Malaysian Journal of Analytical Sciences Vol 19 No 5 (2015): 1093 - 1098

 

 

 

RADIO FREQUENCY INTERFERENCE: THE STUDY OF RAIN EFFECT ON RADIO SIGNAL ATTENUATION

 

(Interferens Frekuensi Radio: Kajian Kesan Hujan Pada Pengecilan Isyarat Radio)

 

Roslan Umar^1,2, Shahirah Syafa Sulan³,  Atiq Wahidah Azlan³, Zainol Abidin Ibrahim⁴,

Wan Zul Adli Wan Mokhtar⁵, Nor Hazmin Sabri⁶*

 

¹East Coast Environmental Research Institute (ESERI)

²Faculty of Contemporary Islamic Studies

Universiti Sultan Zainal Abidin, Gong Badak Campus, 21300 Kuala Terengganu, Terengganu, Malaysia

³School of Ocean Engineering,

Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia

⁴Physics Department, Faculty of Science,

Universiti of Malaya, 50603 Kuala Lumpur, Malaysia

⁵Department of Physics, Faculty of Science and Mathematics,

Universiti Pendidikan Sultan Idris, 35900 Tanjung Malim, Perak, Malaysia

⁶School of Fundamental Science,

Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu, Malaysia

*Corresponding author: norhazmin@umt.edu.my

 

 

Received: 14 April 2015; Accepted: 9 July 2015

 

 

Abstract

The intensity of radio waves received by radio telescopes is always not subject to human control. In the millimetre band, the propagation of the electromagnetic waves is severely affected by rain rate, dust particle size and drop size in the terms of attenuation, noise and depolarization. At the frequency above 10 GHz, the absorption and scattering by rain cause a reduction in the transmitted signal amplitude which will lead to the reducing of the availability, reliability and performance on the communications link. In this study, the rain effect on radio signal has been investigated. Spectrum analyzer and weather stations were used to obtain the RFI level and rain rate data respectively. The radio frequency interference (RFI) pattern due to rain factor was determined. This will benefit radio astronomer in managing sites for radio observation for radio astronomy purposes. 

 

Keywords: Radio Frequency Interference (RFI), rain effect, radio signal attenuation, radio astronomy

 

Abstrak

Keamatan gelombang radio yang dikesan oleh teleskop radio sentiasa tidak tertakluk kepada kawalan manusia. Dalam jalur panjang gelombang milimeter, perambatan gelombang elektromagnet terjejas teruk dengan kadar hujan, saiz zarah debu dan saiz titisan dalam terma pengecilan, hingar dan penyahkutuban. Pada frekuensi gelombang radio melebihi 10 GHz, penyerapan dan penyerakan oleh hujan menyebabkan pengurangan amplitud isyarat yang dihantar yang akan mengakibatkan gangguan isyarat dan prestasi hubungan telekomunikasi. Dalam kajian ini, kesan hujan pada isyarat gelombang radio telah dikaji. Penganalisa spektrum dan stesen kajicuaca digunakan untuk mendapatkan nilai RFI dan kadar hujan. Corak interferens frekuensi radio (RFI) yang disebabkan faktor hujan ditentukan. Ini akan memberi manfaat kepada ahli astronomi radio dalam menentukan lokasi untuk cerapan radio untuk tujuan kajian astronomi.

 

Kata kunci: Interferens Frekuensi Radio (RFI), kesan hujan, penurunan isyarat radio, astronomi radio

 

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