I-Direct Installation: Guyana

Hello,

I need some help pointing an iDirect solution. The satellite i am pointing to is 30w. My co-ordinates are 3.39N, 58.41w.

Based upon my calculations we are supposed to point at Elevation=56, Az=96, Pol= - 82 deg.

We are getting some problems where we getting a green light on the Rx port at the back of the IDU, but we are not receiving any indication on the signal meter that is part of the software of the IDU.

Can someone offer some help.?

Keeron

What name polarisation were your told to receive ?

Best regards, Eric.

That depends upon whether your Prodelin antenna bracket is already stamped with elevation demarcations. If yes, then one must assume they've stamped with offset already factored in. If no, then the page that I referred to you is applicable. This diagram https://www.gdsatcom.com/Prodelin/Technical_Docs/geometry_drawings/OFFSET%20ANTE... may also help put offset in perspective.

//greg//

Hello,

We are in Guyana South America.

The manual doesn't really say, but its a Sepatriot antenna Model : TXINT-180KUG we are using.

keeron

Hello Eric,


We are using NJR 2744H as our lnb, this was requested by our provider.

Regards,

keeron

Hello,

The polarization does make some sense to me since we have mainly had it in that direction during our initial pointing attempts.

The antenna site is 5hrs driving into the jungle from where we are so we need to ensure we have all the concerns ironed out when we next go to the site.

During the initial pointing we were able to get a yellow indicator on the i-Site software but not green. I have purchase a new feed assembly for the antenna and a new i-direct IDU.  I will crimp new cables RG6 myself then go back to the site.

If there is anything else you can guide me with it is appreciated.

Keeron

My concern is the unsuitable Hispasat beam coverage pattern.

I am not hopeful.

If you have been able to find the satellite and peak up and it stays in yellow then it is quite likely that the signal is simply far too low. I'm assuming that the modem was preloaded with an options file or you tuned the modem to the wanted frequency etc using an options file yourself.

Have you tried using the same dish at a different site, further to the north west or to the south east, with any success ?  Along the north coast of Venezuela looks good.

If you can't get it to work consider a different service provider on a different satellite. NSS7 Andean beam, for example, would be more suitable.

Central Guyana is 10 dB higher (i.e. 10 times) in NSS7 beam compared with the Hispasat beam.

You don't say what is in your options file regarding bit rate or symbol rate. If the outlink carrier is just for you then it may be possible to reduce the bit rate and FEC coding (e.g. half the bit rate plus 1/2 rate FEC) to get the link just about working. If it is a shared outlink then this may not be possible or reasonable. Even if you do it working (for the downlink) I would expect signal variations due to slight satellite wobble. he uplink has yet to be addressed. I have no idea of the uplink beam pattern. It may be better or worse.

For satisfactory operation, you need about 4-5 dB rain margin under clear sky conditions.

Regarding F connectors, the centre pin must stick out about 2mm proud of the rim, so it makes good contact inside the socket. Sealing against moisture, as Greg says, is of the utmost importance. F connectors with axial compression crimping are not readily available. They must match your cable diameter and cable type exactly. The special axial crimp tool is also rather expensive.

Best regards, Eric

What is tying you to that specific satellite? Can the signal you require be made available from one with better mutual visibility?

//greg//

Hello,

Well the provider has some good rates, but i guess i have no other choice but to switch providers, Can anyone suggest some providers that covers this area?


keeron

Hello,

Unfortunately we still have been unable to point this antenna.

We have an international forest reservation (iwokrama) a few clicks away from the proposed site for the installation.

We have spoken to them and they have indicated they suffer a heavy magnetic interference in the area. They have highlighted that their compass, GPS even their directv solution experienced have intereference while setting up and operations.

How does this affect us? How can we solve this issue and get this antenna pointed?

Any suggestions ?

Keeron

hello,

I am beginning to agree with you on the coverage area. The provider said they tested the beam coverage again and that their tests prove that the coverage area is fine for the 1.8mm antenna we are using.

Anyway i have now decided to test this theory so i moved the antenna to Georgetown which according to your coverage map its 2 layers above the red dot. This should give a better signal strength.

We are attempting to point the antenna in my back yard to see what will happen. I have to take the coordinates which i will post on here to get opinions.

From the Hispasat web site https://www.hispasat.com/media//Hispasat%201D.pdf
this shows:

As you can see the America downlink coverage map is not too clear. My opinion is that Georgetown is very much at the outer edge of the beam and still about -10 dB down on the beam peak, so I am not hopeful (unless you have a small outlink carrier and the hub has turned it up very high). Note there is no uplink coverage map published so even if the downlink just works, your uplink is uncertain.

Your LNB is for the downlink frequency range 11.7 - 12.2 GHz. In your options file it will give the modem tuning, e.g. 1234000000 Hz.
Add 10750000000 (for this model LNB) gives = 11984000000 or 11.984 GHz. If this was true then you would be in red transponder 94, H Horizontal polarisation down.
For Horizontal polarisation start with your LNB side arm sticking directly upwards. Then, step 2, turn it -76 deg anticlockwise (as viewed from behind the dish and facing towards the satellite in the sky.)

The map below

shows azimuth dish pointing aligned with sides of university building.
Note: lat = 6 deg 49 min N, long=58 deg 07 min W

If there is any iDirect service provider reading this and they have a decent coverage of Guyana in the 11.7 -12.2 GHz range, please say.

Best regards, Eric.

Hello,

As you suggested the footprint is very small even over our test site. We were able to narrowly find the satellite and bring up the internet on this solution.


After speaking directly with the hub operator, they highlighted that at this site where we want to install the antenna is even further away and less likely to lock onto the network.

They suggested a 2.4m antenna with at least 4W BUC to really get a sufficient signal with no outages in rain.

We have found something on Satmex 6 that will work with the same equipment we are using.

Thanks,

Keeron

Hello,

The polarization for this down link is vertical. The elevation for this antenna is almost vertical.


Regards,

keeron Stephens

Hello,

We have the LNB sticking out to the side  and we have the antenna at the correct elevation. We have the antenna pointed in the right direction according to dishpointer.com look angle.

We have received a yellow indicator on the i-Direct modem pointing software, with signal strength of between 6 - 7. I believe we are on the satellite however since we had to assemble the feed with all three components, we are not certain that they are aligned properly.

So we have to re-check that and confirm that the feed assembly has been fitted up properly, since we are almost certain that we are pointing in the right direction.

We will work today to complete this appointment.

Regards,

Keeron

Hello,

Great advice guys, we were able to locate Satmex 6 and we were also able to connect with a very good signal strength.

Now its just to move the antenna now to the actual site in the jungle 3.48N 58.41W.

We are taking some pictures of the well pointed antenna with us on the so it shouldn't be hard to emulate.

Thanks

Keeron