Anritsu Company: RF Interference Hunting Techniques

As wireless technology grows at a rapid rate, there is a potential for interference to occur for wireless and broadcast services. Anritsu Company shared an article about how to spot interference and the first indicators of interference. The company explained, “The first indicators of interference are noisy links, for analog systems. Legacy AM and FM systems indicate interference problems by various noises. Hiss, hum, or even voices from other transmissions can be heard. For digital transmissions, such as HDTV, cellular, or P25, interference shows up as limited range, dropped calls, or low data rate. That familiar waterfall sound on your cellular phone indicates poor reception and a high bit error rate, which might be caused by interference. A second indicator of interference is a high noise floor in the receive channel. Interference naturally affects reception first, where the signal levels are normally small. Some radio systems, cellular systems in particular, monitor the receive noise floor level specifically to detect poor reception conditions. Broadcasters, who don’t receive, rely on customer complaints and field measurements instead. A high receive noise floor is the diagnostic for interference. This warrants an interference hunt and identifies the geographic starting point.” Interference is a receive issue. This means that you need to be looking for interference on receive frequencies. If you are working a cellular issue, and the base station has a high noise floor, you need to be looking on the uplink channels, not the downlink. If the issue is, instead, cell phone reception in a given area, then you would look on the downlink frequencies, since that is what the cellphone receives. (Source: Anritsu Company)