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VSAT technology and installation >> Dish pointing and alignment >> aiming idirect to 10-02 in iraq

Message started by kombatgecko on May 14th, 2008 at 6:38pm

Title: aiming idirect to 10-02 in iraq
Post by kombatgecko on May 14th, 2008 at 6:38pm
Ok, im seriously having issues and very beyond losing my mind in how to aim this satellitte.  I initially put the satellitte up and was receiving 8v.  Anyway, im used to using the military vsat which aims itself.  So, the problem, i cant figure out the exact angles.  Any help would be great.
 I was told to set the dish to 241 degrees, to easy, then it said move it 20 degrees to begin to sweep.  So, thats easy.  Next, the elevation should be 28.25, so do i subtract the 17 degree offset? Do i put that offset in the isite software where it asks for offset?  Also, the tilt says 47.26, all other dishes here on post are going the opposite way.  I am in southern baghdad at camp falcon and my location is 33.36 and 44.21.  I have the andrews 1.2 m dish, and the idirect 3100 router.  I can program just about anything, and can make any network work.  However this satellitte is something im not going to let beat me.  Thank you for your help.

Title: Re: aiming idirect to 10-02 in iraq
Post by Eric Johnston on May 14th, 2008 at 8:07pm
Ask your service provider if your receive polarisation should be vertical or horizontal.
Determine your dish pointing angles, azimuth, elevation and polarisation using
satellite dish pointing in Iraq

Setting the polarisation is a two step process:
What receive downlink polarisation name have you been told to use?. Horizontal or vertical.  Set this name initially, using these diagrams as a guide:

If Vertical, the LNB input waveguide will be like the image above. The internal dipole pin may be above or below; it does not matter.

If Horizontal, the LNB input waveguide will be like the image above. The internal dipole pin may be on either side; it does not matter.
Then apply the polarisation adjustment angle. A positive polarisation adjustment means turn the feed clockwise while facing towards the satellite.  A negative polarisation adjustment means turn the feed anti-clockwise while facing towards the satellite.  In some cases the entire dish and feed assembly needs to be rotated using a giant polarisation scale behind the dish (HX and Tooway)

Set the elevation angle:
Use the elevation angle scale if there is one.  If not, find out the offset angle of the dish.  Set the front face vertical, the beam elevation angle is now the same as the offset angle.  Adjust further as required for the wanted elevation angle.   If you don't have an inclinometer then here is how to make an inclinometer.  If you can't find the offset angle put a thin strip of wood under the lower edge of the dish, beside the feed arm. Put the forward end of the strip across the top of the feed horn window.  The slope of the wood is the approximate elevation angle.

You say "28.25, so do I subtract the 17 degree offset"
If the front of the dish is vertical your beam elevation angle is 17 deg.  Tilt the top of the dish backwards by an amount of 11.25 deg.  The front face then has an angle of 11.25 deg (or 78.75 deg).  A strip of wood up the front face or a 'vertical' part of the dish back structure provides a reference for the inclinometer.

Use a compass or the sun and the time of day to get the approx azimuth angle.  With the LNB cable connected, swing the dish boldly and find the satellite.  If nothing change the elevation in 1 deg steps.

Peaking up:
Having found the satellite spend at least 30 minutes peaking up.  You need to get to the exact centre of the beam as the transmit beam is narrower than the receive beams.

Clever tricks:

With the azimuth nuts spaced apart, gently swing the dish to rest against each nut in turn and adjust the nuts so exactly the same degraded quality is observed at each side.  Then wind each nut in by an equal number of turns and flats.

Having centered the azimuth, make sure all hold down bolts are tight.  The elevation is easier as there is no backlash. Wind the elevation screw right across the satellite and then count the turns back to the centre.

Polarisation:  Be prepared to adjust a few deg under verbal instruction from the hub while they measure your CW transmit cross-pol signal.  Keep your head and body underneath and reach up to make this adjustment, so as not to obstruct the beam. Be patient, it may take the hub 20 seconds to take each measurement.

Power off and connect up the transmit cable.

I know little about iDirect so I hope others will help you further here.  I do know that it is very important that you tell the modem, via iSite, what is your latitude and longitude to set the range and timing so that your transmit bursts arrive at the satellite at the correct moment, interleaved with other uplink bursts.

Best regards, Eric.

Title: Re: aiming idirect to 10-02 in iraq
Post by kombatgecko on May 15th, 2008 at 7:04am
Thank you for your help.  Last night i tried for almost 2 hours, started from scratch, releveled and made the adjustments.  I used the isite software, but used the telnet session to get a reading like other have suggested.  I also noticed i hit 5.1v in telnet, but nothing in isite.  I did find that my polarization is HORIZONTAL +52

Title: Re: aiming idirect to 10-02 in iraq
Post by mejustme on May 29th, 2008 at 1:47am
is it just me or did the  i site aiming window quit for you as well?  I be amazed to hear you are not getting your service from TS2  I Am my second satellite and i still havent  been able to pick up anything higher than 8 V  if any one has any answers for me as well please email me  Hope u get lucky Gecko

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