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    A study on Ka-band site switching using advanced prediction for rain-induced attenuation
    (2015-01-28)
    Poolsawut, Jirutchaya
    ;
    Limpiti, Tulaya
    ;
    Puttarak, Nattakan
    High frequency satellite communications suffers from rain-induced attenuations, which may cause service discontinuity during high-intensity rain events. To combat this, we propose a novel site switching technique that anticipates signal attenuations using a linear dynamical system response model and performs site switching in advance. Using only the rainfall data measured at a ground station for attenuation prediction, we demonstrate that our method is able to lessen signal attenuation while maintaining link availability.
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    System control design via AC line for security system
    (2005-12-01)
    Kirdpipat, Putthiphong
    ;
    Mitatha, Somsak
    ;
    Thipchaksurat, Sakchai
    In this paper, we present the system control design via AC line for the security system. The system comprises houses and control node such as center control, node control and home control which are connected as the two levels network called master-slave model. Our system can support the data rate up to 9,600 bits per second with the maximum distance at 1,200 meters. The transmission data are encrypted using DES algorithm. Moreover, the system can connect to the Internet by using web service protocol and only one IP address is needed for our system. The measurement of electricity can be done automatically. We design the protocol for controlling all the electric equipments via AC line with FSK modulation technique, which can support the data rate up to 250 bits per second with the distance at 300 meters. We evaluate the performance of our system by means of experiment. The results showed that we can achieve 99.99 and 99.92 percents for the transmission without error on the network and AC line, respectively. We also examine the signal attenuation depends on the number of load, load type and position of load between transmitter and receiver. © 2005 IEEE.
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    Ka-band rain attenuation by radiometer method
    (2003-01-01)
    Nukfron, E.
    ;
    Boonchank, T.
    ;
    Decharat, A.
    ;
    Hemmakorn, N.
    This paper would focus on investigating signal attenuation of Ka-band at zone N by using radiometer method and finally analyses the collective data by new developing indirect equation is ratiometer equation. According to equation analysis, the signal attenuation of Ka-band frequency depends on the differentiation of noise signal between clear sky condition and rain condition. Consequently, increasing of noise signal level is the result from rain cloud absorbing and discharging. The experiment site in this article was located at King Mongkut's Institute of Technology (KMITL) LadKrabang, Bangkok, Thailand (latitude 108E° and longitude 13.7N°) which represent for the tropical zone site. During 12 months of experiment period from May 2001 to April 2002, the results reveals clearly that the signal attenuation of Ka-band frequency are divided into 3 stages as follow: Stage I: signal attenuation before raining which is affect from rain cloud; Stage II: signal attenuation in raining period which is affect from rain; Stage III: signal attenuation after raining which is affect from high humidity. Finally, this paper will present worst month and lowest month in cumulative attenuation.