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Pages: 1

Evolution x3_ South America

(Read 2016 times)
Ex Member
Ex Member

Nov 26th, 2011 at 11:34pm  

We are trying to locate AB1 using evolution x3 IDU. Below is the following info for the site

Address:Test site
Latitude: 6.8204°
Longitude: -58.1315°

Satellite: 12.5W ATLANTIC BIRD 1
Elevation: 37.0°
Azimuth (true): 96.6°
Azimuth (magn.): 112.6°

We are using a 1.2m Prodelin Antenna, with 2784H LNB and a 3watt BUC.

Our provider is one with no after hours support, which makes it more difficult. We have been able to get up to 4 using isite however we not certain if this is the correct version of isite we are using.

How can we confirm what version of isite to use?
If we move the antenna - up, down, left right the signal drops. Any suggestions?
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Eric Johnston
Senior Member

Posts: 2109
Reply #1 - Nov 27th, 2011 at 7:27pm  
The good news is that you have found a satellite. Carefully measure and mark the angles so you can always get reliably back to this first found satellite. The other satellites are in a steeply sloping line up the sky.  It is helpful to know this if you are not on AB1, but need to look at the next ones either way.

One important setting is the polarisation angle. This is the rotation of the LNB/BUC/Feed horn assembly in its yoke system in front of the antenna.

Read the information from your provider. It should say what is the name of your downlink polarisation - either Horizontal name or Vertical name.

Setting polarisation is two step process.

Step 1. Set the nominal named polarisation.

If name=vertical then turn the LNB/BUC/feed system so that the broad faces of the 2784H LNB rectangular input waveguide are on top and underneath.
like so: ...
Note that the half dipole pin inside the waveguide is Vertical. It does not matter up or down.

If name=horizontal then turn the LNB/BUC/feed system so that the broad faces of the 2784H LNB rectangular input waveguide are on either side.
like so: ...
Note that the half dipole pin inside the waveguide is Horizontal. It does not matter which side.

Step 2. Apply the polarisation adjustment angle.
See https://www.satsig.net/maps/satellite-tv-dish-pointing-caribbean.htm for your pointing and polarisation angles. Your polarisation adjustment amount is -80.5 deg.  Minus means anticlockwise as viewed standing behind the dish and facing forwards toward the satellite in the sky.
In your case, you need to turn the feed system by an amount of 80.5 deg anti-clockwise, as viewed facing forwards towards the satellite in the sky.

If the application of the adjustment amount causes the LNB to hit the metal yoke base then start 180 deg the other way.

Best regards, Eric.
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Ex Member
Ex Member

Reply #2 - Nov 28th, 2011 at 1:48am  

We were unable to find a decent signal quality, we got up to 5.8 on the iSite software antenna pointing software.

We change to a 1.8m antenna and within 4 mins we were locked all the way up to 18 on the same iSite antenna pointing software. Our provider assured us that we would be able to get a locked signal with a 1.2m antenna.

I guess we have to take this up with them, since its one of the service providers that advertise in the forum.

We will continue to try with the 1.2m to see if it can work.

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