RF link budget and antenna choice for a rural point-to-point link

Karoo Connect wants to bring broadband to Rietfontein Farm School, 23 km from its tower on Kopjeskop. The school has 210 learners, a new computer lab and no fibre within 60 km. The provider's operations manager wants at least 100 Mbps of usable throughput to the school, with availability of at least 99.9% over a year. The link will use licence-exempt equipment in the 5.8 GHz band.

What you know: - The tower site is at 1,240 m above sea level, with space for an antenna up to 30 m. The school is at 1,105 m, and the school can host a mast of up to 12 m. - A terrain profile along the path is given in task 1, with a ridge about 9 km from the tower. - The radio the provider uses has a maximum transmit power of 25 dBm and a receive sensitivity table by modulation, which you will take from a typical datasheet. - Antenna options are a 30 dBi dish and a 23 dBi flat panel. Short jumper cables lose about 0.5 dB at each end. - The regulator limits EIRP in this band. You must look up the current limit and design within it.

You will draw the path profile, calculate earth curvature and Fresnel zone clearance to set mast heights, build a link budget from transmit power to fade margin, choose antennas including the alignment difficulty, estimate availability from a multipath fade model, pick a channel plan, and write the design with a bill of materials. All of it is calculation in Python or a spreadsheet, with free tools. No radio equipment is needed.

Done looks like a link design an installer can build from: path profile and clearance plot, mast heights, a link budget table, an antenna choice with alignment notes, an availability estimate, a channel plan and a BOM with costs. If 100 Mbps at 99.9% is not possible within the EIRP limit, show what is possible and what would change it.