Mod 9 Flashcards
Reflector
Used for transmitting and receiving microwave frequencies to and from space
Using a parabolic shape results in
Higher Gain
This size of the parabolic reflector is ________ proportionate to the frequency
Inversely
Feed horn
Horn antenna that offers conveying of signals to and from the dish, attached to waveguides
Feed horn linear polarization
Horizontal or vertical polarization adjustments
Feed horn circular polarization
Adjusted right hand or left hand polarization
Feed horns are specific to their
Frequency Band
Job of a modem
Convert the digital data to useable electromagnetic waves during transmit
Opposite during receive
Transmit signal flow
DTE sends digital (baseband)
info to modem > modem turns digital to analog IF > IF sent to up converter for final translation to RF (transmit frequency )
FEC (Forward Error Correction)
Adds artificial redundancy to a data stream and uses this redundancy to fix errors caused by noise and interference
Scrambling
Modems can obfuscate analog data, makes it difficult to read without proper key
Scrambling should not be confused with
Encryption
Coaxial cable
Due to its grounded outer conducting shield, less vulnerable to EMI
GMT is capable of how many uplinks and how many downlinks per hub
1 uplink and 6 downlinks per hub
The GMT has how many transit cases total?
29: 19 antenna cases, 6 electronics cases, 2 PDP cases, 2 spare equipment cases
What cases go on the second pallet
2 Spare equipment and 2 PDP cases
GMT requires how many personnel for setup
2 personel
List all 5 antennas
Small aperture antenna (SAA)
Quick Reaction Satellite antenna (QRSA)
Lightweight High Gain Xband Antenna (LHGXA)
Large Aperture Multiband Deployable Antenna (LAMDA)
Quad band Large Aperture Antenna (QLAA)
PDPs are designed for use with how many amps
60
Local PDP has to be within how many feet of local power source
50 feet
Remote PDPs can be separated from the local PDP up to how many feet
250 feet
Which cases is the NSM in
A and D
ETSSP stands for
Enhanced Tactical Satellite Signal Processor
Define NSM
Synchronous time division multiplexer used in satellite earth terminal
Full duplex
inputs from synchronus data users and digital non secure/secure voice orderwire are multiplexed into a single output aggregate and supplied to modem
Max data rate for NSM
52 Megabits per second
NSM number of ports
26 total: 12 NRZ, 6 TI/E1, 2 HSSI, 6 conditioned di phase ports
only 12 ports can be configured in a single configuration
Port router
Movement of data from ports to the multiplexer channels and from demultiplexer channels to ports
Electronic patch panel, provides interconnectivity of data flow
Monitor and control of the NSM is accomplished through what type of connection
RS232
Establishing a communications channel with another user is to ensure..
you are transmitting a signal through all phases, from modem, to block up converter, to amplifier
during transmission:
Once data from the DTE is received by modem..
Modem modulates the information into an IF
During transmission, From the modem the IF is
Passed to the block up converter where it is translated into a usable RF
During transmission, the final stage is
amplification at the high power amplifier (HPA)
Primary responsibility of block up converter
Translate the IF into RF
Provides a veriable amount of attenuation to the transmission frequency in order to control power output
A high power amplifier is used to
amplify the RF to a level suitable to reach the satellite, provide adequate signal strength for the receiving terminal
Most common Amplifier
Traveling Wave Tube Amplifier (TWTA)
First step of receiving
Receive a downlink RF from the assigned satellite
Ground terminals often receive a weak downlink signal from satellite due to
Distance
ranging from -140dbm and -70 dbm
LNA
Where it is amplified without degrading the signal to noise ratio
Block down converter is used for
Frequency Translation
Block down converts ______ into _______
RF into IF
If will then be sent to modem for data extraction
What case is the timing replaceable unit (TRAK9000) contained in
Electronics case B/E
What allows the antenna to contiously peak on the satellites beacon with minimal drifting
Tracking
SAA
Small Aperture Antenna
Operates on C, X, KU, KA bands
8 reflector panels
tri band HPA must be mounted to the feed boom
2.4 meter (8ft)
QLAA
Quad Band Large Aperture Antenna
Operates on C, X, KU, KA bands
3.9 meter (13ft)
LAMDA
Large Aperture Multi Band Deployable Antenna
Operates in C, X and KU
4.9 meters (16ft)
Requires 3-4 personnel and 45 min to 1 hour
Lightweight High Gain Xband Antenna (LHGXA)
Trailer Mounted
4.9 meter (16ft)
3-4 personnel to set up 45 min - 1 hour
Quick Reaction Satellite Antenna (QRSA)
Trailer mounted
6.1 meter (20ft)
x band
6-8 personnel for setup, 1-2 hours
Primary tracking mode in ACU
Optrack
STORES azimuth, elevation and polarization
Optrack
Forms an Ephermeris model
Optrack
Can predict where the satellite is in the event of signal loss
Optrack
Enhanced version of Optrack, but USER ENTERS intial azmiuth, elevation, and polarization
Position track
Enchanced Optrack, but user enters latitude and longitude
Geotrack
Once it reaches set postion, it wil begin optrack or step track
Geo track
Memory track
After enough stored memory is aquired, the antenna will repeat its track principles day by day