A remote community compares a 5.0 GHz microwave relay, fibre cable and satellite internet. The relay needs line of sight and has moderate installation cost; fibre has the highest installation cost but high capacity and low weather sensitivity; satellite starts quickly but has greater delay and recurring cost. Use c = 3.0 × 10⁸ m/s. (a) Calculate the microwave wavelength. [2] (b) Explain one physical advantage and limitation of each system. [6] (c) Evaluate access, reliability, maintenance, environmental disturbance and long-term cost for residents, school and clinic. [6] (d) Make a conditional recommendation and name missing evidence. [2]

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The microwave wavelength is 0.060 m. No technology is universally best: a recommendation depends on terrain, required latency and capacity, outage tolerance, affordability, maintenance skills and verified whole-life data. (a) Wavelength λ = c/f = 3.0 × 10⁸/(5.0 × 10⁹) = 0.060 m, or 6.0 cm. (b) Microwave relays can span difficult ground without continuous trenching, but obstacles, alignment and some weather conditions can weaken the link. Towers also need power and maintenance access. (b) Fibre offers high capacity, low latency and immunity to radio interference, but trenching or submarine work can disturb land and cost heavily. A single cable break may take specialist repair. (b) Satellite can connect dispersed users quickly without a continuous local route, but signal travel and network architecture increase delay; recurring charges, weather attenuation and provider dependence matter. (c) The clinic may prioritise reliable low-latency consultations, the school capacity and affordability, and residents broad household access. Ownership, repair training, backup power, cultural or land permissions and ecosystem disturbance belong in the decision. (d) Choose fibre where demand and route feasibility justify its whole-life cost; use a microwave backbone where line of sight is dependable; use satellite as an interim or resilient backup. Obtain measured latency, capacity, outage, energy, maintenance and ten-year cost data before committing.

Choose a communication link for a remote community

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