1. Codan L-Band Block Upconverter (BUC) System
HiSeasNet Training Course

2. Codan L-Band Low Power Block Upconverter (LBUC) -
Technical Overview
Main Components
Low Power BUC
(Block Upconverter)
TRANSMIT
LNB
RECEIVE

3. Low Power Block Upconverter (LBUC)
Transceiver Block Diagram

4. L-Band IF Transceiver - Transmit
Tx IF cable carries:
Tx L-Band IF signal
Frequency Reference from Modem or Interface Unit (10 MHz)
FSK Monitor & Control signals
24 or 48VDC for LBUC supplies

5. L-Band IF Transceiver - Receive
LNB
Optional from Codan
C-Band & Ku-Band versions
Rx IF cable carries:
Rx IF signal from LNB to the Modem
Power from Modem (15 VDC nominal)
Reference Frequency from Modem (10 MHz)

6. LNB Specifications Frequency range
Ku-Band Band GHz Band GHz Band GHz
Gain
Ku-Band 60 dB
Noise temperature
Ku-Band 75 K max

7. Block Upconverter (BUC) Transmit Frequency Conversions
The Block Upconverter (BUC) is responsible for the transmission of the desired carrier at the correct TX frequency. It takes the L-Band input from the modem and upconverts it to Ku-Band.
The BUC is a single conversion system which is frequency inverting. Therefore, the higher the L-Band frequency the lower the transmit RF frequency.
Ku-Band does not require the LO set - only one LO frequency is required to cover the full Ku-Band frequency plan. This LO Frequency is GHz
To calculate the required modem IF frequency for a given RF frequency:
frequencyIF = frequencyLO – frequencyRF

8. BUC Frequency Plan (Ku-Band)
Ku-Band - LBUC
RF: MHz
IF: MHz
LO fixed at MHz
Ku-Band - MBUC
RF: MHz
IF: MHz
LO fixed at MHz
1700 MHz
1450 MHz
950 MHz
14500 MHz
14000 MHz
13750 MHz
IF input
RF output
1450 MHz
950 MHz
14000 MHz
14500 MHz
IF input
RF output

9. Low Noise Block Downconverter (LNB) Frequency Plan
Each Low Noise Block Downconverter (LNB) used in this system has its own internal Reference Oscillator it uses to downconvert the received Ku-Band Signals to L-Band signals. This oscillator is commonly referred to as the Local Oscillator (LO). The LO frequency is different depending on the 3 different Receive Bands.
The three Receive Bands are:
Band GHz LNB LO Freq = GHz
Band GHz LNB LO Freq = GHz
Band GHz LNB LO Freq = GHz
The LNB Downconversion process is a single step process that is NOT Frequency Inverted. This means that the LO frequency is subtracted from the Ku-Band Receive frequency to determine the L-Band Receive Frequency.
frequencyIF = frequencyRF – frequencyLO

10. Frequency Conversion Examples - Transmit
Following are frequency conversion calculation examples based on the R/V Oceanus Shipboard configuration.
Transmit Frequency - Calculate the L-Band transmit frequency to be entered in the Comtech modem to transmit the correct Ku-Band frequency.
Required Transmit Ku-Band Frequency => GHz ( MHz)
BUC LO Frequency => GHz ( MHz)
frequencyIF = frequencyLO – frequencyRF
frequencyIF = MHz – MHz
frequencyIF = MHz

11. Frequency Conversion Examples - Receive
Following are frequency conversion calculation examples based on the R/V Oceanus Shipboard configuration.
Receive Frequency Calculate the L-Band receive frequency to be entered in the Comtech modem to receive the transmitted Ku-Band frequency.
First – Convert the Transmit Ku-band frequency to the Receive Ku-Band frequency. Do this by subtracting the satellite translation value from the TX Ku-Band frequency. The satellite translation value is 2300 MHz
Transmit Ku-Band Frequency - Translation = Receive Ku-Band Frequency
MHz MHz = MHz
Next – Subtract the LNB LO frequency from the Receive Ku-Band Frequency to determine the correct Receive L-Band Frequency
frequencyIF = frequencyRF – frequencyLO
frequencyIF = MHz MHz
frequencyIF = MHz

12. BUC Indicators/Alarms
There are three LEDs on the BUC
PWR (Power) Green – Indicating Power present
Tx (Transmit) Yellow – Indicates BUC RF PA is ON
FLT (Fault) Red – Two possible states: On – steady Flash – two flashes every second

13. BUC Fault LED (NOTE HiSeasNet does not have any redundant systems)
OFF No Faults or latched faults present.
ON Fault Condition exists
Over Temperature (>90ºC)
Fan Fault
PA Fault
LO Fault
Output power below set threshold
Hardware/software incompatibility
Flashing Primarily used in Redundant Systems to indicate:
* LNB Fault
* Redundancy Controller Fault
(NOTE HiSeasNet does not have any redundant systems)

14. Codan L-Band LBUC BUC Command List – 69xx HLP
General Help (this Display) HLP
Help for Set Commands HSC
Help for Output Commands HOC
Help for Reset Commands HRC
Help for View Commands HVC
HSC
Set Transmit On STOn n=0: Off, n=1: On
Set On Line SOLn n=0: Off-Line, n=1: On-Line
Set Compensation Freq SCFn 13750<=n<=14500, 950<=n<=1700, n=0: Wideband
Set Transmit Attenuator STAn n=0, 4, 8, 12
Set Tx Alarm Threshold SATn 16.0<=n<=33.0, n=0: Disable
Set Burst Threshold SBTn 16.0<=n<=33.0, n=0: Disable
Set LO Frequency SLOn n=15450
Set Transmit Default STDn n=0: Transmit Off, n=1: Last State
Set Redundancy Mode SRMn n=0: Non, n=1: Warm, n=2: Hot
Set Serial Interface SSIr,l,p,s,t (Rate, Len, Parity, Stop, Term)
Set Packet Protocol SPPn 0<=n<=4
Set Packet Address SADn 1<=n<=126
Set Echo SECn n=0: Echo Off, n=1: Echo On

15. Codan L-Band LBUC BUC Command List – 69xx (cont) HOC
Output Tx On OTO Output On Line State OOL
Output Tx Frequency OCF Output Tx Attenuator OTA
Output Pwr Alarm Thresh OAT Output Burst Threshold OBT
Output LO Frequency OLO Output Tx Default OTD
Output Redundant Mode ORM Output Serial I/face OSI
Output Packet Protocol OPP Output Packet Address OAD
Output Echo OEC Output System Status OSS
Output Fault Status OFS Output Latched Faults OLF
Output Status Poll OSP Output PA State OPA
Output Burst Power OBP Output Power Output OPO
Output Temp of BUC OTB Output IF Compen. Freq OIC
Output Identity Data OID Output Max/Min Temps OMT
Output Protocol Data OPD Output Limit Data OLD
Output Device Type ODT Output Build Standard OBS
Output BUC Config OBC

16. Codan L-Band LBUC BUC Command List – 69xx (cont) HRC
Reset BUC RST Reset Change Bits RCB
Reset to Default Values RDV Reset Latched Faults RLFHVC
View System Status VSS View Fault Status VFS
View Limit Data VLD View Protocol Data VPD
View Operational Data VOD View Build Standard VBS
View Identity Data VID