Suherman, S., Hanafiah Rambe, A. and Widodo Tanjung, A. (2018) “Underground Radio Propagation on Frequency Band 97 Mhz – 130 Mhz”, International Journal of Engineering & Technology, 7(3.2), pp. 722–726. doi:10.14419/ijet.v7i3.2.15352.