Is Liujiaxia in Lanzhou, Gansu a place where there is no signal?

Liujiaxia in Lanzhou, Gansu Province is a place where there is no signal. According to relevant information, there is no road between Lanzhou and Liujiaxia, and it takes 40 minutes to get out of the blind area. Liujiaxia Reservoir is located in the upper reaches of the Yellow River, southwest of Yongjing County, Linxia City, Gansu Province 1 km, 75 km away from Lanzhou City. It is a large-scale hydropower project designed, constructed and built in China during the first five-year plan period, and was completed in 1974.