Recently, Unmanned Aerial Vehicle (UAV) becomes a popular and interesting technology for researchers and academics because it has high potential to be implemented in various fields. The UAV operation is managed by a Ground Control Station (GCS) on which requires a communication system to send control signals and acquire data collected by sensors on UAV. The longer the UAV's flying distance needs a higher transmission power budget that can be achieved by increasing transmitter power, increasing receiver sensitivity, or increasing antenna gain. However, the design of communications systems on a flying platform is limited by the following constraints. The transmitter, receiver, and antenna must be compact, lightweight, and energy-efficient to save battery on the vehicle. Although the antenna does not directly influence the energy consumption from the battery, an increase in antenna gain usually requires an increase of the antenna dimension that causes higher weight and or reduces the aerodynamics. Therefore, the most efficient way to increase the link budget is by modifying the antenna on the GCS. This paper describes the analysis of antennas commonly used in GCSs for UAV communication links, namely the Yagi-Uda, bi-quad, and double bi-quad antennas. The antenna is designed to work at a frequency of 433.5 MHz following the transceiver device used. The antenna designs are numerically simulated then fabricated for evaluating their performance. The testing is done on the following issues, i.e. the antenna's basic parameters measurement, the ground-to-ground transmission test, and the ground to air transmission test. The test results show that the double bi-quad gives better performance than the other two other testing antennas.

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Visible light communication (VLC) is a communication technology using visible light as a transmission medium that can have larger bandwidth than other wireless communications. VLC has a standard of IEEE 802.15.7 which has two layers. One of the layers is Physical Layer (PHY) II which has characterictic for indoor and line of sight communication. In this layer, the standard for data rate and optical clock rate is higher than the other types of layers using on off keying (OOK) modulation. This research investigated variation effect of clock rate, data rate, and Reed Solomon (RS) coding to bit error rate (BER) of the received signal. Nowadays, mostly data are pictures and videos. So, this research also test the VLC PHY II to transmit a picture under the varied conditions using peak signal to noise ratio (PSNR). All investigations are built in simulation. The results show that the lower RS coding rates, the lower BER values, and the higher optical clock rate, the higher data rate obtained. Good quality of picture is obtained with BER 10-4 and PSNR 39 dB. Intisari-Komunikasi cahaya tampak atau visible light communication (VLC) merupakan komunikasi dengan menggunakan gelombang cahaya tampak sebagai media transmisinya. VLC memiliki standar IEEE 802.15.7 yang mendefinisikan dua lapisan, salah satunya lapisan fisik atau Physical layer (PHY). Lapisan PHY ini ada tiga jenis dan di antaranya merupakan standar lapisan untuk indoor dan line of sight (LOS), yaitu lapisan PHY II. Pada lapisan ini, standar untuk pesat data dan optical clock rate yang tinggi menggunakan modulasi on off keying (OOK). Dengan asumsi derau yang ada hanya shot noise yang bersifat AWGN, makalah ini menguji unjuk kerja PHY II modulasi OOK untuk pesat data, optical clock rate, dan jenis penyandian kanal Reed Solomon (RS) yang bervariasi dengan melihat nilai bit error rate (BER) yang dihasilkan. Selain itu, tren pengiriman informasi saat ini lebih banyak berupa pengiriman video atau citra. Karena itu, pada PHY II modulasi OOK ini juga diuji untuk pengiriman citra atau citra yang kualitas citra diukur dengan nilai peak signal to noise ratio (PSNR). Penelitian dalam makalah ini menggunakan MATLAB sebagai alat simulasinya. Hasil menunjukkan bahwa coding rate RS yang lebih kecil mengakibatkan BER yang lebih kecil. Optical clock rate yang lebih tinggi menjadikan pesat data yang lebih tinggi pula. Kualitas citra yang baik diperoleh dengan BER 10-4 dan PSNR 39 dB.