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At this time the research related to the effect of magnetostriction for underwater applications is still limited. Acoustic or sound waves are more easily propagated underwater than electromagnetic waves or light. An acoustic wave or sound can be generated by utilizing the magnetostriction effect, where this effect occurs when a rod of ferromagnetic material such as iron or nickel is magnetized and interacts with another magnetic field, resulting in vibration of the metal rod. This research aims to design and realize a magnetostriction generator as an acoustic wave generator at a frequency of 1 to 10 kHz for underwater applications, consisting of: a tuned LC oscillator circuit, and a ferromagnetic metal rod which is magnetized using a dc voltage. The results of measurements and testing of the magnetostriction generator show: (1) if it is equipped with a membrane, can work to emit an acoustic wave or sound at a frequency of ± 8.62 kHz in the air up to a distance of 15 cm without distortion with an average amplitude decrease of ± 0.648 dB for each the distance increased by 1 cm, and (2) if equipped with a membrane and enclosed in a waterproof casing, capable of transmitting the acoustic waves at a frequency of ± 8.31 kHz underwater up to a distance of 7 cm without distortion with an average amplitude decrease of ± 4.217 dB for each the distance up 1 cm. Overall the magnetostriction generator designed can work to generate and transmit the acoustic waves or sound underwater, as expected.

To find out the location of an aircraft accident from an ELT signal beam of 121.5 MHz, search and rescue (SAR) officers or civil aviation authorities need an ELT signal receiver device that works at the same frequency, which is 121.5 MHz. The purpose of this research is to produce an ELT signal receiver with direct receiver method at a frequency of 121.5 MHz which is simpler, requires fewer RF devices, and is according to specifications for civil aviation. In this research, the design and realization of ELT signal receivers are carried out using the direct receiver method, including: a BPF and a RF amplifier as a direct receiver circuit, an AM demodulator, and an audio amplifier. Based on the results of measurements and tests that have been done, the direct receiver circuit can receive an ELT signal at a frequency of 121.5 MHz in the range of 121.330 to 121.617 MHz with -40.35 dB sensitivity, the AM demodulator can demodulate the audio signal at a frequency of 346.6 Hz, and the audio signal at a frequency of 337.6 Hz as a pointer to an ELT signal can be heard through the loudspeaker. The results of this study are ELT signal receivers with direct receiver method at a frequency of 121.5 MHz which are according to specifications for civil aviation.

A Radio detection and ranging (radar) is used to detect and track objects in the air and on land, one type of the radar that is known is a passive radar. The radio direction finder (RDF) as an element of a passive radar is used to determine the direction angle, based on a radio waves that emitted by an object. The purpose of this study is to produce a RDF that works on HF bands as passive radar elements. In this study a RDF has been produced, which consists: a receive antenna in the form of a dipole λ/8 and a yagi 5 elements with horizontal polarization, a tuning circuit, an AM signal detector, an audio amplifier, and equipped with a level signal display in the form of a S meter and a loudspeaker. The test results for outside and inside the room at a certain time, the RDF can detect the angle of direction of horizontal plane of an object or AM transmitter from 0° to 360° in the frequency range between 4.02 to 10.76 MHz. The results of detecting the angle of direction of an object or a transmitting radio waves in the HF band, in the form of a signal level are then plotted on the polar diagram of the horizontal plane, and the sound can be heard through the loudspeaker. Furthermore, the results of this study can be used for the development of a RDF independently, and its implementation in the passive radar.

An ELT is a beacon indicating the location of distress or crash of aircraft on land or sea. The ELT is placed in an airplane, which is a transmitter with low transmit power and an antenna. The ELT transmitter has been widely used for flights at the frequency of 121.5 MHz (civilian) and 243 MHz (military). The purpose of this study is to produce ELT signal generators at the 121.5 MHz frequency, with low-cost devices that meet specifications for civil aviation. In this research has been produced a design of an ELT signal generator at the frequency of 121.5 MHz, consist of a crystal oscillator, a sawtooth generator, a VCO, and an amplitude modulator. Based on the measurement and test results, the sawtooth generator generated a sawtooth signal at the frequency of 1.8 to 3.6 Hz, the VCO generated a sinusoidal signal at the frequency of 316 to 366 Hz, the RF generator generated a sinusoidal at the frequency of 121.505 MHz. The ELT signal generator was able to generate AM signals at the minimum amplitude deviation of 100 mVpp to maximum one of 156 mVpp, the modulation index (m) of 21.875%, and the frequency of 121.505 MHz. The results of this study are ELT signal generators at the frequencies of 121.5 MHz that are in accordance with specifications for civil aviation.

