Satellite Internet forum
VSAT technology and installation >> Dish pointing and alignment >> Strange problems aligning with idirect

Message started by shinnix on Jun 17th, 2007 at 1:31pm

Title: Strange problems aligning with idirect
Post by shinnix on Jun 17th, 2007 at 1:31pm
Strange thing is happening while trying to point my antenna.  1.2M dish, crosspol feed, iDirect 3000 with 7.1.1 firmware and iSite, trying to point to W6 from Iraq.

I used a handheld terminal to align the antenna to W6 Eutelsat.  I then disconnected the terminal from the lnb, and reconnected the Rx cable to the modem and powered on.  Using the antenna pointing GUI in iSite, I saw nothing (0.3v), rx snr -1.00.  

Doubting the handheld terminal, I pointed it manually using only iSite antenna pointing.  I acquired various signals, but none would give me a reading above 8V rx.  Regardless, I would lock the antenna in place, and try rx snr.  Nothing.  Eventually, I determined the pattern of behavior.  I figured out that once I acquired any kind of signal, the moment I exited and restarted the iSite software or the telnet session, it would not display any signal.  Even if I put my hand in front of the feed horn, it registered nothing (0.3v).  Rebooting the modem did not help.  The only way i could get it to appear to function again was to repoint the antenna AWAY from the signal, to a random spot.  Only then could I put my hand in front of the feed horn again and register voltage, and only then could I move the antenna around again and detect signals.

Has anyone ever seen this before?  I'm not an expert, but I'm also not completely new.  I set up four other sites in Iraq using iDirect 3100 and 5000-series modems, and never had this problem.

At this point I'm thinking it could be the option file.  I've reflashed the firmware and re-pushed the option file several times, but is it possible that certain parameters in the option file are the root cause?

Title: Re: Strange problems aligning with idirect
Post by Broadwave on Oct 1st, 2007 at 8:56am
I am having the EXACT SAME PROBLEM and it is driving me insane.  Please tell me you have resolved this issue.  Were you ever able to figure out what is going on?

Title: Re: Strange problems aligning with idirect
Post by Eric Johnston on Oct 1st, 2007 at 12:19pm
I've sent an email to iDirect drawing their attention to this problem, so maybe we will see a reply here.

It would seem to me that the LNB power is somehow getting turned off, and staying off, even after a reboot. If you have a T connection in the LNB cable it would be interesting to note if the failure to detect any noise power at all (e.g. a warm hand or any satellite) is associated with no LNB supply voltage.

What LNB power options are there in the options file? e.g. 13 or 19 volts and 22 kHz tone on / off etc. ?  I am interested because we now do a 5 watt universal Ku band TRIA with LNB co-pol / x-pol and low /  high Ku band, all integrated in one TX/RX integrated assembly.  For modems without the full 950 - 2150 range there is an indoor dongle for the LNB cable that allows any of many LNB LO frequencies to be selected with DIP switches.

Best regards, Eric.

Title: Re: Strange problems aligning with idirect
Post by Oasis Networks on Oct 1st, 2007 at 12:41pm
As far as I know, the isite pointing tool doesnt show absolute values but relatives (at least at versions 6.x), this is why when you first open it it will always start at the bottom, even if you are on the satellite.
That could be a reason for this behaviour.
If this is indeed the case, just mark with a marker the position on the dish and move it away and start again.

And again...why wouldnt you contact your service provider about it?

Title: Re: Strange problems aligning with idirect
Post by Broadwave on Oct 1st, 2007 at 4:34pm

It is not an LNB problem.  After testing with another idirect modem, it does not experience this issue.  It works as it should.  Every time you reboot the modem it will show the correct signal.  I don't know what is going on with the other modem, but it appears that it is not working correctly.

Both modems are running the same version: with the same options file (although one modem is a 5150 and the working one is a 3100, the options file had to be adjusted for the different modem types and serial #s)

We have taken it up with our service provider.  They have never seen the problem.

We now have 16V on the 'working' modem and are attempting to crosspol.  Hopefully all will go well.  I appreciate the responses.  

I will be VERY interested to see what idirect has to say regarding this issue.  Thanks for contacting them.

Powered by YaBB 2.5.2!
YaBB Forum Software © 2000-. All Rights Reserved.