Transhorizon VHF TV signal propagation over mixed land-sea paths

Author

Prasad, M.V.S.N. ; Sharma, Suresh ; Sain, Mangal ; Reddy, B.M.

Author_Institution

Nat. Phys. Lab., New Delhi, India

Volume

38

Issue

1

fYear

1992

fDate

3/1/1992 12:00:00 AM

Firstpage

33

Lastpage

37

Abstract

The propagation characteristics of Rupavahini TV transmissions originating from Sri Lanka on channels 5 and 8 and monitored in southern India are studied. The receiving sites are chosen to provide mixed land-sea paths. The propagation characteristics of these mixed paths are influenced by sea-surface refractivity gradients and land-sea interactions. The analysis of the data indicates that different propagation mechanisms prevail for various percentages of time. Sometimes signal levels on the order of 10-dB below free space level are also observed, particularly in premonsoon months, which is due to the occurrence of ducting conditions prevailing in this region. Some observations of the distance dependence of the channel 5 signal show that the path loss increases by 10 dB for every 100 km of distance

Keywords

electromagnetic wave refraction; radiowave propagation; television broadcasting; tropospheric electromagnetic wave propagation; Rupavahini TV transmissions; Sri Lanka; VHF; channel 5 signal; channel 8; ducting conditions; free space level; land-sea interactions; land-sea paths; path loss; premonsoon months; propagation characteristics; sea-surface refractivity gradients; signal levels; southern India; transhorizon TV signal propagation; tropospheric propagation; Adaptive arrays; Antennas and propagation; Broadcasting; Frequency; Laboratories; Land surface; Monitoring; Sea surface; TV interference; Transmitters;

fLanguage

English

Journal_Title

Broadcasting, IEEE Transactions on

Publisher

ieee

ISSN

0018-9316

Type

jour

DOI

10.1109/11.127424

Filename

127424