# Cost-Effective Satellite Ground Stations in Real-World Development for Space Classrooms
## 5 Design and Development of Satellite Ground Stations  
### Conceptual Design  
From the data collected in Section 3 from satellites accessible in orbit on the VHF, UHF, and L-band frequencies, initial requirements for designing a ground station capable of receiving signals in these frequency bands were established. This research designed the ground station systems as shown in Figure 5, which are divided into two main antenna systems: the L-band antenna system for GEO satellites and the terrestrial and LEO satellite antenna system. Both of these main systems are connected to an SDR server and classroom, with details as follows. \begin{table}
\begin{tabular}{l l c c c c c} \hline  & **Unit** & **GK-2A** & **FY-2H** & **NOAA-19** & **ARISS** & **FossaSat 2E** \\ \hline Mission & [-] & \begin{tabular}{c} Oceanography \\ and meteorology \\ \end{tabular} & Meteorology & Meteorology & \
\begin{tabular}{c} Amateur radio \\ on ISS \\ \end{tabular} &
\begin{tabular}{c} Demonstrate \\ technology \\ \end{tabular} \\ Orbital altitude/orbit type & [km] & 35,786/CEO & 35,786/GEO & 870/LEO & 460/LEO & 500/LEO \\ Distance \(D\) & [km] & 36,814 & 36,520 & 2509 (at 10\({}^{\circ}\)) & 1595 (at 10\({}^{\circ}\)) & 1695 (at 10\({}^{\circ}\)) \\ Transmitting central & MHz & 1692.14 & 1687.50 & 137.10 & 145 & 401.70 \\ Bandwidth \(B\) & kHz & 300 & 1000 & 50 & 10 & 125 (SF11) \\ Bandwidth \(B\) & dBHz & 54.77 & 60 & 47 & 40 & 50.97 \\ Light speed C & [m/s] & & \(3\times 10^{8}\) & & \\ EIRP transmission & dBW & 25 & 27 & 3.5 & 14 & \(-\)20 \\ Free space path loss \(L_{p}\) & [dB] & 188.33 & 188.24 & 143.17 & 139.72 & 149.10 \\ Polarization loss & [dB] & 3 & 3 & 0 & 3 & 3 \\ Rain attenuation [22] & [dB] & 0.1 & 0.1 & 0 & 0 & 0 \\ Insertion loss & [dB] & 1 & 1 & 1 & 1 & 1 \\ Receiver location & [-] & & & IAAI, KMIT, Bangkok, Thailand & & \\ Az and El antenna pointing & [\({}^{\circ}\)] & \(114^{\circ},54.4^{\circ}\) & \(237^{\circ},60^{\circ}\) & El 10–90\({}^{\circ}\) & El 10–90\({}^{\circ}\) & El 10–90\({}^{\circ}\) \\ Boltzmann constant \(k\) & & & \(-228.6\,\mathrm{dBW/K/Hz}\) & & \\ C/N required & [dB] & 10 & 10 & 10 & 10 & \(-\)17.5 \\ Minimum G/T required & [dB/K] & 3.6 & 6.74 & \(-\)30.93 & \(-\)48.88 & \(-\)22.03 \\ System noise temperature \(T_{s}\) & \(T_{s}\) of dish antenna 1.9 m & [dBK] & 21.88 & 21.88 & 21.88 & 21.88 \\ \(T_{s}\) of grid 60 cm \(\times\) 90 cm & [dBK] & 21.77 & 21.77 & 21.77 & 21.77 \\ \(T_{s}\) of Yagi–Uda UHF & [dBK] & 23.77 & 23.77 & 23.77 & 23.77 & 23.77 \\ \(T_{s}\) of Yagi–Uda VHF & [dBK] & 30.98 & 30.98 & 30.98 & 30.98 & 30.98 \\ \(T_{s}\) of discone & [dBK] & 34.04 & 34.04 & 34.04 & 34.04 & 34.04 \\ Antenna gain \(G_{s}\) required received by & & & & & \\ Dish antenna 1.9 m & [dB] & 25.48 & 28.62 & - & - & - \\ Grid 60 cm \(\times\) 90 cm & [dB] & 25.37 & 28.51 & - & - & - \\ Yagi–Uda UHF & [dBi] & - & - & - & - & 1.74 \\ Yagi–Uda VHF & [dBi] & - & - & 0.05 & \(-\)17.9 & - \\ Discone & [dBi] & 37.64 & 40.78 & 3.11 & \(-\)14.84 & 12.01 \\ \hline \end{tabular}
\end{table} 
Table 3: Numerical calculations of ground station and satellites. L-Band Antenna System for GEO Satellites: Satellites that are easily accessible and demodulated mostly use frequencies in the L-band. Therefore, the antenna system in this section is designed primarily to receive signals from GEO satellites, which are more than 35,800 km away. This research designed this system to use a dish antenna with good signal reception gain and to be mounted on a rotator that adjusts the rotation direction towards the desired satellite. Additionally, it is designed to be placed outdoors in an open area to reduce noise temperature from surrounding signals. 2. Terrestrial and LEO Satellite Antenna Systems: This system is designed to support the frequencies of LEO satellites and other terrestrial frequencies. It includes three directional antennas: Yagi-Uda VHF, Yagi-Uda UHF, and wideband grid antennas [23], all mounted on the same rotator.