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 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.