Measuring and Monitoring Satellite Signals

Measuring and monitoring the signals in satellite communications systems is as complex as the tasks of those involved in operating such systems. Satellite operators are normally interested in ensuring that transponder use corresponds to the criteria agreed with users in terms of quality and scope, which also includes the detection of any interference signals. Teleport operators are concerned with making the best possible use of the resources with the communications systems, particularly the space segment. This involves monitoring the transmitted signals, which includes checking the spectrum for unwanted intermodulation products in the case of multi-carrier operation. It is also necessary in stations with uplink power control to ascertain atmospheric attenuation effects in real time if possible to use as input values for the power settings. The power levels of the individual signals radiated by the satellite can also be determined at the teleport. SNG operators need assistance during line-up for aligning the antenna and during operation for monitoring the transmitted signals. It is also useful to evaluate the received signals in order to identify impairments in the transmission path caused by obstacles, for example. This Application Note describes example measurement principles that cover the above-mentioned applications and for which the NRA range of spectrum analyzers from Narda is particularly suitable.