GMDSS Trainer
Subelement A: RADAR Principles – 10 Key Topics – 10 Exam Questions – 8 Drawings— Topic 1: Marine RADAR Systems

Question 8-1A3

Element 8 (RADAR)

What type of transmitter power is measured over a period of time?

Explanation
When transmitter power is measured over a period of time, it refers to **Average power**. **Average power** represents the total power delivered or radiated over an extended duration, taking into account the fluctuations inherent in modulated signals like voice (SSB or AM). While the instantaneous power of a voice signal can vary dramatically from milliwatts to many watts, the average power provides a stable and consistent metric for regulatory limits, power consumption, and the overall heating effect on components. This is particularly important for signals with varying envelopes. **Peak power** (specifically Peak Envelope Power, PEP) is the maximum power reached during the highest point of the modulation envelope. It's an instantaneous measurement, not one taken "over a period of time." **Reciprocal power** is not a standard term used to describe transmitter output power. **Return power** refers to the power reflected back from the antenna system to the transmitter due to an impedance mismatch (measured by SWR), not the power transmitted out.

Ready to test your knowledge?