Major Earth Station Equipment - ITSO · Antenna Control Unit (ACU) – Manually position and...

6/10/5244 - 1

Major Earth Station Equipment

6/10/5244 - 2

Major Earth Station Equipment

ANTENNA – Types

– Parameters

Uplink – Modulation

– Up-converters

– Transmitters

– Inter Facilities Link

RF Downlink – LNA / LNB

– Down-converters

– Demodulation

– Inter Facilities Link

6/10/5244 - 3

Antenna

A satellite earth station antenna

– An effective interface between the uplink equipment and free space

– Must be directional to beam an RF signal to the satellite

– Requires a clear line of sight between the antenna and the satellite

HPA

Antenna

Free space

HPA

Free space

6/10/5244 - 4

Antenna

6/10/5244 - 5

ANTENNA

ANTENNA PARAMETERS:

GAIN

G (dBi) = 20.4 + 20 Log f + 20 Log D + 10 Log h

f = frequency in GHz

D = diameter in meters

h = antenna efficiency in decimal format

What should be the gain of a 9.3 m C-band antenna at 6.4GHz that is 62% efficiency ?

G = 20.4 + 20 Log 6.4 + 20 log 9.3 + 10 Log 0.62

G = 20.4 + 20 ( .806179) + 20 ( .968482) + 10 ( -0.2076)

G = 20.4 + 16.12 + 19.37 - 2.08

G = 53.81 dBi

6/10/5244 - 6

ANTENNA

BEAMWIDTH:

For a given antenna, the higher the frequency the

narrower the 3dB beamwidth. Therefore the receive band will

be broader than the transmit.

For a given frequency band the larger the antenna

aperture the smaller or narrower the beamwidth.

θ (deg.) = 21

f D

f = frequency in GHz

D = diameter in meters

6/10/5244 - 7

ANTENNA

BEAMWIDTH:

6/10/5244 - 8

Antenna

– Manual movement

– Provides coverage of the entire satellite arc

– Peaked on satellite with no further adjustments

– Motorized – Azimuth ± 180o from antenna center line (CL) – 5 - 90o – Tracking satellites in transfer orbit

– Typically Motorized

– Azimuth ± 60o from center line (CL)

– 5 – 90o Elevation

– Full time service

– Occasional use on multiple satellites

Full Motion

Limited Motion

Fixed

6/10/5244 - 9

Antenna

– Computer Track

• Predict data from computer controls antenna movement

– Installed at base of the antenna (“Jog Controller”) – Toggle switches for AZ (CW/CCW), EL (UP/Down) and Polarizer – Serial data link for remote control with a computer – Transducers provide AZ & EL and Polarizer angle readouts

Antenna Position Controllers (APC)

Antenna Control Unit (ACU) – Manually position and polarize the antenna

– Preset satellite locations stored in memory – Step Track

• Requires a suitable receiver to provide signal level to the ACU

• Back and forth movement in AZ and EL to ensure peak signal level – Memory Track

• Creates a model of satellite motion for a twenty-four hour period

• Uses this model to track the satellite

6/10/5244 - 10

Antenna

– Mono-pulse

• Relative signal phase and the sharp slope of a tracking null is used to determine peak position

• It is not necessary to step the antenna to determine satellite target orientation relative to the antenna’s RF axis

• Utilizes an electrical means (phase comparison) rather than a mechanical means (antenna stepping) to determine satellite orientation

• Responds more accurately and faster to satellite dynamics

• Primary use is for tracking transfer orbits

Antenna Control Unit (ACU)

6/10/5244 - 11

Antenna Efficiency

Efficiency can never be 100%

Well-designed antennas have efficiency ratings of 50 - 70%

– 60 – 65 % typical

Efficiency is affected by:

