the article is to refine existing calculations of the gain and sensitivity of antennas used for high-resolution radio telescopes by taking into account the influence of the internal noise temperature of the antenna elements and the influence of the number of preamplifiers and their parameters on the sensitivity of the antenna as functions of the real noise and other characteristics of the receiver and of the feeder system. It is demonstrated first the best improvement in the antenna gain is obtained by using as many external preamplifiers as there are antenna elements. The possibility of reducing the number of preamplifier without noticeable loss of gain and the best connection points for the preamplifiers are then investigated. A method is proposed for determining the minimum number of preamplifiers and their connection points for a prescribed loss of sensitivity. Methods of compensating for differences in feeder characteristics are discussed. The statistical nature of the galactic background encountered in radio telescope operation is described and its effect on the sensitivity of the antenna array at meter wavelengths is analyzed. The results are used to estimate the increased sensitivity of the east-west line of the DKR-1000 radio telescope, ensuing from the use of external preamplifiers. (Author)

Descriptors :   (*PHASED ARRAYS, *RADIO TELESCOPES), PREAMPLIFIERS, GAIN, NOISE(RADIO), EXTRATERRESTRIAL RADIO WAVES, SENSITIVITY, USSR

Subject Categories : Astrophysics
      Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE