What is the frequency designated to radar altimeters?

2.4 to 4.2 GHz

4.2 to 4.4 GHz

13 to 14 GHz

500 to 1 GHz

Correct Answer : 4.2 to 4.4 GHz

Explanation : The frequency band of 4.2 to 4.4 GHz is assigned to radar altimeters. This frequency band is high enough to result in a reasonable small sized antenna to produce 40° to 50° beam but significantly low so that attenuation by rain is minimum.

Recently Updated in Avionics Questions

Anti reflection coated optics reduce ________

Refraction

Reflection angle

Intensity of star image

Optical transmission losses

Correct Answer : Option (D) : Optical transmission losses

Explanation : For anti-reflection coated optics, the optical transmission losses may be 1% or 2% at each air to glass or glass to air optical control surface within the telescope, including windows or sensor covers or surfaces. For uncoated optics, the loss per surface is about 4% to 5%.

The ratio of the focal length to aperture is called the ________

Focal number

f/ number

Critical aperture

Effective aperture

Correct Answer : Option (B) : f/ number

Explanation : The ratio of focal length to aperture is called the f/ number. For example, an f/10 telescope may have a 30 in. focal length and a 3 in. aperture.

The physical size of the star depends upon _____

Shape of image

Colour of image

Angular size of image

Intensity of image

Correct Answer : Option (C) : Angular size of image