## 3 Results and Discussion
Finally, a summary chart of the entire band occupancy, including both detected continuous and impulsive signals, is shown in Figure 5. This chart is crucial for astronomers using the SRT, as it provides a reference for the band occupancy of the C-low receiver by signals from the telescope's surrounding environment, which can be detected with every pointing direction of the telescope. Figure 4: Results of wideband campaign, with the RBW of the spectrum analyzer set to 3 MHz, conducted in October–November 2023 in area number 1, area number 2 and area number 3. Figure 3: Results of narrowband campaign, with the RBW of the spectrum analyzer set to 300 kHz, conducted in October–November 2023 in area number 1, area number 2 and area number 3. For a more detailed analysis of the RFI scenario, Figure 6 presents a graph that distinguishes between signals detected with the antenna polarized horizontally and vertically. It is noteworthy that except for the signals in the frequency range of 4.03-4.08 GHz, which were detected only during measurements with horizontal polarization, all other signals were detected with both antenna polarizations. This differentiation of RFI polarization can be useful for astronomers when planning scientific observations with the SRT. For informational purposes, an analysis of the state of the art reveals that the signals detected during this measurement campaign can be traced back to satellite communications, including full-time satellite TV networks or raw satellite feeds [27; 28; 29], as well as to terrestrial wireless broadband systems used for both civil and military communications [30] and several radar applications [31]. Based on the results in Figure 5, scientific observations can be optimized by implementing various RFI mitigation techniques, such as using software to remove unwanted signals or shifting to an interference-free frequency range by appropriately adjusting the local oscillator. Indeed, the SRT operates as a super heterodyne system, with most of its  
Figure 5: Summary chart of the entire RFI scenario in the frequency range from 4 to 5.8 GHz around the Sardinia Radio Telescope (SRT). This chart includes all signals detected during both the narrowband and wideband campaigns, conducted in October–November 2023. Figure 6: Polarization characteristics of detected signals during both the wideband and narrowband campaigns, conducted in October–November 2023.  
receivers featuring a frequency down-conversion system that shifts the detected signals from the sky to a baseband frequency range of 100 MHz to 2.1 GHz. For the C-low receiver (a detailed description of the system is provided in [16]), which covers a bandwidth from 4.2 GHz to 5.6 GHz, a filter at an intermediate frequency (for example, from 100 MHz to 400 MHz) within the telescope's receiving chain can be used to isolate a specific portion of the receiver's bandwidth. By adjusting the local oscillator frequency of the receiver, directly settable from the SRT control system, it is possible to select the desired free-of-RFI bandwidth segment from 4.37 to 4.95 GHz that will coincide to the actual bandwidth of the filter at the intermediate frequency. The results presented in this article could be refined by scheduling a new measurement campaign using both the telescope directly and the mobile laboratory. This would involve conducting scans in all azimuthal directions while varying the elevation angle to determine the exact direction of the source relative to the telescope's position. Such an approach could allow for the creation of a detailed three-dimensional map of the sources generating RFI. Consequently, it would help identify the telescope's pointing directions that would lead to receiving the strongest signals. This type of work could be valuable for filtering out unwanted signals during survey-mode observations, which involve continuous scanning of the sky for radio astronomical sources.