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First time Satellite install - LinkStar

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Ex Member
Ex Member

May 5th, 2006 at 8:05am  
Hello. I purchased service/equipment through thuraya.pl. I have been trying to get the dish pointed with no luck. After playing around for the last 3 days I am getting pretty frustrated and hope someone can help.
I Still have not been able to lock on to the NSS 6 satellite.
My QPSKBER number is still between .100 and .130 and SAT light has never come on.
I tried unplugging the cables from the back of the modem and the number did the same thing. I thought the cables might be bad so I replaced them. After replacing the QPSKBER number did the same thing. Also, our MaxTimeSynced has never changed from zero.

From reading information on the internet it seems that as long as we are even close to the satellite we should recieve some sort of signal? Is that correct?

Is there any way to reset the modem so we can put in our parameters again?

Also, the modem seems to reset it self everyonce in awhile while I am logged in and using the TCMP command. Does that seem normal?

I have a newer 10.2.x.x modem

Is there some place I can download the Modem instruction book? Not the install guide...

Thank You

Here's some more questions:
using https://www.satsig.net/ssazelm.htm I get a Magnetic azimuth of 110 and a elevation of 23.9. Does the offset of our dish (22 deg) play a factor in the elevation? And if so would we add 22 or subtract 22?

We have the dual optic dish from this page http://www.sepatriot.com/tx1.2ku.htm

We have pointed the dish all around the area that the calculator says and still have never gotten a signal...any ideas? Any way to tell if modem is damaged?

For the linkstar modem does there need to be a ground on either of the cables?
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« Last Edit: May 5th, 2006 at 9:47am by Admin1 »  
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Eric Johnston
Senior Member

Posts: 2109
Reply #1 - May 5th, 2006 at 9:38am  
Using your PC, type in the exact complete line of configuration information.   Do it very slowly and very carefully and don't make any mistake.   The modem will wait for the carrier to appear at the correct frequency etc.

The L band frequency will be the RF frequency minus the LNB LO frequency.  It is important that you have the right type LNB, e.g 10, 11.3 GHz etc.  

Do make sure you have the polarisation angle correct. What nominal polarisation name is your downlink supposed to be called ?  It will be called Horizontal or Vertical.   I assume Horizontal below.   Look at the LNB and work out what is horizontal polarisation.   It is when the wide faces of the rectangular waveguide are at the sides.  Inside LNB waveguide the dipole pin will be horizontal.  This is the Horizontal polarisation starting position.

Now using the output from the calculator, set the required polarisation angle.  If the required number is positive rotate the feed clockwise while facing the satellite.    You can set the amount of angle accurately using an inclinometer held sideways across the waveguide or BUC body etc.  Alternatively wrap a strip of paper round the feed throat and mark the circumference.  Measure the length.  The adjustment distance round required is circumference length x angle /360.  Put the strip back and turn the feed the required angle.  If there is a scale use a magnifing glass to read it.  This angle needs to be set to 1 deg accuracy and the hub may ask you to adjust it slowly by very small amounts while you put yourself under the feed arm.

Regarding cables, the inner wire should stick out 2mm and the outer braid must make perfect electrical contact.  The workmanship must be perfect on all connectors.  This is not a joke.  

Do take great care not to cross over the cables or short circuit the cables.    It will damage the LinkStar modem. I would advise getting the receive aspect perfect before even connecting up the BUC.  This also helps avoid premature commissioning if the hub have set everything up ready.  Turn things on and off using the modem power switch, not by pulling out the IFL cables with the power on - the transients may damage LNB, BUC or modem.

If the dish offset is 22 deg and the required elevation angle 23.9 deg the front face of the dish needs to tilt backwards at 1.9 deg.   Hang a 1.5m long string with a weight in the air in front of the dish and move till it just touches at the bottom.  The gap at the top should be 4.0 cm exactly.  ( 120 cm x tan (1.9) )

Just swing the dish boldly sideways and you will find the satellite on the first swing. The RX LED will flash green.  Peak up by turning nuts 1/6th of a turn and make approx 30 repeated BER measurements and adjustments.  Do the azimuth first, then tighten and finally the elevation.  It should take much longer to do the final peaking up than finding the satellite.

Earthing the antenna mount structure may be a requirement of the local laws, for lightning protection.

Best regards, Eric.
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