– Spar and feedhorn blockage

– Subreflector alignment and placement

– Subreflector surface tolerance and design

– Main reflector surface tolerance or deviation

– Feed horn loss

– On axis alignment

– Polarization purity

6/10/5244 - 12

Antenna Types

Prime Focus parabolic reflector – Center Feed

– Feed & strut blockage can be large

– High feed line loss

– Both TX and RX

– Poor G/T performance

OMT

Feed

SPAR

RF

RF

MAIN REFLECTOR

6/10/5244 - 13

Antenna Types

Parabolic reflector Cassegrain – Typical use 5m or larger

– Parabolic main reflector

– Hyperboloidal subreflector

– Subreflector and strut blockage small

– Small feed line loss

– Good G/T

RF

SUBREFLECTOR HYPERBOLOIDOMT

MAIN REFLECTOR

RF

SPAR

Feed

SPAR

6/10/5244 - 14

Antenna Types

Parabolic reflector Gregorian – Typical use 5m and larger

– Parabolic main reflector

– Ellipse subreflector

– Subreflector and strut blockage small


– Good G/T

RF

SUBREFLECTOREllipseOMT

MAIN REFLECTOR

RF

SPAR

Feed

SPAR

6/10/5244 - 15

Antenna Types

Parabolic reflector offset feed – Typical 3.7m and smaller

– No feed blockage


– VSAT applications

R F

R F

MAIN REFLECTOR

OMTSPAR

Feed

6/10/5244 - 16

Antenna Types

Simulsat – Receive Only

– Captures signals across a 70° view arc

– Up 35 satellites are received with uniform performance

– Each satellite illuminates a specific area

– Signals reflect to their corresponding C or Ku-Band feed

– Feeds are adjusted, no antenna movement

6/10/5244 - 17

Antenna Types

– The system noise temperature is also reduced because the receiver looks at the cold sky instead of the warm earth

In a direct feed reflector, the feed horn is located at the focus or may be offset to one side of the focus

Large earth station antennas have a subreflector at the focus

– The subreflector permits the antenna optics to be located near the base of the antenna

– Reduces losses because the length of the waveguide between the transmitter or receiver and the antenna feed is reduced

6/10/5244 - 18

Antenna Subreflector

Gregorian

– The subreflector is concave with an ellipsoidal surface

– Ellipsoidal? A geometric surface or a solid figure shaped like an oval. Any section through an ellipsoid is either an ellipse or a circle.

Cassegrain

– The subreflector is convex with an hyperboloidal surface

– Hyperboloidal? A mathematical surface whose sections parallel to one coordinate plane form ellipses and those parallel to the other two coordinate planes form hyperbolas

6/10/5244 - 19

Antenna Focal Distance (f/d)

Focal Distance (f/d)

– To calculate: f/d = D2/16d • D = Antenna Diameter

• d = Depth of Parabola

d = 0.6m

D = 3.8m

f/d

D = 3.8m

d = 0.8m

f/d

f/d = D2/16d

D = 3.8 m D = 149.6 in

d = 0.6 m d = 23.63 in

f/d = 1.504 m f/d = 59.23 in

f/d = D2/16d

D = 3.8 m D = 149.6 in

d = 0.8 m d = 31.5 in

f/d = 1.128 m f/d = 44.42 in

6/10/5244 - 20

Antenna

Deep dish antenna – Short focal length decreases the feedhorn’s ability to illuminate the

entire reflector area providing less gain

– Can provide advantages

• Low elevation angles

• Terrestrial interference

– Better antenna noise temperature

Shallow dish antenna – Long focal length increases the feedhorn’s ability to illuminate the

entire reflector area providing good gain

– More susceptible to:

• Earth noise at low elevation angles

• Terrestrial interference

– Affects antenna noise temperature

6/10/5244 - 21

Antenna De-Ice

Fabric Cover

– Prevent snow/ice accumulation in the dish

Freezing perception will impact antenna performance

– Snow or ice on the reflector surface

• Attenuates the signal

• De-focus the antenna

Area’s with freezing perception require antenna de-icing Electric

– Blankets glued to the back of the reflector

– Forced hot air with the back structure enclosed

Natural gas

– Forced hot air with the back structure enclosed

Rain Blower

– Blows air across feed input to prevent water buildup

6/10/5244 - 22

Antenna Feed Assembly

6/10/5244 - 23

Antenna Feed System

Rain Blower

– Blows air across feed input to prevent water buildup

1 Port – Receive Only

2 Port – Two Receive – One Transmit and One Receive

3 Port

– One Transmit and Two Receive

4 Port – Two Transmit and Two Receive

Polarization adjustment

– Single plane, transmit and receive are fixed and both rotate

– Dual plane, transmit and receive rotate separately

6/10/5244 - 24

Ortho Mode Transducer (OMT)

