Testing and integration of the S-Band chain on the Cubesat Control Centre

With the constant demand for higher data rates to accommodate increasingly sophisticated and high-performance payloads on CubeSats, the need to migrate toward less congested frequency bands and wider bandwidth allocations are becoming increasingly evident. In this context, as the development of the ground infrastructure - the CubeSat Control Centre (C3) — approaches its final stages, the CubeSat PoliTO Team at Politecnico di Torino is focusing on the testing and finalization of the S-band communication chain, aimed at enabling enhanced downlink and uplink capabilities. The team has been developing, operating, and maintaining C3 as both a ground station and a mission control center, with the educational objective of enabling students to manage end-to-end space missions. C3 currently supports communications in amateur VHF and UHF bands and is being extended to include S-band capabilities. Following the successful testing and integration of the VHF and UHF RX and TX chains, the team has focused on the development, testing and validation of the S-band communication line. The campaign began with the characterization of individual RF components, including amplifiers stages and cables. Key parameters such as S-parameters, gain, matching, and spectral performance were measured using a Vector Network Analyzer (VNA) and Spectrum Analyzers (SA). A progressive integration approach was adopted, incrementally combining validated components until the complete RX and TX chains were assembled and verified also to maximize the educational output value. Although the selected RF amplifiers are commercial off-the-shelf (COTS) units, the integration within the existing ground station architecture required the development of dedicated custom support boards. These boards provide proper biasing, protection circuitry, and electrical interfacing, ensuring seamless integration with the broader C3 system. Beyond the technical achievements, the project carries a strong formative impact. The S-band upgrade provided team members, coming from diverse academic backgrounds, with hands-on experience in RF design, measurement techniques, system engineering, and structured AIV-T processes. The activity fostered interdisciplinary collaboration, practical problem-solving skills, and a deeper understanding of real-world ground segment development. This paper presents the design choices underlying the S-band communication chain, the integration challenges encountered when interfacing with a pre-existing multi-band ground station, and the development of custom hardware solutions to bridge gaps between COTS components and the rest of the system. The adopted testing philosophy, based on incremental validation and educational return, is discussed providing reference practices for similar academic ground stations.