Analysis of Radio Noise in a Mountain Radio Observation Station

Radio noise at mountainous observatories affects the deployment of radio observation equipment. Existing mountainous-station measurements have mainly focused on spectrum occupancy and interference amplitude, while the statistical properties of the noise remain insufficiently addressed. To fill this gap, this study analyzes both the Gaussian and impulsive components of the noise. Radio noise in the 30–500 MHz band was measured at a high-altitude mountainous station in southwestern China using a USRP X310 software-defined radio. For the Gaussian component, the measured noise figure exceeds the ITU-R P.372-17 model and decreases with frequency. A smoothing spline model achieved an RMSE of 0.8687, an MAE of 0.3843, and an R2 of 0.9929, outperforming the ITU-R P.372-17 model. For the impulsive component, pulse events were concentrated in the 30–140 MHz and 200–270 MHz bands. An XGBoost regression model was trained to predict IN level density and pulse length from statistical features and was benchmarked against linear, polynomial, and random forest baselines under leave-one-time-block-out cross-validation. These results provide empirical data and references for radio service deployment at mountainous observation stations.