The video signal of the TV is in the AM format! The audio signal is in the FM format! If the signal input of the machine is closed, it is difficult to interfere! If the antenna is open, it is easy to interfere! device can interfere!

Ground satellite signal jammers can be divided into digital TV image signal interference and carrier (or narrowband) signal interference from the interference means. The former is to use illegal image interference, that is, to use the same digital form as the normal broadcast signal to make the normal image appear mosaic or black. The interference is mainly based on power occupation, that is, transmitting high-power and co-frequency signals in the same direction, and implementing power occupation for the satellite receiving channel within a certain frequency range, so that the field strength of the interference signal is far greater than the signal field strength of the normal satellite reaching the ground, and the interference is achieved. The purpose of suppressing satellite signal reception. The latter is divided into co-channel interference and non-co-channel interference; for co-channel interference, the interference signal can cause serious mosaic or pause in the image, and a black screen will appear when the interference is serious. For non-co-channel interference, due to the frequency selection effect of the satellite receiver, the interference level is allowed to be greater than the signal level, but if the interference level is so large that the tuner enters a saturated state, the TV screen will appear black at this time. However, satellite signal jammers are limited by distance and azimuth, because the transmitted interference microwave propagation loss is related to the operating frequency and propagation distance, so under free space propagation conditions, the farther the distance, the worse the ability to interfere. For 3.7GHz ~ 4.2GHz satellite signal interference system transmission distance is generally not more than 3km.