Hi @shufay_u, welcome to the community.
- All the technical requirements for the SatNOGS Rotator v3 (max torque etc.) can be found here.
- Your desired frequency of operation for uplink and downlink depends on several factors. Firstly, you need to take care of legal requirements with RF transmissions. Permission to transmit is usually (most easily) granted to satellite operators operating in VHF, UHF and S-band, although you may be able to be given access to other bands (e.g. X-band) if the demands of your experiment/scientific unit can justify it. Secondly, it depends on what you wish to transmit. If high data rate transmission is a requirement, you are leaning towards a high frequency (e.g. S-band or X-band). Lastly, you’ll need to verify that your frequency of operation is low enough to ensure the reliability of your link budget. The free-space path loss (FSPL) in dB can be derived from the formula: 10log((4πdf/c)^2), where d is the distance between the satellite and your ground station, f is the frequency of operation and c is the speed of light. You can see that the by lowering the frequency of operation, the FSPL gets minimized.
- You’ll need to calculate the link budget for your satellite, both for uplink and for downlink. You can have a great antenna, and have the final signal-to-noise ratio degraded due to losses in the transmission line and what not. Calculating the link budget allows you to account for all the gains and losses of the system.
- I’m not sure I completely understand what you mean by that. If the rotator can handle both antennas, then you won’t have a problem. See the link with all the technical specifications attached in the first point.
- Have you decided on the block diagram of your ground station? Depending on how far the operations center is and whether real-time digital signal processing/data analysis is required or not, you can upload the data from the Raspberry Pi online and apply further analysis to the data at the operations center.
- The built-in CPU temperature monitoring system of the Raspberry Pi should be sufficient. If you’re using a high-power amplifier for TX, it would also be advised to acknowledge the heat that can build up on the unit. A webcam would also help ensuring the rotor is working fine and is not vulnerable to high winds etc. I’d also monitor the technical state of things (e.g. ensure the Raspberry Pi is acquiring the data with no problems like packet drops etc. due to CPU/memory overloading etc. (commands like
top/htopshould help you with that)). I could write some scripts for monitoring the CPU temperature, memory usage and disk space for you if needed. - I’d like to see the block diagram to get a better idea of your project and provide better advice.