– Changes feeds circular W/G to two rectangular W/G’s – Separates and directs signals of two different polarities – Determines isolation for Circular Polarization

OMT and TRF

Transmit

TRF

Feed

LNA

Receive

H

V

4 port feed will have an OMT and TRF for each polarity

Transmit Reject Filter (TRF)

– Blocks transmit power from the Low Noise Amplifier

6/10/5244 - 25

Antenna Patterns

6/10/5244 - 26

Antenna Pattern

•3D Radiation Pattern

6/10/5244 - 27

Antenna Pattern

•Cut Through Radiation Pattern

6/10/5244 - 28

FCC / ITU requirements for transmit patterns – 29-25log q from 1 to 7o

– 8 dBi from 7 to 9.2o

– 32-25log q > 9.2o

Antenna Pattern

Deg 29-25 log q from peak

1 29.0 15.2

2 21.5 22.7

3 17.1 27.1

4 13.9 30.3

5 11.5 32.7

6 9.5 34.7

7 7.9 36.3

8 8.0 36.2

9 8.0 36.2

10 7.0 37.2

11 6.0 38.2

How are the curves applied?

– Calculations are subtracted from antenna gain

– i.e. antenna gain = 44.2 dBi

– Higher gain antenna will provide more discrimination

– i.e. 50 dBi – 29 = 21 dB

6/10/5244 - 29

Antenna Pattern

Deg from peak

1 15.2

2 22.7

3 27.1

4 30.3

5 32.7

6 34.7

7 36.3

8 36.2

9 36.2

10 37.2

11 38.2

6/10/5244 - 30

Antenna Pattern

Co-pol pattern

Cross-pol pattern

6/10/5244 - 31

Uplink

6/10/5244 - 32

Uplink Components

Uplink Block Diagram – Modulator / Modem

– Up-Converter

– Power Amplifier

– Antenna

– Inter Facility Link (IFL)

• Fiber Optics

• Co-axial cable

• Patch Panels

• Combiners / Splitters

• Waveguide

Modem Up-Converter Transmitter FeedIFL IFL IFL

Antenna

Simplified Uplink Block Diagram

6/10/5244 - 33

Up-Converter (U/C)

6/10/5244 - 34

Up-Converter (U/C)

The method used to achieve the conversion is heterodyning. That is the mixing of two different frequencies into a non-linear device ( mixer ) to produce two other frequencies equal to the sum or difference of the first two, while maintaining it’s characteristics

A device that converts an input signal known as the intermediate frequency (IF) to a desired higher frequency without disturbing the intelligence (modulation) on the incoming signal

6/10/5244 - 35

Up-Converter (U/C)

– 140 MHz to L-Band • 140 ±72 MHz input

• 950 – 1450 MHz output

• Non inverting

• 72 MHz bandwidth

70 / 140 MHz IF to L-Band

– 70 MHz to L-Band • 70 ±18 MHz input

• 950 – 1450 MHz output

• Non inverting


6/10/5244 - 36

Up-Converter (U/C)

L-Band to C-Band – 950 - 1450 MHz input

– 5.925 – 6.425 GHz output

– Non inverting (4.900 GHz LO)

– Inverting (7.375 GHz LO)

– 500 MHz bandwidth

L-Band to Ku-Band – 950 - 1450 MHz input

– 14.00 – 14.50 GHz output

– Non inverting (LO = 13.050 GHz)

– Inverting (LO = 15.450 GHz)


6/10/5244 - 37

U/C Frequency Calculations

– Modem IF Frequency = 74.5 MHz (6104.5 – 4900 -1200 + 70) – Uplink freq (-) BUC LO freq (-) U/C center freq (+) 70 MHz

Modem 70 Mhz to L-Band BUC74.5 MHz 1204.5 MHz HPA6104.5 MHz

Center Frequency1200 MHz

LO = 4900 MHz

70 to L-Band to C-Band (Non Inverted)

– Center Frequency of transponder (6100 MHz)