Black box yang terdiri cockpit voice recorder dan flight data recorder dapat dideteksi lokasinya karena dilengkapi dengan beacon black box locator acoustic 37,5 kHz atau pinger yang memancarkan sinyal akustik 37,5 kHz. Untuk mendeteksi sinyal pinger yang mempunyai frekuensi 37,5 kHz, digunakan detektor sinyal pinger, yang mampu mendeteksi gelombang ultrasonic di dalam air pada frekuensi 37,5 1 kHz. Makalah ini membahas perancangan pembangkit dan detektor sinyal pinger 37,5 kHz. Rancangan pembangkit sinyal pinger untuk membangkitkan sinyal pinger dengan frekuensi keluaran 37,5 1 kHz, terdiri rangkaian osilator, pulse generator, pulse inverter, modulator OOK, dan audio amplifier. Rancangan detektor sinyal pinger untuk mendeteksi sinyal pinger dengan frekuensi 37,5 1 kHz, terdiri rangkaian band pass filter, demodulator OOK, audio amplifier, dan loudspeaker. Berdasarkan hasil pengujian, pembangkit sinyal pinger mampu membangkitkan sinyal pinger dengan amplitudo 12,2 Vp-p, frekuensi 37,69 kHz, lebar pulsa (kondisi on sebesar 9,8 ms), dan PRF sebesar 1 s sedangkan detektor sinyal pinger mampu mendeteksi sinyal pinger 37,5 kHz dan menghasilkan keluaran berupa pulsa dengan amplitudo 9 Vp-p, lebar pulsa 14 ms, dan PRF sebesar 1 s, serta suara yang dihasilkan terdengar jelas setiap interval 1 s.

ABSTRAK Dalam pencarian suatu obyek di bawah air dibutuhkan metode khusus yang digunakan dengan suara (gelombang akustik), dikarenakan suara dapat merambat dalam jarak jauh pada air. Frekuensi yang dapat diterima oleh SONAR bergantung pada alat penerima yang mengubah suara menjadi sinyal elektrik agar dapat mendeteksi frekuensi, alat penerima ini dinamakan hydrophone. Dalam penelitian ini dibuat perancangan prototipe hydrophone, yang tersusun dari transducer (akustik-elektrik) dan penguat. Berdasarkan perancangan yang telah dibuat prototipe hydrophone mampu menerima (menangkap) gelombang akustik pada range frekuensi 100 Hz – 60 kHz, dengan menggunakan transducer berupa condenser microphone yang diselimuti oleh bahan karet tipis. Prototipe hydrophone tanpa pelindung anti air, dengan pelindung anti air, dan di dalam air dapat menerima (menangkap) gelombang akustik. Kata Kunci: SONAR, hydrophone, transducer ABSTRACT In finding an object beneath the water there has to be a specific method used sound (accoustic wave) in keeping with it can apread in long distance in the depth of water. The frequency which can be detected by sonar system, counts on the receiver which converts sound to electric signal so that the frequency can be detected and it is called hydrophone. In this research, there is hydrophone prototype which piled up by tranducer and amplifier. Based on the trial, hydrophone prototype can detect accoustic wave in range 100 Hz-60 kHz with the condensor microphone as a transducer covered of thin rubber material. Besides, hydrophone prototype with or without water resistor is still capable to detect acoustic wave. Keywords: SONAR, hydrophone, transducer

