Subelement A: RADAR Principles – 10 Key Topics – 10 Exam Questions – 8 Drawings— Topic 3: Frequency and Wavelength
Question 8-3A1
Element 8 (RADAR)Frequencies generally used for marine RADAR are in the ___ part of the radio spectrum.
Explanation
Marine RADAR systems predominantly utilize the Super High Frequency (SHF) band, which spans from 3 to 30 GHz. This band includes common radar frequencies such as S-band (around 3 GHz) and X-band (around 9 GHz).
SHF frequencies offer several advantages crucial for marine radar:
* **Resolution:** Their shorter wavelengths allow for much finer resolution, enabling precise detection and imaging of targets like other vessels, buoys, and shorelines, which is vital for navigation and collision avoidance.
* **Antenna Size:** Shorter wavelengths also permit the use of smaller, more practical antenna sizes that can be easily mounted on ships.
In contrast:
* **VHF (Very High Frequency)** and **UHF (Ultra High Frequency)** have longer wavelengths, providing significantly poorer resolution for radar applications.
* **EHF (Extremely High Frequency)**, while offering even higher resolution, suffers from very high atmospheric absorption and requires extremely complex and expensive components, making it impractical for general marine navigation radar.
Related Questions
8-39E5 How does antenna length affect the horizontal beamwidth of the transmitted signal?8-39E6 What is the most common type of RADAR antenna used aboard commercial maritime vessels?8-3A2 Practical RADAR operation requires the use of microwave frequencies so that:8-3A3 An S-band RADAR operates in which frequency band?8-3A4 A RADAR operating at a frequency of 3 GHz has a wavelength of approximately: