Ew Radar Flashcards
One advantage of using FM over Am is a high resistance to natural interference.
True or false?
TRUE
For intrapulse modulation the ?? Is modulated in some way while the pulse is being ??
RF
Transmitted
The electric field is made to rotate ???
through space in either a left or right direction. This is achieved by transmitting ?? ?? waves of equal amplitude and ?? but 90 degrees out of phase at the same time. This results in the waves rotating in space. The wave rotates rapidly at one full rotation per cycle.
360 Degrees
Two Polarised
Frequency
The total number of pulses within each group
PPG
The interval between each consecutive pulse
PRI
Pulse Repetition Interval
?
PGRI
3 uses of intentional jitter
- Reduce adjacent radar interference
- EPM
- Reduce range / velocity ambiguities
Echo band frequency range
2000-3000 MHZ
Range resolution can be explained as the ability to discriminate between two targets that are the same ?? ?? ??
Bearing and range
Two components of an electromagnetic wave ?? ?? fields
- Magnetic
- Electric
What is the charge possessed by an electron?
Negative
Negative and positive ions are linked by a conductor required to create a controlled flow of electrons in a battery
True or false?
True
Secondary scans are defined as those where the scanning technique is done passively in order to extract movement or position information.
True or false?
False
The cause of intentional jitter are ?? ?? ?? ?? ?? and ?? ?? ?? ??
Equipment failure in timing circuits
Fluctuation in power supplies
A primary radar involves the use of a radar beacon in the target which is passive until triggered by an interrogating radar.
True or false?
False
Learn Frequency table
Frequency table
The scan of a radar is the ?? of a beam of ?? in a ?? in order to cover a region of space
Directing
Energy
Jet pattern
India band frequency range
8000-10000 MHZ
Foxtrot band is frequency range
3000-4000 MHZ
During daylight hours the layers present in the ionosphere are
D, E, F1, F2
Calculate the wavelengths from the following frequencies ( to a whole number)
10Mhz = ?? ?
2 KHz = ?? ??
30 Mhz = ?? ??
10Mhz = 30 m
2khz = 12 km
30 Mhz = 10 m
PISSA
- Polarisation
- Interference
- Selective
- Skip
- Absorption
PRI sliding is pulse interval modulation (PIM) where the PRI’s ?? ?? ?? ?? ?? ?? ?? ?? ?? and then
Repeat but not within the same ?? ??
Increase or decrease between an upper and lower limit
Time period
The range resolution of a radar with a PD of 3.5 usecs is 525m
True
The random PRI variations for discrete /individual elements or values
Discrete
The random PRI variations do not form discrete individual elements or values
Continuous
Total number of different PRI’s in a fixed sequence
Elements
Total number of
PRI’s in a fixed sequence
Positions
The order in which the PRI’s in a fixed sequence are transmitted 400/600/550
Firing Order
Total take to for all PRI’s - staggered pulse train
Cyclic Length
Number of times that the staggered sequence is repeated in 1 second
Cyclic Rate
3 main types of radars that use Dwell and Switch
- Airborne
- Intercept
- Fire Control
- Target tracking
Electrical signals or radio waves are transmitted from an aerial in the form of electric and magnetic fields oscillating at right angles to each other. The ?? Of a radio wave is said to be in the plane of electric field
Polarisation
A radar is intercepted with the following parameters and sequence
PRI’s : 1200, 3200, 1600, 4400 usecs
RF : 8750 MHz
Determine cyclic length usec
FO
Cyclic length = 12000 usec
FO = 1, 2, 3, 2, 4
A wave of ?? amplitude frequency and phase which can be ?? In amplitude, frequency l or phase to convey information
Constant
Varied
Juliet band frequency range
10-20 GHz = 10000-20000 MHz
Charlie band frequency range
500-1000 MHz
