 Hi, I'm Thomas with RF Elements, and today's episode is about noise lore. Noise is the signal that RF radio receives but doesn't understand. Noise lore tells us how strong the noise is and determines the signal to noise ratio, which tells us how strong the useful signal is compared to the noise. There are two main sources of noise. First, is the noise created by the radio itself because of the physics of the parts it is built from. There are many types of noise devices produced, such as thermal noise, flicker noise, shot noise or burst noise. Some of all these types of noise makes up the noise floor created by the radio itself. In the lab conditions, the noise floor is the jittery line at the bottom of the spectrum the radio works with. The useful signal is recognized by clearly higher level above the noise floor. Second type of noise is man-made. The devices located near your radio produce signals seen as noise by your radio and are received through the antenna. The man-made interference is usually much stronger than the noise created by the radio itself and is the biggest problem of fixed wireless networks. Your radio sees the signal quality primarily through the SNR given that the signal is between the noise floor and the maximum powered radio can work with. Interference decreases the SNR your radio is working with. Lower SNR means lower MCS rates seen as decreased overall throughput at the user end. A frequent misunderstanding among wisps is that the solution to the interference is to use the antenna with higher gain. Although higher gain antenna will increase the received signal strength, it can be harmful to the SNR because of the side lobes which decide how much added noise your radio sees. The traditional sector patch array antennas have huge side lobes, so the benefit of added signal due to the higher gain can be drowned in the added noise caused by the side lobes in high noise areas. The best way to avoid increasing the noise floor is to avoid collecting their interference in the first place. Using an antenna with small or no side lobes such as horn will push the noise floor down. Despite the horn might have smaller gain, the Leica side lobes improves the SNR, so eventually the link can perform better than with a higher gain antenna. If you want to know more about link planning, stay tuned for some of our following episodes.