A study of HF field strength variation in India and its prediction

Author

Lakshmi, D.R. ; Reddy, B.R. ; Sain, Mangal

Author_Institution

Nat. Phys. Lab., New Delhi, India

Volume

40

Issue

1

fYear

1994

fDate

3/1/1994 12:00:00 AM

Firstpage

38

Lastpage

43

Abstract

Measured field strength data pertaining to several HF broadcast transmissions monitored in India during 1987-90 has been analysed to study solar activity, local time and seasonal variations in the field-strength. Values tend to saturate at high solar activity levels when sunspot numbers are beyond 120. Variations in field strength have also been studied with varying ratios of operational frequency to maximum usable frequency (f_op/MUF) and equivalent vertical frequency of the links. Based on this study a prediction method for HF field strength has been suggested for India. Comparison of values estimated using this technique has been made with actual measured field strength values for different HF transmissions for different months. This method is to be particularly suitable for field operators

Keywords

field strength measurement; ionospheric electromagnetic wave propagation; radio broadcasting; radio links; radiowave propagation; solar activity; HF broadcast transmissions; HF field strength variation; India; equivalent vertical frequency; local time variation; operational frequency to maximum usable frequency ratio; prediction method; seasonal variation; solar activity; sunspot numbers; Broadcasting; Circuits; Electromagnetic wave absorption; Frequency; Hafnium; Ionization; Ionosphere; Laboratories; Monitoring; Time measurement;

fLanguage

English

Journal_Title

Broadcasting, IEEE Transactions on

Publisher

ieee

ISSN

0018-9316

Type

jour

DOI

10.1109/11.272419

Filename

272419