THE UNIVERSAL RF INSTALLATION GUIDE

Transcription

1 THE UNIVERSAL RF INSTALLATION GUIDE Released in January 2010 By: AFSAT SERVICES LIMITED AIS HANGAR, WILSON AIRPORT, LANGATA ROAD P.O. BOX 27554, NAIROBI, KENYA. 1

2 Abbreviations BUC LNB OMT LO IF SSPA Block UP Converter Low Noise Block Downconverter Ortho Mode transducer Local oscillator Intermediate Frequency Solid state power amplifier Background The radio unit is made up of the Feed horn, OMT, LNB and BUC. Feed Horn In VSAT antenna, the feed horn collects the downlink signals that are focused into it by the reflector. It also launches the transmit waves in a wide spray towards the antenna reflector which then focuses them into a narrow beam. OMT (or combiner and/or Polarizer) The combiner connects to the feedhorn and separates the transmit and receive signals going to and from the LNB and BUC respectively. BUC The Block up-converter, accepts the transmit IF signal from the modem, translates it to the uplink frequency (e.g KU-band) and amplifies it with an internal SSPA to a higher power level. LNB The LNB (Lownoise block downconverter) amplifies the extremely weak downlink signal from the antenna. It also converts the receive signals in a block covering the entire satellite band down to a frequency in the 1Ghz to 2Ghz range. This is done to permit the use of a long inexpensive cable to deliver the receive signal to the indoor unit. LNB s are made in various frequency bands and performance levels. The Universal LNBF A universal LNBF (Low Noise Block downconverter with integrated Feedhorn) was developed to address the need to tune several sections of the KU FSS band with a single LNBF. They will tune MHz and they have two separate local oscillators at 9750 and MHz, which will allow the LNBF to tune a large expanse of the spectrum. The receiver uses a special signal to tell the LNBF which of the local oscillators it should use for the frequency it needs to tune. 2

3 When the lower frequency set is needed it uses the lower frequency LO, and when the higher set is needed it uses the higher LO. There has to be an automated way for the receiver to tell the LNBF which LO it needs, so the universal LNBF uses a 22 Khz signal. When the receiver sends the 22 KHz signal the LNBF uses the higher LO, and when it doesn't it uses the lower LO. The receiver is usually preprogrammed with a "switch" frequency, so that when setting up the particular satellite, if "Universal" is selected as the LNB type, and a frequency above MHz is selected, it turns on the 22khz signal so the LNBF will use the correct LO frequency, and if it's below MHz, it turns the 22 Khz signal off. Figure 1: The universal LNBF 3

4 Figure 2: The complete RF Using the universal LNBF The Part number of the universal LNB that shall be used is NOTE 1: The universal RF shown in Fig. 2 above is used as a complete unit. This therefore means that the universal LNB SHALL NOT be used as a direct replacement of the standard LNB in the ordinary RF unit. In order to use the universal RF on the iway network, the installer MUST select LNB type AFSAT_UNIVERSAL from the LNB type pick list present on the modem configuration page before commissioning. This relies on the presence of an LNB pick list in the sbc.cfg file of the modem s flash file system at the root directory /cfg0/. The modem presents a simple GUI which presents a predefined pick list of LNBs to the installer. As long as the pick list in the sbc.cfg is configured correctly for the given network and the installer picks the LNB in use, the tuning delta is calculated and remembered and the VSAT will operate on all transponders of a satellite knowing how to translate any frequency without further intervention. 4

5 The procedure below details the process of upgrading the modem s Satellite Based Commissioning configuration file sbc.cfg in order to obtain the required LNB type from the LNB pick list. NOTE 2: Prior to upgrading the configuration file, confirm that the modem is running on the following versions of fallback.bin software. Contact Afsat for guidance on software upgrade if this is not the case. HN7000S fallback.bin release (built Oct 17, 2008, 14:23:44) HN7740S fallback.bin release (built Oct , 10:11:23) STEP1: Ensure that you have the required Satellite Based Commissioning configuration file sbc.cfg from AFSAT. This file may be downloaded from the iway Africa Support portal; Download and save the file in your PC. STEP2: Configure your PC LAN port with IP address range of the modem e.g; IP Address Subnet Mask Default Gateway STEP3: While connected to the modem, open your browser and on the address bar type; LAN1 IP ADDRESS/fs/advanced/advanced.html and press ENTER. A page like the one in Figure 3 below appears. 5

6 Figure 3: Modem advanced page STEP4: From the Installation Menu double click on Setup to open the setup page shown below. 6

7 Figure 4: Setup Page 7

8 STEP5: Double click on Config File Upload from the menu on the left hand side of the Setup page above. This should lead you to the page shown below. Figure 5: Configuration File Upload Page STEP6: Press the Browse tab on the File Upload page above to select the location that sbc.cfg file has been saved in your PC and then press Upload. The modem will show the page shown below as a confirmation that the file has been successfully uploaded. 8

9 STEP7: Close the confirmation page above and go back to the Setup page shown in Fig. 4. Now open VSAT Manual Commissioning from the menu. Under the Radio Parameters menu, select Receive LNB type AFSAT_UNIVERSAL from the drop down menu. This is illustrated below. 9

10 STEP8: Save the configurations. The page below will appear as a confirmation that the configurations have been saved. STEP9: The modem will now be ready for use with the universal LNBF once it reboots. When the modem restarts, configure with the parameters obtained from AFSAT and commission in the normal way. End 10