# Cost-Effective Satellite Ground Stations in Real-World Development for Space Classrooms
## 7 Conclusions  
This research compiled the characteristics of satellites that can be accessed and decoded in orbit. It suggests that building a satellite ground station for a satellite communication and telecommunications classroom should support a VHF frequency range of 136 to 150 MHz, with antennas having a gain of at least 0.05 dB; a UHF range of 400 to 438 MHz, with antennas having a gain of at least 1.74 dBi; and an L-Band range of 1500 to 1700 MHz, with antennas having a gain of at least 28.62 dBi. The station should include both omnidirectional and wide-band directional antennas to cover signals from the sky, space, and terrestrial sources. In the mentioned frequency ranges, the station can receive full-disk multispectral satellite images from GEO satellites, meteorological satellite images from LEO satellites in polar orbit, communications from small satellites like CubeSats, payload communications from the ISS, and signals from other sky and terrestrial sources. For the receiver, this research used the RTL-SDR, a cost-effective and readily available device with high capabilities, covering frequencies of 137-1700 MHz. The device should have a minimum sampling rate of 1 Msps to handle the large number of LRIT satellite signals. To ensure comprehensive signal reception from satellites across the sky, the ground station requires an antenna rotator with an accuracy of better than 2 degrees for tracking both GEO and LEO satellites. The total budget for creating the satellite ground station in this research was under USD 4000, including the terrestrial and LEO satellite antenna systems for USD 2130, the L-band antenna system for GEO satellites for USD 1125, and the SDR server and other equipment for USD 745. This budget is significantly lower than what large organizations might spend, making it suitable for educational purposes in space technology. Signal reception results show that the system can receive and decode data effectively. Using the L-band antenna, the station received images from GK-2A with an SNR of up to 20 dB and signals from Electro-L N3 and Electro-L N4 with an SNR of better than 10 dB, surpassing initial calculations. This indicates that a 1.9 m dish antenna with a  
Figure 23: ADS-B data. gain of 27 dBi is sufficient for receiving and decoding these signals. The VHF antenna successfully received images from NOAA with an SNR of up to 30 dB. The UHF and other band antennas also performed well, demonstrating that the ground station meets the requirements for receiving signals from satellites, the sky, and terrestrial sources. For future development of the satellite ground station, it is recommended to enhance its capability to receive signals in the S-band and X-band ranges, enabling it to cover a broader range of satellite signals. Additionally, upgrading the SDR (software-defined radio) to support a higher sampling rate for receiving image signals would allow for the processing of higher-resolution images. These improvements may increase the estimated cost from the original budget of no more than USD 4000 to approximately USD 5000. Furthermore, regarding the station's location, installing it in a higher position, such as on a tall building, would help reduce obstructions in receiving signals from satellites in low earth orbit (LEO). Methodology, P.S. ; resources, P.S. ; writing--original draft, P.T. and P.S. ; writing--review and editing, P.T. and P.S. ; supervision, P.S. ; project administration, P.T. ; software, P.T. ; funding acquisition, P.T. All authors have read and agreed to the published version of the manuscript. This work was financially supported by [PERSON]'s Institute of Technology Ladkrabang (KMITL), grant number 2567-02-18-002. The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author(s). We express our gratitude to KMITL for their funding and support.