MOD 1 2 3 Flashcards
What is repeatability?
A method of expressing the accuracy of a navigation system, the ability of the user to return to the same location using the same methods
How many pulses does the MASTER station have?
9 pulses
How many pulses do the SECONDARY stations have?
8 pulses
What is the carrier wave pulses tuned to?
100kHz
What pulses has the maximum power in a burst?
the 8th pulse
The receiver measures the _________ between the master and the secondary stations
difference
The difference in distance between 2 stations creates what kinds of lines of position?
hyperbolic
The time between each master station transmission is called __________
group repetition interval (GRI)
What pulse is the principal timing point (timing reference) for a LORAN pulse?
The 3rd pulse because there is no sky wave contamination
How long is each pulse?
Each pulse is 270uS in duration
How much time is between pulses?
1mS, but for the master the last 2 are 2mS
An imaginary line drawn between the master and each secondary
Baseline
The coverage of a LORAN chain is determined by
Power transmitted, distance between, and geometry
What is needed in order to determine a position fix?
2 intersecting lines of position
Whats the typical range coverage of a LORAN chain?
1200 - 1900km
What can be determined by the LORAN data?
Positional latitude and longitude
Flight plan and route info
status of loran chain
course left/right info
What frequencies does the ADF operate on?
190kHz to 1750kHz
What kind of wave propagation does ADF use?
Ground wave
Loop antenna utilizes the _______ field of the wave
Sense antenna utlizes the _______ field of the wave
Magnetic field
Electrostatic field
What does ADF give direction to?
Relative bearing to a non directional beacon (NDB)
7 limitations for ADF
Electrical Interference (electronics within aircraft) Natural interference (lightning storms) (p-stat) Night effect (Shape of ionosphere changes the wave propagation) Coastal effect (lakes and oceans near a coast) Attitude Error (banking could block antenna) Quadrantal error (caused by physical shape of aircraft)
the pattern of the loop and sense together is a
cardioid pattern
what is a goniometer and what does it do?
A resolver made up of coils / windings (sin and cos), and the rotor winding will have a signal of 2 nulls, determining a LOP
What does the balanced modulator produce?
Only the sum and difference frequencies and switches the phase at a rate equal to the servo reference frequency
What does the 90 degree phase shift network do?
Phase shifts the signal by 90 degrees. Compares the output from the loop with the sense. Eventually makes it in phase with the sense, or 180 degrees out of phase
The goal of the goniometer is to point towards what?
One of the 2 nulls, which will tell the servo motor to stop rotating the winding
What does the loop amp do?
Amplifies the loop antenna signal
The loop amp / 90 degree phase / balanced mod lead to what?
The RF amp
What does the RF amp do?
It amplifies the signal from the goniometer (loop antenna) and the sense antenna. In phase = large amplitude signal, out of phase = small amplitude signal
What does the servo amp compare?
If the signal is in phase or out of phase with the servo reference frequency, determining CW or CCW rotation of the motor in the goniometer
Difference between closed loop vs open loop?
Open loop has no feedback from the indicator / receiver back to the antenna
Open loop uses a phase detector or coherent detector
When testing an ADF with an antenna box, it is useful to know the _________
Room factor
If sense is weaker than loop, it will result in a ________
deadspot
If sense is stronger than loop , it will result in a _________
confused needle
Frequency range for VOR is
between 108.00MHz to 117.95MHz
Propagation for VOR is
Space wave or direct wave
Range for localizer (ILS) is
108.10MHz to 111.95MHz
Name of ground station for VOR and DME
VORTAC
VOR is usually a ________polarized and mounted where?
Horizontally polarized mounted on the vertical stablizer
