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Problems in Afghanistan

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trofkahr
Ex Member


Dec 21st, 2008 at 2:35pm  
Hey Folks,

I'm currently in Eastern Afghaninstan and just switched providers (Skylogic to a Kabul based company called AFSAT)

Both providers appear to be using the same sat  (AM22)  just different frequencies.  We swapped out LNB's (skylogic LNB = NJR2154HA - AFSAT LNB = NJR2184F) and used a spectrum analyzer (and a horizon finder) to auger the dish in based on the azimuth the provider gave us.

At the moment, we seem to be on target with the dish.  That said - we have no satellite light at all on our modem. 

Our pconf looks as so:

pconf
KSET BootConf
  Item 1. Addr 21d728, Key 0 0x0 ItemMark 1 ArrayPos 0
    termid                   0xce2c    popid                 0x11e0002
    ctlPID                   0x1029    pcrPID                    0x365   
    TDMCarrierFreq          1154750    SymbolRate             18889000
    MaritimeEnabled               0    Latitude                      0   
    Longitude                     0    TxPower                     -20   
    ODUStatus              INTERNAL    VCXOPar1                    0x0   
    VCXOPar2                    0x0    TimingLoopBW                0x0   
    Signature                   0x0    isEncryptionEnabled           0   
    isRnccKeyValid                0    isRcstKeyValid                0   
    PointingTool                  0    LNBVoltage                    0   
    LNBVoltageIncrease            0    LNBToneOn                     0   
    DVBMode                   DVBS1

The TDMCarrierFreq / POPID / SymbolRate / TXPower were all provided by AFSAT.

We're at a loss - and quite admitedly *not* satellite experts. 

One thing we *have* noticed is that when the modem in question reboots and POSTS - the Alarm and Sat lights simply blink for a brief second and then go dark.

On our other system (the working one) - when the modem POSTs - all the lights light up and stay lit together for a brief time.  The Alarm light will go out - and the Sat light will start to blink as it aquires and locks on.

The provider is trying to be helpful - but their english is only slightly better than our Dari...which is to say - not much communication is going on.

I know how to telnet into the modem and check tcmp / pconf - as well as how to configure the boot parameters.  Beyond that though - it's all a learning experience for me.  The provider basically send us a cut/paste of one of their other customers bootconf and said "make it look like this one."  I checked the LinkStar guide and found which values you can change using savebootparam and which are set by the factory.

Assuming we have the dish pointed correctly - I'm worried that our modem may have failed in some way.  Is there something we can do to verify this?

Can anyone offer any suggestions as to what to look at next? 


Thanks
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Eric Johnston
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Reply #1 - Dec 21st, 2008 at 4:01pm  
On your spectrum analyser you should see your wanted carrier at frequency = 1154.750 MHz and approx     18.889 MHz wide.

If you can't see your wanted carrier you are on the wrong polarisation, wrong satellite, wrong LNB or your tuning information is wrong.

I am presuming you have set the polarisation by starting with the LNB either at the side or at the top and have then applied approx 20 deg clockwise adjustment, while facing towards AM22 satellite,  Try looking at the opposite polarisation by turning the feed a further 90 deg.

AFSAT should have told you the polarisation starting position.  Horizontal means start with LNB side arm upwards.  Vertical means start with LNB side arm out sideways.  Then apply the +20 deg clockwise adjustment.

Best regards, Eric.
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trofkahr
Ex Member


Reply #2 - Dec 22nd, 2008 at 4:32am  
roger that - 1154.750 - we've got the shot then.  The LNB's are the same LNB's the last unit here used while on AFSAT.

My bet based on your response is that we have the polarization hosed up.  Nothing was provided by AFSAT.  I'll dig in that direction and hope I hit China.

Thanks again.
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trofkahr
Ex Member


Reply #3 - Dec 22nd, 2008 at 6:30am  
Eric,

thanks a ton - gave the bloody thing a twist and suddenly we're talking.

It's always the simple stuff.
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trofkahr
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Reply #4 - Dec 23rd, 2008 at 11:39am  
Okay - new twist.

Our modem's sat light will blink slowly for 2 minutes or so.  During this time our QPKSBER is around 0.0001 or 0.00009.

After 2 minutes - the sat light blinks off and stays off until the modem recycles at the 5 minute point.

Same thing - sat light pops back on.

According to AFSAT - Germany can't see us on clean carrier.

Any suggestions?
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Eric Johnston
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Reply #5 - Dec 24th, 2008 at 12:12pm  
1. Could be error in the popid  ctlPID  pcrPID.  Check with your service provider.

2. Could be too high or too low transmit level setting.  Tell your service provider the length of your tx cable and follow their guidance.  The config number is in 0.5 dB steps.  For normal operation the input level to the BUC must not be too high or too low.  Too high and the BUC is overdriven (and possibly damaged) and the tx signal is distorted and won't be received properly at the hub.  Too low and the modulated signal won't be high enough to be received at the hub.  In clean carrier mode an extremely very low level will be detectable at the hub spectrum analyser.

