Analysis of Path Loss and Delay in Tsunami Early Warning Siren Based on DTMF Signals via VHF Frequency

Indonesia, located in the seismically active Ring of Fire, faces a significant risk of tsunamis due to its geological characteristics. Effective disaster preparedness and mitigation strategies are crucial to minimize the impact of tsunamis. This research aims to design and test a DTMF-based tsunami early warning siren system, which utilizes Dual-Tone Multi- Frequency signals via VHF frequencies to remotely control sirens. A security code is built into the system to keep out interference and guarantee consistent communication. Three distinct locations-rural, suburban, and urban-were used for the research. According to the results, the system works best in suburban areas at a height of 147 meters, where the delay is most stable (between 2.49 and 3.43 seconds) and the path loss is lowest (between 60.6 dB and 88.3 dB). On the other hand, because of increased path loss and uncertain delay, the system performs poorer in urban and rural locations. The study indicates that line-of-sight connection between the radio transmitter and receiver antennas is crucial to ensuring steady signal strength and that the DTMF-based siren system is a workable alternative for tsunami early warning systems in Indonesia, particularly in suburban areas.