## 2 Materials and Methods: Description of the Measurement Setup
### Description of the INAF Mobile Laboratory  
The INAF mobile laboratory allows measurements over a wide frequency band, ranging from 250 MHz to 40 GHz [19]. It is equipped with a retractable telescopic mast on which the antenna is mounted. The antenna can be rotated manually or electronically in the azimuthal direction via a motor. A second motor at the top of the mast allows for the rotation of the antenna to select either horizontal or vertical polarization. Concerning the front end, the INAF mobile laboratory is equipped with six different radio frequency paths (i.e., channels) for operations up to 18 GHz, as well as an additional configuration for measurements from 18 GHz to 40 GHz [19]. A block diagram of the front end, operating up to 18 GHz, is shown in Figure 2. Each path is composed of commercial microwave components optimized for a specific frequency range, for which an appropriate antenna can be chosen from the five available. A detailed description of the entire front end, including the total characterization of each microwave component and antenna model,  
Figure 1: Map of the selected points for the RFI measurement campaign. is provided in [20]. In particular, channels D and E, highlighted in red in Figure 2, are used for the C-band measurements presented in this paper. For the measurements presented in this work, a dual-ridge horn antenna, model DRG-118-A from A.R.A. Technologies (Laurel, MD, USA) [21], was used. The antenna has an average gain of 11.6 dBi and an average antenna factor of 36.6 dB/m within the frequency range of 1-18 GHz. Analyzing Figure 2, the antenna is connected via a coaxial cable to a waterproof metallic box housing the microwave components of the front end. The first component of this box is a six-channel microwave switch, model RLC SR-6C-H from RLC Electronics (Mount Kisco, NY, USA) [22], which has an insertion loss of approximately 0.3 dB and channel isolation of approximately 60 dB in the C-band. A microwave filter is directly connected to the switch. Specifically, for channel D, a band-pass cavity filter, model SIZ5-4400/R2200-S from Lorch (Cedar Hill, TX, USA) [23], with an insertion loss of less than 1 dB in the 3.3 GHz to 5.5 GHz range, is used. For channel E, a band-pass cavity filter, model SIZ6-7200/R3600-S from Lorch [23], with an insertion loss of less than 1 dB in the 5.4 GHz to 9 GHz range, is employed. For each of the two channels, the filter is connected in series with a low-pass filter, which ensures the suppression of frequencies above the cutoff. Another switch, a seven-channel microwave switch, model RLC SR-7C-H from RLC Electronics [22], with similar characteristics to the input switch described above, is installed for ending the multiple channel selection. This output switch is connected via a coaxial cable to an amplifier, model AMF-6D-00101800-35-20P from Miteq (Hauppauge, NY, USA) [24], which has an average gain of approximately 42 dB, an output 1 dB compression point of +20 dBm, and a noise figure of 3.5 dB over the frequency range from 100 MHz to 18 GHz. In addition to these radio frequency components, an electronic board for powering the active devices is installed inside the metallic box. The front end is connected via a coaxial cable to an external spiral coaxial cable, approximately 17 m in length, which wraps around the retractable telescopic mast of the mobile laboratory and facilitates the connection with the laboratory's back end. This spiral cable has a loss of approximately \(-15\) dB at 5 GHz. A summary of the technical specifications (i.e., frequency range and average gain at 5 GHz) for each component of the receiving chain is reported in Table 1.  
Figure 2: The front end of the INAF mobile laboratory is composed of six radio frequency channels, covering the entire frequency range from 250 MHz to 40 GHz. The channels highlighted in red (i.e., channels D and E) were used for the measurement campaign presented in this paper.