ABSTRAK Pingers transmitter berfungsi untuk memancarkan sinyal atau getaran pulsa akustik pada black box. Frekuensi sinyal yang dipancarkan sebesar 37,5 kHz yang dimodulasikan oleh pulsa dengan durasi 10 ms setiap interval 1 second. Modulasi yang digunakan adalah modulasi on off keying. Dalam penelitian ini dibuat perancangan pingers transmitter yang tersusun atas rangkaian osilator, timer, inverter, switch dan rangkaian amplifier. Frekuensi 37,5 kHz tersebut dibangkitkan oleh rangkaian osilator colpitts, sedangkan lebar pulsa dengan durasi 10 ms dan pengulangan pulsa setiap interval 1 second dibangkitkan oleh rangkaian timer. Berdasarkan perancangan yang telah dibuat, output sinyal yang dihasilkan oleh prototipe pingers transmitter tersebut sebesar 37,69 kHz dengan lebar pulsa 9,8 ms setiap interval 1 second. Kata kunci: Black box, pingers transmitter, on off keying. ABSTRACT Pingers transmitter is used to emits a signal or pulse of acoustic vibrations in black box. The frequency of the transmitted signal is 37.5 kHz which is modulated by pulses with a duration of 10 ms every interval 1 second. The modulation that used this research is on off keying modulation. In this research, made the design of pingers transmitter which arrange of the oscillator circuit,timer, inverter, switch, and amplifier circuit. The 37.5 kHz frequency is generated by the colpitts oscillator circuit, while the pulse width with a duration of 10 ms,and each pulse repetition interval of 1 second generated by timer circuit. Based on the design that have made, signal output from the pingers transmitter prototype is 37.69 kHz, with the pulse width 9.8 ms every 1 second interval. Keywords: Black box, pingers transmitter, on off keying.

ABSTRAK Keandalan tenaga listrik didefinisikan sebagai peluang dari suatu peralatan untuk beroperasi sesuai dengan fungsinya dalam suatu selang waktu tertentu dan dalam suatu kondisi operasi tertentu, sehingga dapat memenuhi kebutuhan listrik konsumen. Keandalan ketersediaan daya suatu sistem pembangkit dapat diketahui berdasarkan indeks keandalan yaitu LOLP (Loss of Load Probability) dan UE (Unserved Energy). Penelitian dilakukan dengan merancang 2 model konfigurasi sistem pembangkit berdasarkan nilai beban puncak, kemudian mengambil data laju kegagalan dan laju perbaikan dari masing-masing komponen sistem pembangkit yang selanjutnya dipakai untuk menghitung nilai FOR (Forced Outage Rate). Nilai FOR yang telah diperoleh digunakan untuk menghitung nilai indeks keandalan menggunakan metode segmentasi. Konfigurasi sistem pembangkit skenario ke-2 memiliki nilai indeks keandalan lebih kecil dibandingkan dengan konfigurasi sistem pembangkit skenario ke-1 yaitu dengan LOLP sebesar 0,0000088248 hari/tahun dan UE sebesar 0,0584 KWH/tahun dengan total perkiraan biaya pada konfigurasi ini sebesar Rp 587.567.108,00. Kata kunci: Keandalan, metode segmentasi, LOLP, FOR, UE ABSTRACT The reliability of electric power is defined as the chance of an apparatus to operate in accordance with its function in a certain interval of time and in a certain operating conditions, so as to meet the electricity needs of consumers. The reliability of a power generation system availability can be determined based on the reliability index is LOLP (Loss of Load Probability) and UE (Unserved Energy). The study was conducted by designing two models generating system configuration based on the value of the peak load, and then retrieve the data failure rate and the rate of repair of the individual components of the next generation system which is used to calculate the value FOR (Forced Outage Rate). FOR Value that has been obtained is used to calculate the reliability index using segmentation method. Generating system configuration scenarios to-2 has a reliability index value is smaller than the generating system configuration scenarios to-1 that is by LOLP of 0.0000088248 days / year and the EU amounted to 0.0584 KWH / year with a total estimated cost in this configuration Rp 587,567,108.00. Keywords: Reliability, segmentation method, LOLP, FOR, UE