– LO frequency of the BUC (4900 MHz) – Center frequency of Up-Converter = 1200 MHz (6100 – 4900)

• Bandwidth center freq (-) BUC LO freq

– Carrier Uplink Frequency 6104.5 MHz

6/10/5244 - 38

Modem IF to L-Band BUC65.5 MHz 1270.5 MHz HPA6104.5 MHz


LO = 7375 MHz


– Modem IF Frequency = 65.5 MHz (7375 - 6104.5 - 1270 + 70) – BUC LO freq (-) Uplink freq (-) U/C center freq (+) 70 MHz

70 to L-Band to C-Band (Inverted) – Center Frequency of transponder (6100 MHz) – LO frequency of the BUC (7375 MHz)

– Center frequency of Up-Converter = 1275 MHz (7375 – 6100) • BUC LO freq (-) Bandwidth center freq


6/10/5244 - 39



LO = 13050 MHz


– Modem IF Frequency = 77.5 MHz (14207.5 – 13050 -1150 + 70) – Uplink freq (-) BUC LO freq (-) U/C center freq (+) 70 MHz

70 to L-band to Ku-Band (Not inverted) – Center Frequency of transponder (14200 MHz) – LO frequency of the BUC (13050 MHz) – Center frequency of Up-Converter = 1150 MHz (14200 – 13050)

– Bandwidth center freq (-) BUC LO freq


6/10/5244 - 40





LO = 15540 MHz

70 to L-Band to Ku-Band (Inverted) – Center Frequency of transponder (14200 MHz)

– LO frequency of the BUC (15540 MHz) – Center frequency of Up-Converter = 1340 MHz (15540 – 14200)

– BUC LO freq (-) Bandwidth center freq

– Modem IF Frequency = 62.5 MHz (15540 - 14207.5 - 1340 + 70) – BUC LO freq (-) Uplink freq (-) U/C center freq (+) 70 MHz

6/10/5244 - 41

Up-Converter (U/C)

70 MHz to C-Band – 70 ±18 MHz input

– 5.850 – 6.425 GHz output

– Non inverting


140 MHz to C-Band – 140 ± 36 MHz input – 5.850 – 6.425 GHz output – Non inverting – 72 MHz bandwidth

6/10/5244 - 42


– Modem IF Frequency = 74.5 MHz (6104.5 – 6100 + 70) – Uplink freq (-) U/C center freq (+) 70 MHz

Modem Up-Converter74.5 MHz HPA6104.5 MHz


70 MHz to C-Band – Center Frequency of transponder (6100 MHz)

– Center frequency of Up-Converter = 6100 MHz


6/10/5244 - 43




140 MHz to C-Band – Center Frequency of transponder (6100 MHz)

– Center frequency of Up-Converter = 6100 MHz


– Modem IF Frequency = 144.5 MHz (6104.5 – 6100 + 140) – Uplink freq (-) U/C center freq (+) 140 MHz

6/10/5244 - 44

Up-Converter (U/C)

70 MHz to Ku-Band – 70 ±18 MHz input – 14.00 – 14.50 GHz output – Non inverting – 36 MHz bandwidth

140 MHz to Ku-Band – 140 ± 36 MHz input – 14.00 – 14.50 GHz output – Non inverting – 72 MHz bandwidth

6/10/5244 - 45


– Modem IF Frequency = 77.5 MHz (14207.5 – 14200 + 70) – Uplink freq (-) BUC LO freq (-) U/C center freq (+) 70 MHz



70 MHz to Ku-Band – Center Frequency of transponder (14200 MHz)

– Center frequency of Up-Converter = 14200 MHz – Carrier Uplink Frequency 14207.5 MHz

6/10/5244 - 46


– Modem IF Frequency = 147.5 MHz (14207.5 – 14200 + 140) – Uplink freq (-) BUC LO freq (-) U/C center freq (+) 140 MHz



140 MHz to Ku-Band – Center Frequency of transponder (14200 MHz)

– Center frequency of Up-Converter = 14200 MHz – Carrier Uplink Frequency 14207.5 MHz

6/10/5244 - 47

U/C Attributes

Parameter Typical Value* Unit

Return Loss > 20 dB

Noise Figure < 15 dB

RF output

Return Loss > 20 dB

Spurious

Non-Carrier < -80 dBm

Carrier < -60 dBm

Third Order Intermodulation at 10 dB backoff from rated output power

< -40 dBc

Third Order Intercept > 23 dBm

IF/RF Performance (Transfer)

Gain Stability vs. Temperature at 0-50 Celsius Degree

< 1 dB

Gain Stability vs. Temperature 24 Hr. at constant drive and temp.