3. Could be your BUC is not connected.  Check the cable F type terminations. The outer braid making contact ?.  The inner pin sticking out 2mm beyond the rim and actually going into the socket hole.  Turn the mains power off before working on the coax cables and under no circumstances get the cables crossed over or short circuited.

4. Does the hub know your MAC address correctly ?

The installation manual has a diagnostic flow chart and quite a lot of details relating to the above particular situation.

Happy Christmas, Eric.
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trofkahr
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Reply #6 - Dec 26th, 2008 at 10:18am  
Thanks Eric - I've downloaded the install flow chart and have been going through it.

Your comment about the tx setting has me a bit worried.  We're probably running about 50 feet or more between our dishes and the modem. 

AFSAT has yet to provide us with the hubs install guidelines.  Their only guidance was to copy someone elses pconf and shoot the information to us and say "make it look just like this..."

I'd hate to have burned our buc up by starting out with too much tx power.

Cabling looks good - and was working fine with our old provider.

As far as registration with the hub - I am assuming they got that right.  I have checked the MAC we sent and it is correct.  Whether the hub recieved it correctly from AFSAT - or whether the registration process is complete I have no idea.  AFSAT has taken great pains to tell us they're billing us as of the 18th - so either they're running a number on us - or it's registered and we have a different problem.

I've asked for the hub's NOC contact information and been completely ignored.

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Eric Johnston
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Reply #7 - Dec 26th, 2008 at 11:17am  
If the transmit level is -20 then don't worry about the BUC.  -30 might be a bit safer.  Numbers like -10 or 0 might cause damage.
The input level to the BUC for maximum output is probably -20 dBm and you will get this with a setting of -30 on the modem and 5 dB cable loss.   -30 * 0.5 = -15 dBm out from the modem.  -5dB cable loss = -20 dBm into the modem.  The final level setting needs to be done carefully.  The hub can adjust in 0.5 dB steps, increasing it from a low level till there is no further improvement and then backing it off by 1 or 2 dB.  This sets the maximum level that should ever be used during normal operation with a modulated transmit carrier.
If the initial level is far too low (not as in this case) then the modulated bursts from the remote will not be receivable at the hub.  If the initial level is far too high the BUC sends out a broad band of distorted noise which is not receivable and will also interfere with uplinks from other sites.

The service provider should have given you a single text configuration line to type in.  Something like this:
save -t <TxPower(0.5 dB steps) > -f <TDMCarrierFreq> -pop <popID> -s <SymbolRate> -c <ctlPID> -pcr <pcrPID> -o <ODUStatus> -lnbv <0|12|13|18|20> -lnbi <0|1> -poi <0|1>

I don't like the idea of telling you to set the pconf the same as some other site as the pconf is an output display that contains some things that should not be changed.  For example, you should not try changing the site ID to match another site.

If you type in tclgets does it say PCR=true ?  If PCR=true, I believe that this will confirm you are on the correct satellite.

You really need to chase AFSAT to help you, as the actual hub service provider may be unwilling to talk to end users.  I am always annoyed by this attitude as in my experience if the end user can talk to the person actually at the hub computer screen who can simultaneously see a spectrum analyser then  problems are resolved quickly. The hub can also verbally guide your hand adjustment of the polarisation angle to the exact null.

Best regards, Eric.
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« Last Edit: Dec 26th, 2008 at 9:04pm by Eric Johnston »  
 
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trofkahr
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Reply #8 - Jan 3rd, 2009 at 5:40am  
well - after every thing was said and done - AFSAT hadn't registered the MAC with the NOC.  I managed to get the NOC's contact info and went through their technical support. 

System is up and it's flying.

Now the fight to get our billing adjusted based on the *real* start date.

Thanks again for the help - we most likely wouldn't have service up if it werent' for your assistance.
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imNAK
Ex Member


Reply #9 - Jul 23rd, 2010 at 6:22pm  
hello ,
i from AFSAT comm.. i read your post .. its too late but any way
the new values for the modem
as
We would like to inform you that the values for our S1 and S2 HUB will be changed after the today maintenance.

The NEW configuration-string for S1 is:
save -pop 0x11e0001 -c 0x1029 -pcr 0x365 -f 1145160 -s 4681480 -o 1 -t -24 -dvb 0

The NEW configuration-string for S2 is:
save -pop 0x12e0001 -c 0x1029 -pcr 0x365 -f 1183925 -s 20125000 -o 1 -t -24 -dvb 1

In case the new parameters are not configured automatically, you must give them manually.

thanks
Noor Ahmed
www.afsat.net
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« Last Edit: Jul 23rd, 2010 at 8:02pm by Admin1 »  
 
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