Unguided Media — Wireless
How can data travel with no wire at all?
- Describe radio, microwave, infrared and satellite transmission
- Compare wireless media on speed, range and cost
- Give one PNG use case for each
Overview
Unguided media send signals through open air or space using electromagnetic waves. No cable is needed, but the signal is shared with everyone in range, which affects speed, security and reliability. Wireless is how most Papua New Guineans first meet the internet.
Radio and Wi-Fi
Radio waves travel long distances and pass through walls. Wi-Fi is a short-range form of radio (2.4 GHz or 5 GHz) built for buildings. Digicel and Vodafone mobile signals are radio in licensed bands. Speed drops with distance, walls, and how many devices share the channel.
Microwave and satellite
Microwave links use narrow high-frequency beams between two dishes with a clear line of sight — good for connecting mountain towers across a valley. Satellite (VSAT, Starlink) bounces the signal off orbit; it reaches anywhere on the map but adds latency. Many remote PNG schools, clinics and lodges rely on VSAT because no fibre or mobile tower is nearby.
Infrared
Infrared uses light just below the visible range. It is short-range and needs line of sight — TV remotes, older phone data links, some medical instruments. It is now mostly replaced by Bluetooth for phone-to-phone transfer.
Wireless Comparison Table
- Draw a 4-row × 5-column table: rows = radio, microwave, infrared, satellite; columns = range, speed, cost, EMI risk, PNG example.
- Fill it in from the lesson and your own knowledge.
- Which wireless option can reach a remote village with no mobile tower?
Reveal answer
Satellite (VSAT or Starlink).
- Why does satellite feel 'slow' for video calls?
Reveal answer
The signal must travel to orbit and back, adding latency.
- Name one everyday device that still uses infrared.
Reveal answer
A TV remote control.
Look on the roof of a school building or nearby shop. Can you spot a VSAT dish, a microwave dish or a mobile antenna? Sketch what you see.