< 0.25 dB


AM/PM conversion at rated output power

< 0.1 degree/dB

Group Delay (per 40 MHz)

Linear < 0.05 ns/MHz

Parabolic < 0.01 ns/MHz2

Ripple < 1 ns P-P

Frequency Stability

Daily < 5 x 10-9

Yearly < 1 x 10-7

Over Operating Temperature < 1 x 10-8

Phase Noise (IESS 308/309 phase noise profile)

10 Hz < -30 dBc/Hz

100 Hz < -60 dBc/Hz

1 kHz < -70 dBc/Hz

10 kHz < -80 dBc/Hz

100 kHz < -90 dBc/Hz

1 MHz < -90 dBc/Hz

* For better performance, the selected value should be less or greater than as indicated

6/10/5244 - 48

Transmitters High Power Amplifier (HPA)

6/10/5244 - 49

Transceiver

Transceiver – Combination Power Supply, Up / down converter, HPA and LNA

– Mounted on / at the antenna

– 70 or 140 MHz IF input

– C-Band output

– Single or dual synthesized converters

• Uplink

• Downlink

Power Supply

Up-Converter

Down-Converter

TXIF

RXIF

SSPA

LNA

Transceiver Block Diagram

6/10/5244 - 50

Transceiver Attributes


IF Input VSWR < 1.5 : 1

RF Output VSWR < 1.5 : 1

Gain Flatness over any 40 MHz

< 1 dB

Gain Stability vs. Temperature (0-50 Celsius Degree)

< 1.5 dB

Spurious at rated output power

< -50 dBc

Harmonic Output at rated output power

< -50 dBc


< -26 dBc

Receive Characteristics

RF Input VSWR < 1.5 : 1

IF Output VSWR < 1.5 : 1


< 1.5 dB



< 1.5 dB

Noise Figure < 1 dB

Frequency Stability

Daily < 5 x 10-9

Yearly < 1 x 10-7



10 Hz < -30 dBc/Hz

100 Hz < -60 dBc/Hz

1 kHz < -70 dBc/Hz

10 kHz < -80 dBc/Hz


1 MHz < -90 dBc/Hz


6/10/5244 - 51

Transmitters (HPA)

Block Up-Converter (BUC) – Non linear – Provides up conversion from L-band to C or Ku band – SSPA Provides amplification – Requires external 10 MHz reference – Typical output power 1 to 10 Watts – 500 MHz bandwidth

– Typical application on remote VSAT with L-Band Modem

– ≈ 3 dB OBO for multi carrier operation

L-Band U/C

Bandpass Filter

OUT

SSA SSPA

10 MHz

IN

6/10/5244 - 52

Transmitters (HPA)

Solid State Power Amplifier (SSPA) – Typical output power 5 to 200 Watts


– Non Linear

– L-Band Up-Converter optional

• Requires external 10 MHz reference

• Requires Diplexer

– Typically ≈ 3 dB OBO for multi carrier operation

6/10/5244 - 53

SSPA Attributes

Parameter Typical Value*

Unit

Input VSWR < 1.3 : 1

Output VSWR < 1.3 : 1


< 0.5 dB


< 1 dB



< -65 dBc


< -60 dBc


< -26 dBc


< 2 degree/dB


Unit


10 Hz < -30 dBc/Hz

100 Hz < -60 dBc/Hz

1 kHz < -70 dBc/Hz

10 kHz < -80 dBc/Hz


1 MHz < -90 dBc/Hz




Ripple < 1 ns peak to peak


6/10/5244 - 54

Transmitters (HPA)

Traveling Wave Tube Amplifier (TWTA) – Typical output power 100 – 750 Watts


– Non Linear

– Built in BUC optional

• Requires 10 MHz external reference and Diplexer

– ≈ 7 dB OBO for multi carrier operation

– ≈ 4 dB OBO with linearizer for multi carrier operation

6/10/5244 - 55

Transmitters (HPA)

