Skip to content

Radio

Radio Frequency Basics

  1. What frequency bands are typically used for humanitarian VHF and UHF radio communications?
  2. What are the key characteristics of VHF compared to UHF?
  3. Why are VHF radios often used for longer outdoor distances, while UHF radios may work better inside buildings or dense urban areas?
  4. How does frequency affect signal propagation (transmission distance, attenuation, penetration through obstacles, antenna size)
  5. How does terrain (mountains, vegetation, urban environment) influence radio propagation?
  6. What is line-of-sight propagation, and why is it important in VHF/UHF communications?
  7. How does antenna height influence communication range?

Radio Network Architecture

  1. Why do radio systems use separate transmit (Tx) and receive (Rx) frequencies?
  2. What is a repeater, and how does it extend radio coverage?
  3. Why are the Tx/Rx frequencies inverted between the repeater configuration and the user radio configuration?
  4. What is the difference between simplex and duplex communications
  5. What are repeaters, base stations, and mobile radios?
  6. What is coverage planning when deploying a repeater?

RF Equipment and Measurements

  1. What is SWR (Standing Wave Ratio)?
  2. Why is SWR important for radio systems?
  3. What does it mean to measure SWR, and what instruments are used?
  4. What are the consequences of high SWR for a transmitter?
  5. What is a duplexer?
  6. Why are duplexers used in repeater systems?
  7. What does tuning a duplexer mean, and why is it necessary?
  8. What is impedance matching, and why is it important for antennas?
  9. What is the typical impedance used in radio systems (50 ohms)?
  10. What tools are commonly used when deploying radio infrastructure? Like SWR meter, spectrum analyzer, service monitor.

Deployment and Field Setup

  1. What are the steps required to deploy a radio communication system from scratch in a humanitarian operation? Put the following steps in the correct order: Installation, Site assessment, Maintenance, Usage, Planning, Testing,
  2. What are typical power solutions for remote repeater sites?
  3. How would you perform a test coverage after deployment?

Operational Radio Procedures

  1. What are UN radio procedures, and why are they important in humanitarian operations?
  2. What are call signs, and how are they assigned?
  3. What are the rules for initiating a radio call, acknowledging messages, emergency communication
  4. What is radio discipline, and why is it critical during emergencies?

Digital Radio Systems

  1. What is mean SCS ?
  2. What is {TESS+}?
  3. What are the different steps in programming a Radio? Put the steps in the correct order: Test the programming of the Radio, Determine Callsign and SelVID, Program the radio with the correct codeplug, Document what was programmed
  4. What information does a SelV ID represent in the {TESS+} system? What is the difference with callsigns? Which one is used to identify a a user ? a radio?
  5. What mean stun/un-stun in SCS? What happens when a radio is lost or stolen?
  6. Why would administrators remotely stun a radio device?
  7. What is radio silent interrogation, and what operational purpose does it serve?

Antennas

  1. What is antenna gain (dBi)?
  2. What antenna types are commonly used in field deployments?

Interference

  1. What causes radio interference in humanitarian deployments?
  2. How can interference be identified and mitigated?

Handling Radio network failure

  1. What procedures ensure communication continues if the repeater network fails? Backup Radio network ? Satellites phones? Public mobile network?