Sains Malaysiana 48(1)(2019): 183–189

http://dx.doi.org/10.17576/jsm-2019-4801-21

Radio Frequency Interference on Nearby Radio Astronomical Lines: Relationship between Wind Speed and Radio Signal Strength Measured at East Coast of Peninsular Malaysia

(Gangguan Frekuensi Radio pada Talian Astronomi Radio Berdekatan: Hubungan antara Kelajuan Angin dan Kekuatan Isyarat Radio Diukur di Pantai Timur Semenanjung Malaysia)

SHARIFAH NURUL AISYAH SYED ZAFAR¹, NOR HAZMIN SABRI^2*, ROSLAN UMAR¹ & ZAINOL ABIDIN IBRAHIM³

¹East Coast Environmental Research Institute (ESERI), Universiti Sultan Zainal Abidin, Gong Badak Campus, 21300 Kuala Terengganu, Terengganu Darul Iman, Malaysia

²School of Fundamental Science, Universiti Malaysia Terengganu, 21030 Kuala Terengganu, Terengganu Darul Iman, Malaysia

³Physics Department, Faculty of Science, Universiti of Malaya, 50603 Kuala Lumpur, Federal Territory, Malaysia

Diserahkan: 28 Mac 2018/Diterima: 12 September 2018

ABSTRACT

The East coast of Peninsular Malaysia receives a strong wind speed, heavy rain and high humidity during the Northeast monsoon. The Malaysian Meteorological Department claims that the wind speed during the Northeast season could reach 55.56 km/h or more. This strong wind speed and heavy rain could contribute to the attenuation of radio signals. This paper investigated the relationship between wind speed (km/h) and radio signal strength, RSS (dBm). The statistical correlation was employed to identify the correlation value and strength between them. The wind speed and RSS were collected during wet and dry seasons at Kusza Observatory, while the Spectrum analyser was used for measuring RSS (dBm) and the weather station for wind speed (km/h). The result showed that the wet season has strong and significant correlation compared to the dry season. Frequencies of 382.5 MHz, 945 MHz and 2160 MHz with correlation values of r = -0.583;-0.631 and -0:514, respectively, showed strong, negative and significant correlations with wind speed in the wet season. As for the dry season, only a frequency of 382.5 MHz showed a strong, positive and significant correlation with r = 0.555, while small and medium for others. This finding is useful to a radio astronomer to help determine the best period for radio astronomy observation with the lowest interference considering the weather in the East Coast of Peninsular Malaysia. Besides, this finding benefits a spectrum of users involved in mobile telecommunication, wireless internet, radio TV transmission and satellite broadcasting.

Keywords: Correlation; radio signal attenuation; radio signal strength; wind speed

ABSTRAK

Pantai Timur Semenanjung Malaysia menerima kelajuan angin yang kuat, hujan lebat dan kelembapan yang tinggi semasa monsun Timur Laut. Jabatan Meteorologi Malaysia menyatakan bahawa kelajuan angin semasa musim Timur Laut boleh mencapai 55.56 km/jam atau lebih. Kelajuan angin yang kuat dan hujan lebat ini menyumbang kepada pengurangan isyarat radio. Dalam kajian ini, kami mengkaji hubungan antara kelajuan angin (km/jam) dan kekuatan isyarat radio, RSS (dBm). Korelasi statistik digunakan untuk mengenal pasti nilai korelasi dan kekuatan antara kedua-dua faktor itu. Kelajuan angin dan RSS direkodkan pada musim lembab dan kering di Kusza Observatori sementara penganalisis spektrum digunakan untuk pengukuran RSS (dBm) dan alat stesen cuaca untuk kelajuan angin (km/jam). Keputusan kajian musim lembab menunjukkan korelasi yang kuat dan ketara berbanding musim kering. Frekuensi 382.5 MHz, 945 MHz dan 2160 MHz menunjukkan korelasi yang kuat negatif dan signifikan dengan kelajuan angin dan nilai korelasi r = -0.583; -0.631 dan -0: 514 pada musim lembab. Untuk musim kering, hanya frekuensi 382.5 MHz menunjukkan korelasi yang positif dan signifikan dengan r = 0.555, manakala korelasi kecil dan sederhana untuk yang lain. Penemuan ini berguna kepada astronomi radio untuk menentukan tempoh terbaik dalam kajian astronomi radio dengan gangguan yang paling rendah dengan cara mempertimbangkan faktor cuaca di pantai timur Semenanjung Malaysia. Di samping itu, penemuan ini akan memberi manfaat kepada pengguna spektrum seperti telekomunikasi mudah alih, internet tanpa wayar, transmisi TV radio dan penyiaran satelit.

Kata kunci: Kekuatan isyarat radio; kelajuan angin; korelasi; pengurangan isyarat radio

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*Pengarang untuk surat-menyurat; email: norhazmin@umt.edu.my