A device that can send text messages in groups within a few kilometers.

2 to 4 kilometers. Pseudo base stations still radiate a lot to human body, and there is no specific data to compare, only analogy. The coverage of a pseudo base station is usually much smaller than that of an ordinary base station. In Fiona Fang, where there is no terrain obstacle, its working range is about 5 kilometers, and its power is about one tenth of that of an ordinary base station. However, considering the distance factor, the radiation amount is about 100 times that of ordinary mobile phones, which will still have an impact on human health.