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The radio acoustic sounding system (RASS) with the equatorial atmosphere radar (EAR) at Koto Tabang, Indonesia was adapted to test the effects of the acoustic source location and acoustic frequency range on the continuous measurement of height profiles of temperature in the tropical troposphere. We installed the acoustic transmitting system by using six high-power horn speakers and four subwoofers. We developed a three-dimensional ray-tracing method of acoustic waves to predict the shape of acoustic wavefronts, accounting for the effects of the background winds on acoustic wave propagation. Then, we selected the appropriate antenna beam directions for EAR that satisfy the Bragg condition between the radar and acoustic wave propagation vectors. We carried out eight campaign observations in 2016, testing the performance of EAR–RASS. We found that the location and acoustic frequency range affected the RASS echoes. We also tested the compensation method of the background wind velocity with EAR to obtain the true sound speed. We intensively analyzed the RASS results from August 29 to September 3, 2016, when radiosondes were launched 12 times from the EAR site. We successfully retrieved the temperature profiles from RASS from 2 to 6–14 km with time and height resolutions of about 10 min and 150 m, respectively. Some temperature profiles were obtained up to about the tropopause at 17 km, although the observation period was short. During the RASS campaign, we detected a few interesting events regarding temperature variations as well as large perturbations in the three components of wind velocity.

Radar has been widely used for various purposes such as monitoring atmospheric precipitation. For that purpose, it gives more accurate results than satellites do. Previous research has developed navigation radar that alters its functions into an atmospheric precipitation monitoring radar. To improve the development of the radar, an antenna system will be developed in this research. The purpose of developing this antenna is to obtain better data reception results. This antenna is a microstrip rectangular array antenna that works on X-band with a frequency of 9.41 GHz. Microstrip antenna is chosen since it has several advantages such as small dimensions and relatively low costs. The designed antenna gain ≥ 12 dB, bandwidth of 60 MHz, and horizontal polarization. Antenna fabrication produces a microstrip rectangular 16 x 1 array antenna using the mitered bend method at a frequency of 9.4 GHz with a reflection coefficient of -22.8 dB, VSWR of 1.2, gain of 13.21 dB, unidirectional radiation patterns and horizontal polarization.