HPA HIGH POWER AMPLIFIER

• TRAVELING WAVE TUBE AMPLIFIER

• WIDEBAND ( FULL SPECTRUM ) GREATER 500MHz

• NON LINEAR

– SMALL SIGNAL SUPRESSION

– AMPLITUDE TRANSFER CURVE

6/10/5244 - 56

Transmitters (HPA)

TRAVELING WAVE TUBE AMPLIFIER – SMALL SIGNAL SUPRESSION

– AMPLITUDE TRANSFER CURVE

– INTERMODULATION

f 1 - f 2 f 1 + f 2f1 f2

( f 1 - f 2 ) - f 1

6/10/5244 - 57

TWTA Attributes


Unit


10 Hz < -30 dBc/Hz

100 Hz < -60 dBc/Hz

1 kHz < -70 dBc/Hz

10 kHz < -80 dBc/Hz


1 MHz < -90 dBc/Hz

Group Delay (per 40 MHz for C-band / per 80 MHz for Ku-band)



Ripple < 0.5 ns peak to peak


Unit




< 1 dB


< 0.25 dB



< -65 dBc


< -60 dBc


< -24 dBc


< 6 degree/dB


6/10/5244 - 58

Transmitters (HPA)

Klystron Power Amplifier (KPA) – Typical output power 1000 to 3000 Watts – Non linear – 40 or 80 MHz bandwidth – OBO ≈ 2 dB for dual carrier operation

≈ 7 dB for multi carrier operation

6/10/5244 - 59

Transmitters

KLYSTRON POWER AMPLIFIER

NARROWBAND , TUNED CAVITY

FREQUENCY RESPONSE

GROUP DELAY

HIGH POWER

NON-LINEAR

6/10/5244 - 60

KPA Attributes


Unit




< 0.25 dB


< -65 dBc


< -60 dBc


< -28 dBc


< 4 degree/dB


Unit


10 Hz < -30 dBc/Hz

100 Hz < -60 dBc/Hz

1 kHz < -70 dBc/Hz

10 kHz < -80 dBc/Hz


1 MHz < -90 dBc/Hz

Group Delay (per 40 MHz for C-band / per 80 MHz for Ku-band)

Linear < 0.1 ns/MHz


Ripple < 2 ns peak to peak


6/10/5244 - 61

Downlink

6/10/5244 - 62

Downlink Components

Downlink Block Diagram – Demodulator / Modem

– Down-Converter

– LNA

– Antenna

– Inter Facility Link (IFL)

• Fiber Optics

• Co-axial cable

• Patch Panels

• Combiners / Splitters

• Waveguide

Modem Down-Converter LNA FeedIFLIFL

6/10/5244 - 63

Low Noise Amplifier

6/10/5244 - 64

Low Noise Amplifier (LNA)

Lower the Noise Temperature, the better the performance

Low Noise Amplifier

DC Regulator

Input Output

Power

Input Waveguide – CPR-229 C-Band – WR-75 Ku-Band

Output Coaxial connector – N-Type (50 ohm) Standard C-Band – SMA (50 ohm) Standard Ku-Band

Typical 3 stage amplification (Designed to keep noise down) – No Frequency Conversion

“Noise Temperature” is the amount of noise added – Specified in degrees K for C-Band

• 20o – 40oK Typical

– Specified as Noise Figure (NF) for Ku-Band

• 0.7 to 1.0 Typical (50o – 75oK)

6/10/5244 - 65

Low Noise Block Down-Converter (LNB)

Output Coaxial connector

– N-Type (50 ohm)

– F-Type (75 ohm)

Low Noise Amplifier

DC Regulator

Input Output

Power

LNA with a Block Down-Converter built in Provides Frequency Conversion

– DRO (Dielectric resonator Oscillator) • ± 150 kHz to ± 500 kHz C-Band • ± 150 kHz to ± 900 kHz Ku-Band

– PLL (Phase Locked Loop) • ± 5 kHz to ± 25 kHz C-Band • ± 5 kHz to ± 50 kHz Ku-Band

