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Idirect Modem No Network light

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nkast
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Nov 9th, 2009 at 3:02pm  
Hi,

I have a mdem for my remote who has been on the network for long time. It went dead due to rain after that it came back online wthout any network light?
TX and RX both solid green.
What could be possible causes?

Regards
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Scout
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Reply #1 - Nov 9th, 2009 at 8:47pm  
OK, so first thing to do is speak with the network operator and ask them to review the history of the modem prior to the time it dropped due to weather.  They need to look at the Tx power in the nominal condition for the modem (when there was no fade)  they can find this in the history easily.  As you have the Rx and Tx green LED, this means you can receive form the hub but they are not seeing your burst to bring you back online, as you can receive well (indicated by the Tx LED as this only comes on with a good RX chain) you should ask the hub operator to set you Tx power via the probe in iMonitor to a level 2db higher than your clear sky nominal value.  This will give your bursts a good chance to be seen.

It is common for a modem to be brought online and over time as the network grows or things are altered the modem is automatically power adjusted, network operators sometimes forget to review modems that have been online and are being looked after by the UPC messages and when these drop off it is hard for them to rejoin the system.  the NO will be able to bring you back by looking at your historical power values, this should not be a major issue.
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TDMAMike
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Reply #2 - Nov 10th, 2009 at 12:17pm  
I agree with Scout.  Get with your network operator.  Have him determine if your initial power is too low or too high, and if he cannot reel you in (to meet the config'ed UCP) you need to start looking at your BUC and associated uplink IF/RF cabling.....
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Regards, &&&&M
 
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nkast
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Reply #3 - Nov 10th, 2009 at 3:21pm  
thanks. We manged to get the site back in but looks like we need to change some hardware as we are down both on the TX and RX.

Another site i have with similar problem but this one have no RX light flashing, this also went down after the the rain, We check the hardware the voltage chage the ACQ range to 2 million but no luck in getting in back on the network...any advice
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TDMAMike
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Reply #4 - Nov 11th, 2009 at 12:57pm  
No Rx LED (or flashing)?

1. Check pointing and POL

2. Confirm the L-Band center freq in the options file is in fact the correct one.  You would be surprised how many wrong or old opts get loaded into the modem by accident. 

3.  Confirm voltage is enabled on the opt and confirm that voltage is present with a mulitmeter.  You mentioned this above, just wanted to re-emphasize.

Ensure the stability on the LNB RFT in the hub matches what the customer on the remote end is using (unlikely culprit, because even with an inaccurate stability setting you often get an Rx LED). Is there are reason you are adjusting the ACQ parameters?
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Regards, &&&&M
 
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nkast
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Reply #5 - Nov 11th, 2009 at 4:24pm  
Hi,
Mange to get the remote back in with the RX Enable ON so no acquisition rage..infact infinite...do i need to change the LNB...as other sites have 280k....
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TDMAMike
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Reply #6 - Nov 11th, 2009 at 6:44pm  
Rx enable on?  I do not see how that would bring it back in, but who am I to question you.  I could see a WAM command possibly being used, but "RX Enable on" makes no sense.  If there is anyone in the forum who can elaborate on this, please enlighten me.
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« Last Edit: Nov 11th, 2009 at 9:24pm by TDMAMike »  

Regards, &&&&M
 
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Scout
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Reply #7 - Nov 11th, 2009 at 7:42pm  
Mike, I am with you......Rx enable on is purely a command to enable the demodulator, with a standard configuration this should never be required unless the command had previously been issued to turn the demodulator off.

As for the issue concerning the acq range, please use the accurate range for the LNB in use.  if you take the LNB stability value and multiply that by 2 you should get the igure to use, it is not advisable under normal operating conditions to increase this.  it may be under certain instances advisable to increase it if you feel there is an issue, but typically I would not do so, there are usually other reasons stopping the correct acquisition.
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TDMAMike
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Reply #8 - Nov 11th, 2009 at 9:26pm  
Scout wrote on Nov 11th, 2009 at 7:42pm:
Rx enable on is purely a command to enable the demodulator, with a standard configuration this should never be required unless the command had previously been issued to turn the demodulator off.


Thanks...That is EXACTLY what I was thinking.  
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1505
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Reply #9 - Nov 12th, 2009 at 9:21am  
What type of LNB, DRO or PLL?
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YIM  
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nkast
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Reply #10 - Nov 12th, 2009 at 10:14am  
DRO
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Adrian
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Reply #11 - Nov 12th, 2009 at 11:43am  
If you have the LED Rx solid green certainly  you have reception. Anyway, you can check this with iSite  Antena Pointing.
Tx solid green it means that terminal are active in the network and transmision are enable.
But, first of all check the transmision chain: supply voltage for the BUC and 10 MHz reference for it and the component itself.
Ask to your network operator to download again option file with Push UDP with reset (maybe the old option file was corrupted) and after that, the network operator must check with Probe the  burst from the terminal and establish the right power.
Also check if the lat long in option file are right.

Good luck
Adrian
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1505
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Reply #12 - Nov 13th, 2009 at 4:43pm  
Have you tried changing the LNB? I observed this in our network, one of the remotes was having Tx, Rx Locked but no Net, but after replacing the LNB it worked. i.e. everything was OK on Hub side.

Best Regards.
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YIM  
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TDMAMike
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Reply #13 - Nov 13th, 2009 at 8:35pm  
Rx Lock should indicate that the LNB is good!
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Scout
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Reply #14 - Nov 13th, 2009 at 9:14pm  
Rx lock indicates a good Rx signal and the Tx green indicates the correct messages are being received from the PP, I would not suspect LNB with Green Tx and Rx LED
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TDMAMike
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Reply #15 - Nov 13th, 2009 at 10:04pm  
I agree.
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1505
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Reply #16 - Nov 14th, 2009 at 6:57am  
I agree with you all, Tx and Rx stable shows the LNB is OK, but the LNB could be faulty leading to the Remote not acquiring into the network (Net LED) or sometimes the Remote could take long time to acquire into the network. I stand to be corrected.

Regards.
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YIM  
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satcom_Frank
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Reply #17 - Nov 15th, 2009 at 6:13pm  
Not saying it could not be an LNB problem, but like a couple people stated a solid RX is an indication that your LNB is good.  As is the solid TX, as that will not come on without recieving the bursts from the Hub.

Rx enable on, is just a command used after doing a CW test.  Obviously you cannot do a CW test while having RX lock as it will never take the new freq, it will always go back to the one in the OPT file.

Rx enable on actually will do nothing for you if I am not mistaken as you already have Rx lock.

If Rx enable on, fixed your problem then any chance you power cycled something else before/during or after you typed the command?  Something else in your Tx path might have had some sort of hang up.
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