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SCPC RX ERROR ??!

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Oct 10th, 2008 at 4:59pm  
Dear All,

We have some remotes in our hub which give the following error

[img]http://filaty.com/i/810/34715/10-10-2008_6-36-02_PM.png[/img]

Any idea what this could be?

iDS Software: 7.0.5
Remote: 3100
Circular Polarization
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Reply #1 - Oct 10th, 2008 at 8:52pm  
nice to see hub engineers not knowing how to work the the system

i wonder about the guys at XXXXXXXX... hmm
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« Last Edit: Oct 13th, 2008 at 7:25pm by N/A »  
 
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Reply #2 - Oct 11th, 2008 at 9:02am  
There are lots of reasons for the SCPC RX errors.
It is to do with the RX chain.
If the issue is at the HUB's end then you will see these errors on ALL the remotes, in such a case check with the satellite operator.
If you see the errors for few remotes then the possible causes are,
1. Low Downstream C/N i.e rx snr.
2. Bad LNB, filter
3. Bad cable connectors
4. Any bad equipment on the receive chain
5. Interference at remote end.

Good Luck,
Raja Praveen
Bentley Walker LTD.
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Reply #3 - Oct 11th, 2008 at 12:05pm  
Dear cylent,
Thank you for your reply, I just receive no training yet to manage a Hub, and it's a new system to me, kindly accept my unenlightenment, that's why I was here in the first place.

Dear ShareUrKnowledge (Ture Nick Name)

Thank you very much for your detailed answer. We were always think it's something related to the TX ! and for that, we tried to change the Tx Power several times with no luck. it's totally appeared now we were working in the wrong chain.

I will pass this information to our technician on site to make sure he will check all the equipments you mentioed above and feed you back with the result. Thank you sir.
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Reply #4 - Oct 11th, 2008 at 5:01pm  
Dear Y2J...

1- How many Remotes that gives you that error?

2- Are most of those Remotes are in one Area or near

each other?

3- before the upgrade to 7.0.5 when you were working

with 6.9 version did this error ever show before ?

BR...
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Reply #5 - Oct 13th, 2008 at 1:18pm  
Dear Ashraf,

1 - The numbers of the remote is not fixed, it's change form one time to another. You may say between 5 to 6 remotes..

2 - No, There are in the different locations.

3 - We did not apply any upgrade and our hub is running iDS 7.0.5 since we lunch it.

I hope that can help you make any picture about what the wrong could be.

I have send the above information from Mr. Raja to our engineer on site and awaiting his feedback.
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Reply #6 - Oct 13th, 2008 at 2:30pm  
Quote:
There are lots of reasons for the SCPC RX errors.
It is to do with the RX chain.
If the issue is at the HUB's end then you will see these errors on ALL the remotes, in such a case check with the satellite operator.
If you see the errors for few remotes then the possible causes are,
1. Low Downstream C/N i.e rx snr.
2. Bad LNB, filter
3. Bad cable connectors
4. Any bad equipment on the receive chain
5. Interference at remote end.

Good Luck,
Raja Praveen
Bentley Walker LTD.

Rather than focus on the remote end, I would look towards the IF/RF uplink chain (cabling, hardware, sky conditions, etc) at the teleport earthstation.  Especially, if the errors are observed on multiple terminals in different geographical locations. <---that is an important piece of information.

The common denominator amongst all of those remotes is their downstream carrier (the Hub uplink)....so it is doubtful that all of the remotes have an Rx problem.  
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« Last Edit: Oct 13th, 2008 at 7:26pm by N/A »  
 
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Reply #7 - Oct 13th, 2008 at 4:07pm  
I think its very amusing when the response from the So-Called Trained hub "Engineers" use the interference excuse.

I guarantee the problem is hub side in fact i'll bet money on it.

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Reply #8 - Oct 13th, 2008 at 6:04pm  
Paul, interference is not really such a rare event and may really be the cause of those errors, especially if only a single remote exhibits such behavior. 

This is a satellite connection system. It uses radio waves like many other wireless devices to communicate. I've heard some funny stories about such problems, for example some guy complained that every day 5pm the Internet was down. Worked like a clock. That was interference. After extreme troubleshooting sessions the reason was determined - the lawnmower that was used every day had motor sparkling and creating tremendous amount of interference on the system.

Another funny occasion (not an interference case but still..) I had with our own customer in Africa. They also complained the system was down every day in the evening, worked like a clock also. After extensive troubleshooting we found out that the automatically rotating lawn sprinkler has been adjusted to sprinkle on the antenna at the fixed time, every day.
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Reply #9 - Oct 13th, 2008 at 6:17pm  
Agree with Maxim.  If the observed error (SCPC error) is on single remote then naturally that drives an entirely different troubleshooting approach (and very well could be local interference on the remote end).  However, in this case the problem is observed by numerous remotes, therefore the problem is more than likely on the hub end.
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« Last Edit: Oct 13th, 2008 at 10:28pm by N/A »  
 
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Reply #10 - Oct 13th, 2008 at 7:32pm  
Fine.