– External (10 MHz reference)

Input Waveguide

– CPR-229 C-Band

– WR-75 Ku-Band

6/10/5244 - 66

Low Noise Amplifier (LNA/LNB)

Frequency stability of LNB critical depending on type of service

Designed to provide the lowest noise contribution as possible – 20o – 40o K noise temperature typical for C-band

– 70o – 90o K noise temperature typical for Ku-band

– 50 to 60 dB Gain typical

Mounted as close as possible to the OMT waveguide ports

One of the most critical components of an antenna system – Major factor in determining the systems figure of merit (G/T)

6/10/5244 - 67

LNA / LNB Attributes LNA


Unit


Noise Temperature for C-Band < 45 K

Noise Temperature for Ku-Band

< 100 K

Output


Gain Flatness over any 40 MHz < 0.2 dB


< 2 dB





Ripple < 1 ns P-P

LNB



Noise Temperature for C-Band < 45 K

Noise Temperature for Ku-Band

< 100 K

Output


Gain Flatness over any 40 MHz < 1 dB

Frequency Stability over Temperature

< 50 kHz


10 Hz < -30 dBc/Hz

100 Hz < -60 dBc/Hz

1 kHz < -70 dBc/Hz

10 kHz < -80 dBc/Hz


1 MHz < -90 dBc/Hz


6/10/5244 - 68

Down-Converter (D/C)

6/10/5244 - 69


A device that converts an RF input signal to a desired lower frequency known as the intermediate frequency (IF) without disturbing the intelligence (modulation) on the incoming signal

The method used to achieve the conversion is heterodyning. That is the mixing of two different frequencies into a non-linear device ( mixer ) to produce two other frequencies equal to the sum or difference of the first two, while maintaining it’s characteristics

6/10/5244 - 70


Ku-Band to L-Band (LNB) – 11.70 – 12.20 GHz input

– 950 - 1450 MHz output

– Non inverted (10.75 GHz)


C-Band to L-Band (LNB) – 3.70 to 4.2 GHz input

– 950 - 1450 MHz output

– Inverted (5150 MHz LO)


6/10/5244 - 71

D/C Frequency Calculations

– Modem IF Frequency = 1270.5 MHz (5150 – 3879.5) – LNB LO freq (-) Downlink freq

Modem LNB1270.5 MHz 3879.5 MHz

LO = 5150 MHz

C-band to L-Band – Inverted C-Band (LNB)

– LO frequency of the LNB (5150 MHz)

– Carrier Downlink Frequency 3879.5 MHz

6/10/5244 - 72



Modem LNB1157.5 MHz 11907.5 MHz

LO = 10750 MHz

Ku-Band to L-Band – Non Inverted Ku-Band (LNB) – LO frequency of the LNB (10750 MHz)

– Modem IF Frequency = 1157.5 MHz (11907.5 – 10750) – Downlink freq (-) LNB LO freq

6/10/5244 - 73


L-Band to 70 / 140 MHz IF

– L-Band to 140 MHz • 950 – 1450 MHz input • 140 ± 36 MHz output • Non inverting • 72 MHz bandwidth

– L-Band to 70 MHz • 950 – 1450 MHz input

• 70 ±18 MHz output

• Non inverting


6/10/5244 - 74


– Modem IF Frequency = 65.5 MHz (5150 – 3879.5 -1275 +70) – LNB LO freq (-) Downlink freq (-) D/C center freq (+) 70 MHz

Modem Down-Converter65.5 MHz LNB1270.5 MHz


3879.5 MHz

LO = 5150 MHz

Inverted C-Band (LNB)


– LO frequency of the LNB (5150 MHz) – Center frequency of Down-Converter = 1275 MHz (5150 – 3875)

– LNB LO freq (-) Bandwidth center freq


6/10/5244 - 75


– Modem IF Frequency = 65.5 MHz (11907.5 – 10750 - 1150 +70) – Downlink freq (-) LNB LO freq (-) D/C center freq (+) 70 MHz

Modem Down-Converter77.5 MHz LNB1157.5 MHz


11907.5 MHz

LO = 10750 MHz

Non Inverted Ku-Band (LNB)


