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Service Providers >> Satellite Connection in Africa >> Problem with Nera Satlink Modem https://www.satsig.net/cgi-bin/yabb/YaBB.pl?num=1206447372 Message started by papayeya on Mar 25th, 2008 at 12:16pm |
Title: Problem with Nera Satlink Modem Post by papayeya on Mar 25th, 2008 at 12:16pm
Dear Eric, All,
I 've a nera modem installed and the Rx and the Tx is locked, but there is no intenret link. I checked with my Provider "Telenor", and they said we are not able to see you perfectly, note that my values is almost perfect, not that only, i am able to logon and establish a two way link, then how come they can't read my values. Also when i type the command to show us the Rx valus most of the times this line appears with different values each time: Viterbi Error Rate: 1.668 E-5 and some times it is higher? can that be the problem ? I changed the BUC and LNB and Cables, Network Cables, everything except the modem coz i don't have a spare modem. Also there is a C-Band antenna 2 m far from the Ku Antenna, and no Walki Talki antenna and no GSM antenna. I am confused if i am logged on and the two way link is established how come i am not able to receive internet? My Satellite is Intelsat 1002 Spot 2 - Ku-Band Find below my modem output: # ip show Interfaces If IPAddress SubnetMask BroadCastAddr MTU Alias AdminStatus 1 10.7.4.97 255.255.255.224 10.7.4.127 1500 eth0 1 2 N/A N/A N/A 4074 air0 1 3 10.8.7.45 255.255.255.255 10.8.7.45 4074 dvb0 1 Interface Statistics ------------- Input ----------------- ------------- Output ---------------- If UCast NUCast Disc Octets UCast NUCast Disc Octets 1 123 119 11 25291 6 27 1 2948 2 0 0 0 0 0 0 0 0 3 0 0 0 0 123 0 0 10074 IP Receive Deliver Errors Discards Forward Request NoRoute Discards 452 97 108 6 123 30 0 0 Routing Table DestMask RouteMask NextHop If 0.0.0.0 0.0.0.0 10.8.7.254 3 10.7.4.96 255.255.255.224 0.0.0.0 1 10.8.7.45 255.255.255.255 0.0.0.0 3 # dvb tx show Satellite (DVB) TX Configuration -------------------------------- Auto start : Disabled Population ID : 4 IDU output power : -12 dBm Default CW Frequency: 14.379000 GHz AAL5 Encapsulation : VC MUX DVB Transmitter Status ---------------------- State : On IDU Output Power : -12.2 dBm Eb/No : 6.5 dB delta T : 248338 microseconds Frequency Correction : -110 Hz # dvb rx show Satellite (DVB) RX Configuration -------------------------------- Auto start : Disabled Frequency : 11.606750 GHz Symbol rate : 13.356729 Msps Satellite (DVB) RX Status -------------------------------- Rx State : Forward link up Frequency : 11.609299 GHz Symbol Rate : 13.356700 Msps FEC Code rate : 7/8 SNR : 5.4 dB Viterbi Error Rate : 3.2663 E-4 # odu show Antenna Configuration --------------------- Type Channel Master Type 184 - 1.8m Tx Gain at 14.25 GHz 47.0dB Transmitter (BUC) Configuration ------------------------------- Type JRC NJT5017F (14.0-14.5 GHz) Local oscillator 13.050000 GHz 24V DC supply On Receiver (LNB) Configuration ---------------------------- Type Invacom SPV-1SM (10.70-12.75 GHz) Local oscillator - High band 10.600000 GHz Local oscillator - Low band 9.750000 GHz Oscillator switching frequency 11.700000 GHz LO Switching mode 22kHz 13/18V DC supply 13V # sw show SW versions -------------------------------- Boot : 7.5.3.5 Current : 9.1.5.66 Backup : 9.1.5.66 Manual SW upgrade settings -------------------------------- TFTP server IP addr : 10.11.112.194 File name : 1.tgz Automatic SW upgrade settings -------------------------------- Activated : No PID : 511 IP address : 224.0.1.59 Port No. : 2001 Licenses for SW options -------------------------------- None |
Title: Re: Problem with Nera Satlink Modem Post by Eric Johnston on Mar 26th, 2008 at 9:24am
I suggest you send all this information to Telenor and ask for their help.
Your receive performance is bad ( SNR : 5.4 dB Viterbi Error Rate : 3.2663 E-4 ). You should see Viterbi Error Rate of more like E-8 in clear sky conditions. Try adjusting the pointing. Alter the azimuth and elevation in small steps, like 1/2 turn of a nut, then measure the BER again and see what is the difference. You may have to make perhaps 10 such adjustments and measurements and it may take 30 minutes to complete this task and get the beam exact centre. If pointing does not solve the problem, check the polarisation angle. You need to calculate it and set it to 1 deg rotation accuracy. If you have this wrong you may be receiving interference from the opposite polarisation which is degrading your signal. If the interfering signal varies from time to time then your BER may vary also. Many carriers are intermittent. Also consider the assembly of the dish/feed/feed arms arrangement. Possible problems are that the feed yoke is not attached at the correct holes in the feed arm, side struts not attached at correct place, so out of focus? Does it look right compared with the documentation pictures ? Dish surface distorted?. Do the crossed fishing line test. If your dish has two short side struts at the rear, from the sides of the dish to the az.el head, then they are there for a purpose - to prevent the sides of the dish being pulled forwards or pushed backwards by the weight of the BUC. The inner end holes are elongated so you can tighten the nuts while a couple of other people pull on the sides of the dish. Adjust till the strings just touch. You should be able to ping to IP addresses in the internet. If you can do this but not access web sites by url name, then you have probably not set a valid DNS address in your PC. Best regards, Eric. |
Title: Re: Problem with Nera Satlink Modem Post by papayeya on Mar 28th, 2008 at 2:14pm
Dear Eric,
The problem was from the NOC, they didn't activate my account, however am still worried about: 1- Signal: I tried with my digital meter to get the best and to eleminate the message: Viterbi Error Rate as i didn't see it before on any nera terminals, but i faild, however the signal is 7.5 db which is good as the maximum i guess is 8.5 db, so baiscly increasing the signal wont remove the Viterbi Error Rate Message. So i tried the plorization, if i turned the BUC left or to the right the singal goes down, so it is in the best position, i don't know how to remove the error message. 2- Electricity: Today when i touched the tripod i felt a small current and i couldn't keep holding the tripod, i don't know from where the current is, can it be from the connectors ? |
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