I believe Maxim.
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Eric Johnston
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Reply #11 - Oct 13th, 2008 at 10:38pm  
Some more examples of downlink interference, unique to one receive site:

Security guard patroling and reporting in using hand held two-way radio.
Bus door drive motor at nearby bus stop.
Radar from particular passing ship (regular service).
Particular car arriving and leaving nearby car park.
Adjacent satellite interference on downlink due to out of focus dish.
C band interference due to new wireless services also operating in C band.
Interruption of signal due to aircraft blocking the beam.
Interruption of signal due to nearby crane activity.

Best regards, Eric.
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Reply #12 - Oct 15th, 2008 at 9:56am  
Dear All,

I am really thankful for the rich information and sharing of the experience including the trouble-shooting stories, which are very helpful to our conditions we found here.

Our engineer on site indicated that the LNB Filter is not good and we may need to replace it. We shall send a new Filter and check again.
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Reply #13 - Oct 15th, 2008 at 11:49am  
Hub side? Remote side?

I thought this problem was observed on numerous remotes (more than 5 as you said above)?

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Reply #14 - Oct 16th, 2008 at 1:32pm  
The LNB Filter for the remote site.
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Reply #15 - Oct 16th, 2008 at 1:44pm  
"The LNB filter at the remote site"

An interesting suggestion.  If the remote site BUC is being driven too hard the output may be spashing all over the place and interfering with the LNB and thus outlink reception.  I would however expect such interference to occur every time the remote transmitted.

Another thought is the coax cables.  When the BUC transmits its DC supply current increases and if there is poor connections in the BUC braid then bursts of current get superimposed on the LNB supply causing brief anomalies in the receive signal.

Best regards, Eric.
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Reply #16 - Oct 16th, 2008 at 2:45pm  
hi Y2J,

it is an error on RX cable or LNB from the remote side.. if you are getting SCPCRx Errors below 100 there is nothing to worry about,but if it is getting 10,000 and higher then you need to check the cable, connector and LNB.

Best Regards,,
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Reply #17 - Oct 16th, 2008 at 9:39pm  
What is puzzling to me is that the thread originator stated that the SCPC errors were observed on MULTIPLE (5-6) remotes in the beam.  

Unless these remotes are in very close in proximity to each other, I would think that the likelihood of the problem being on the remote is low.  Especially if the errors are observed by 5-6 remotes in the beam.  Unless I am missing something?
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« Last Edit: Oct 17th, 2008 at 3:48pm by N/A »  
 
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Reply #18 - Oct 17th, 2008 at 3:20pm  
TDM ...
Am with you in your question!!! what i understood from the begining that its a common problem in more than one site !!! so i think Y2J you need to explain this a little bit , can you ?? also what i understood from theorginal post that the Error message in on the HUB side not the remotes sides, if it like this then how come forthe problem to be from the filter of the LNB which is the reciving side ob the remotes not the HUB !!! am totally lost here.
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Reply #19 - Oct 17th, 2008 at 3:50pm  
If it were me, I would be looking for energy under that outroute (fwd carrier).  This issue smells of a small spike under the forward.  That or a faulty cable in the uplink IF/RF chain.
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« Last Edit: Oct 19th, 2008 at 5:34pm by N/A »  
 
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Reply #20 - Oct 17th, 2008 at 5:21pm  
Dear TDMAmike,

i doubt it could be faulty cable in the uplink IF/RF chain,because if it's so that means all the remotes should have the same error not just few of them (5-6).
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Reply #21 - Oct 17th, 2008 at 6:54pm  
I will buy that, but he never did say just how many remotes are in the network.  The statement leads me to believe there are more than just 5 or 6.
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Reply #22 - Oct 17th, 2008 at 7:46pm  
Quote:
Dear Ashraf,

1 - The numbers of the remote is not fixed, it's change form one time to another. You may say between 5 to 6 remotes..

2 - No, There are in the different locations.

3 - We did not apply any upgrade and our hub is running iDS 7.0.5 since we lunch it.

I hope that can help you make any picture about what the wrong could be.

I have send the above information from Mr. Raja to our engineer on site and awaiting his feedback.

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Reply #23 - Oct 17th, 2008 at 8:05pm  
Dear Mike/Ashraf,

As I said above, the Remote sites are not fixed. the error did appear in some remotes (5 to 6) and sometimes it's remain in 2 to 3 remotes only, and sometimes only in one remote.

Ashraf,
The error appear in the iMonitor software which is run by the HUB site/people, that's why we saw it since the iSite don't provide such information.

Dear Taan,

Thanks a lot for your sharing. Yes I checked the error message and it has variable numbers but they are all under 10.000.

I will be happy to provide any information to all of you to fix this problem, not only for me, but to make it as a trouble-shooting guide for all who face such an issue. Thank you All.
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Reply #24 - Oct 18th, 2008 at 12:30pm  
If the receive errors at the remote sites occurred at particular times of day at particular sites it may be possible to show that they were all caused by the recent autumn equinox sun conjunctions.

Also note that all the remote sites are liable to lose return link connectivity simultaneously, when the hub receive path is affected.

Best regards, Eric.
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