– LO frequency of the LNB (10750 MHz) – Center frequency of Down-Converter = 1150 MHz (11900 – 10750)

– Bandwidth center freq (-) LNB LO freq


6/10/5244 - 76


C-Band to 70 MHz – 3.700 – 4.200 GHz input

– 70 ±18 MHz output

– Non inverting


C-Band to 140 MHz – 3.700 – 4.200 GHz input – 140 ± 36 MHz output – Non inverting – 72 MHz bandwidth

6/10/5244 - 77


– Modem IF Frequency = 74.5 MHz (3879.5 – 3875 + 70) – Downlink freq (-) U/C center freq (+) 70 MHz

Modem Down-Converter74.5 MHz LNA3879.5 MHz


3879.5 MHz

C-Band (70 MHz) – Center Frequency of transponder (3875 MHz)

– Center frequency of Down-Converter = 3875 MHz


6/10/5244 - 78





3879.5 MHz

C-Band (140 MHz) – Center Frequency of transponder (3875 MHz)

– Center frequency of Down-Converter = 3875 MHz


6/10/5244 - 79

Down-Converter (D/C

Ku-Band to 140 MHz – 11.70 – 12.20 GHz input – 140 ± 36 MHz output – Non inverting – Inverting – 72 MHz bandwidth

Ku-Band to 70 MHz – 11.70 to 12.20 GHz input – 70 ±18 MHz output – Non inverting – Inverting – 36 MHz bandwidth

6/10/5244 - 80


Ku-Band (70 MHz)



11907.5 MHz



– Center frequency of Down-Converter 11900 MHz


6/10/5244 - 81


Ku-Band (140 MHz)



11907.5 MHz



– Center frequency of Down-Converter 11900 MHz


6/10/5244 - 82

D/C Attributes



< 0.1 degree/dB




Ripple < 1 ns P-P

Frequency Stability

Daily < 5 x 10-9

Yearly < 1 x 10-7



10 Hz < -30 dBc/Hz

100 Hz < -60 dBc/Hz

1 kHz < -70 dBc/Hz

10 kHz < -80 dBc/Hz


1 MHz < -90 dBc/Hz


RF Input

Return Loss > 20 dB


IF output

Return Loss > 20 dB

Spurious

Non-Carrier < -80 dBm

Carrier < -60 dBm


< -50 dBc


RF/IF Performance (Transfer)


< 1 dB

Gain Stability vs. Temperature 24 Hr. at constant drive and temp.

< 0.25 dB


6/10/5244 - 83

Patch Panels

8:1

IF

Patch Panel

Modem

Modem

Modem

Modem

DATA

Patch Panel

1:8

Up-Converter

Down-Converter

1:2HPA

1:2 LNA

10 dB

Coupler40 dB

Coupler

50 dB

Inject

Coupler

IF

Patch Panel

TP-1 TP-2

TP-3TP-4

Uplink & Downlink Patch Panel and RF monitor block diagram

6/10/5244 - 84

Patch Panels

– Connection between the downlink splitter and modem receive • Monitor output of Down-Converter

Patch Panel’s provide a convenient place to interconnect equipment within the uplink and downlink chains

• Test equipment can be patched in to test either direction (satellite or terrestrial)

Data Patch Panel – Connection between the DTE and Modem

• Ease of testing without having to get into equipment rack to disconnect data cables

IF Patch Panels – Connection between the modem transmit and uplink combiner

• Cross patch modems

– Connection between Combiner and Up-Converter • Monitor output of combiner (All modem transmit carriers)

6/10/5244 - 85

Patch Panels

– Splitter at Down-Converter input (TP-4)

• Monitor full 500 MHz downlink spectrum

RF Monitor Points

– 10 dB coupler on Up-Converter output (TP-1)

• Monitor Up-converter output

– 40 dB coupler at feed input (TP-2)

• Monitor aggregate transmit carriers and power

– Receive inject coupler (TP-3)

• Capability to inject carrier prior to LNA

– Ability to calibrate downlink chain

Major Earth Station Equipment - ITSO · Antenna Control Unit (ACU) – Manually position and...

Documents

Transcript of Major Earth Station Equipment - ITSO · Antenna Control Unit (ACU) – Manually position and...