Radar | Weather Radar Flashcards
Weather radar is only a ___ means
secondary
The primary purpose of weather radar is to detect the sort of rainfall that would indicate ___
thunderstorms and turbulence
WX radar is required on aircraft carrying more than _ PAX, under IFR or at night when there could be TS or other hazards along the route
9
C Band is between __ and __ _Hz
4000 8000
The C Band will illuminate storms ___ nearby precip a better
beyond
X Band is between ___ and ___ _Hz
8000 12,500 MHz
X band provides __ resolution, though the higher frequencies are subject to scattering and absorption from ___ raindrops
better small
The wavelength to detect a 1/2 centimeter raindrop is around _ cm at __ _Hz
3 10 GHz
Airborne weather radar will (not) detect snow and cat
not
__ clouds are most readily detected
Cu
The antenna can be ___ or ___
parabolic flat
A ___ scanner reduces the power demand and sidelobes
flat
In weather mode, the beam is ___, between _ and _ degrees, and ___ shaped
narrow, 3, 5, cone
For mapping, the beam is ___ and ___ shaped
wide fan
A clear area is more likely to indicate ___ water droplets as they will totally absorb the energy as they approach the size of the radar wave
large
The greatest echoes come from ___
rain
The __ of the drops is more important than the number
size
Swept gain ___ the receiver gain the instant the pulses are fired, then progressively increases so that the echoes from distant ranges are amplified more than closer ones
decreases
Full use below ___ft should be avoided
500
Ground testing requires tilting __ in weather mode
up
Tilt ___ until you see ground returns, then __ until they disappear, then __ _ more degrees
down, up, up, 2
The tilt should be __ at lower altitudes, and ___ at higher ones
higher lower
MAP mode uses a ___ radiation pattern with a ___ squared antenna, to scan a large ground zone.
cosecant cosecant
Hail will show up better when gain is ___
reduced
Target separated by a distance less than ___ the beam diameter will merge and appear on the display as one
half
The minimum height above a storm cloud should be ___ft for every 10kts of wind speed
1000
A hook indicates ___ wind circulations and will be found in TS with marked windshear in the ___ levels
strong, middle
A finger with sharp contours means a ___ storm, fuzzy means a ___ storm.
growing, dissipating
A U shape on a weather radar shows strong updraughts surrounded on ___ sides by the sort of heavy precip associated with downdraughts.
three
Scalloped edges show severe attenuation due to heavy ___
precipitation
Ground radar for longer range has ___ frequencies and ___ wavelengths, __ PRFs, and ___ pulses to get maximum range with the lowest attenuation.
lower, longer, lower, larger
Typical ground radar coverage is ___-___nm with a frequency of ___ _Hz, and __ cm wavelength.
250-300, 600 MHz, 50
Aircraft Surface Movement Radar operates on the _HF band, __ _Hz, using a __ RPM antenna
SHF, 16 60
When an operator increases the range on a radar-display, the PRF ___ and the pulse length ___
decreases increases
