Living under satellite dishes and yagi antennas fixed to a roof does not pose a significant health risk due to radiation exposure. The antennas used for satellite reception, including the Low Noise Block (LNB) fixed to satellite dishes, are designed to receive signals from satellites in space and do not emit harmful radiation.
The LNB in a satellite dish is a small component responsible for receiving the weak signals from satellites and amplifying them for the receiver inside your home. The amplification occurs at a very low power level, and the signals are focused on the dish's parabolic reflector to maximize reception efficiency. The LNB itself does not emit or generate microwave radiation; it merely receives and amplifies existing signals.
The signals that come from outer space are extremely weak and not harmful. The microwaves from satellites are at very low power levels and are not the same as the microwave radiation used in microwave ovens for cooking. The microwave radiation from satellite signals is at much lower power levels and not harmful to human health.
Regarding Yagi antennas, they are typically used for TV or radio reception, and they, too, do not emit harmful radiation. Yagi antennas are passive devices that only receive signals; they don't generate any significant radiation on their own.
In summary, the antennas used for satellite and TV/radio reception, such as satellite dishes and Yagi antennas, are designed to be safe and do not emit harmful levels of radiation. The signals they receive are extremely weak and pose no danger to human health. However, as with any electronic equipment, it's essential to ensure that the installation is done correctly, and the equipment is well-maintained to avoid any structural or safety issues. If you have concerns about the installation or safety of antennas on your roof, it's a good idea to consult a professional to assess the situation.