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Flashcards
SSR: ADS-B
Automatic Dependent Surveillance - Broadcasting => ADS-B ==> different from primary and secondary radar system ==> uses the navigation information available from the on-board systems of the aircraft together with a transmitting device
==> Broadcasted via ADB's OUT and receives teh information ADS-B IN
=> Mode S broadcast interrogation (Befragung) transmit informaton to all modes transponder
SSR: Mode S Interrogator
It used a new pulse = P5 => overlays P6 synchronization => Data block may be short (56 bit) or long (112 bit) and used 25 different uplink formats !!
SSR: How to avoid unnecessary transponder activity Mode S
1. will receive all-call interrogations during the all-call periods => the ground station now decodes the reply and has ahus acquired => during the following roll-call periods => the selective roll call interrogations contain informations that instructs to disregard further all-calls from all intergoations using the same IC ==> Period of 18 seconds
SSR: Mode S not only triggered by ground stations but also by othe raircraft => how many downlinks
25 downlinks formats DF00 to DF0024=> the data bock is pulse position modulated (PPM).
SSR: Under which item you must enter the Transponder mode by a flight plane?
Item 7
Why is a SSR immune to teh effetcs of storm clutter?
SSR does not analyst backscatter ( Echo)
backscatter
echo
What is teh difference between a mode S interrogation using a short P4 pulse and a mode S interrogation using a long P4 pulse?
Short P4 elicits replies from mode A/C transponder only. Long P 4 elicits replies fromm all transponder
The transponder of an aircraft can provide reply signals in response to interrogations from:
SSR and aircraft equipped with traffic collision avoidance system (TCAS II)
MLS: a MLS signal should extend 20 NM from threshold with lateral and vertical accuracy of?
ILS: localizer freuquency?
Zwischen 108.00 - 111.975 MHz, aber !! Nur odd decimals = ungerade nach den pumkt=> 109.15 MHz
MLS: najor ground based components?
Separate azimuth and elevation transmitter + DME facility
MDI: MH oder CH
RMI: MH oder CH
MDI: MH RMI: CH jedoch deviation 0 => MN = CN
The advantage of the use of SLOTTED antennas in modern radar technology is to
virtually eliminate lateral lobes and as a consequence concentrate more energy in the main beam
In order to ascertain whether a cloud return on an Aircraft Weather Radar (AWR) is at or above the height of the aircraft, the tilt control should be set to: (Assume a beam width of 5°)
2.5 degrees up
A Mode C transponder reports altitude in increments of:
100 ft
Fruit means?
Fruit = False replies unsynchronised to interrogator transmission
Garbling means?
Garbling = Targets to close to each other.
A primary radar operates on teh principle of ?
pulse technique
Max range obtainable from ATC Long Range Surveillance Radar is approximately....
300 NM
PRF was ist das und wie rechnet man es aus ?
PRF pulses per seconds =\(PRF = {300'000 km/s \over 2 * Range (km) }\)
Which combination of characteristics gives best screen picture in a primary search radar?
Effect of multippath signals (coming from the same aircraft) at the ground VHF Direction Finder station?
They may result in bearing errors
VDF meaures the bearing of the aircraft? die 4 Qs?
reference to rue or magnetic north AT THE STATION => QTE; true track to the station QUJ: True track from the station QDR: magnetic track from the station QDM: magnetic track to the station
To provide a pilot with the position of the aircraft in the absence of radar, ATC must have at its disposal at least:
two VDF's at different locations, able to take bearings simultaneously on the transmitted frequency
Ground direction finding at aerdormes utilises which frequencies ?
VHF at civil aerodromes and UHF at military aerodromes
the advabtage of teh use of slotted antennas in modern radar technology is to:
virtually eliminate lateral lobes and as a consequences concentrate more energy in the main beam
An electromagnetic wave consists of an oscillating elecrtrical field (E) and an oscillating magnetic field H. Which statement is correct?
An AC will be induced:
a reason that GPS satelitted use helical antenna is:
because the signal has a circular polarization
I it basic type. a dipole antenna adapted for a frequency of 110 MHz will have a wire length of:
136 cm==> 3'000'000 km(s / 110 MHz ==> die hälfte = 136cm
The simplest type of the antenna construction is a:
dipole antenna which is a wire of length equal to one half of the wavelength
GIven a wire fed with AC and a second wire parallel to, but remote from it. The result will be:
the first wire will radiate electromagnetic waves into space and AC current will be included in the second wire
directional antennas?
loop antenna, parabolic antenna, slotted plana antenna, helical atenna
A loop antenna is commonly used in?
ADF receivers
Considering a primary radar system what kind of aerial are used?
What makes Parabolic reflectors?
Parabolic reflectors create more side lobe activity, which results in a waste and a smaller range of the main beam. Newer technologies use flat plate antennas with a less side lobe activity and a greater range. Another advantage is a smaller size of the antenna and less weight for creating the same performance
A radio wave with a horizontal magnetic component H would be best received by a xy dipole antenna
vertical
Rhe phenomenon of a change in direction of a radio wave occuring due to a change in its speed is called?
refraction
Wo kommen VHF/UHF vor?
quasi-optical = direct wave. If you consider the classification of the type of waves and their propagation paths, you can see, that VHF/UHF waves are space waves, but no sky waves. Space waves consist of direct waves, ground reflected waves and sky waves and HF as sky waves
