SatSig topic:

Afghanistan W6 Satellite Setup

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Dec 9^th, 2007 at 8:02pm

I'll be in Jalalabad, Afghanistan soon and wanted to ask a few questions about setting up satellite service via the Eutelsat W6. For those who have setup the service, what are some items I should look for? What equipment would you recommend to aid in the aiming of the dish? I want to prepared to minimize any downtime for my company.

I'm new to the satellite arena and I barely have any knowledge regarding aiming. Could I use any analog aiming tool, such as those that operate 950Mhz - 2200Mhz? I don't want to fork-out $400 to BW for the Horizon Satellite tool and I know there has to be a cheaper alternative.

Dec 9^th, 2007 at 8:19pm

Read here: instructions on how to find a satellite.

I recommend that you practice first elsewhere, where there is no urgency.

Afghanistan is to the upper left of the map shown here:
Satellite dish pointing in Pakistan Jalalabad is marked and you can see all the streets, houses, gardens etc. I have not yet made a page that starts in Afghanistan.

Best regards, Eric.

Dec 9^th, 2007 at 10:36pm

Looks like there may be, but I don't actually know positively if there's Hughes-based internet access via W6. But if you do end up buying a Hughes-compatible rig, their proprietary OPI (outdoor pointing interface) is all the signal meter you should need. If the gateway to which you are assigned is ACP-capable, the OPI will also give a readout to optimize transmitter isolation. If you buy one before leaving the states, they're under a hundred bucks. Comes with a 22KHz blocking filter and connecting cable. Mine's an OPI-C, Hughes P/N 1031393-0003 Rev D.
See https://www.google.com/products?q=HughesNet+OPI&btnG=Search&show=dd

//greg//

Dec 11^th, 2007 at 2:04am

Thank you for the quick replies. I cannot receive the satellite equipment until I arrive in Afghanistan, but I do have access to DirecTV dish and receiver. I presume the aiming procedures are the same for a TV system as they are for a data connection. I plan to aim the dish at different satellites and eventually come back to the original satellite to confirm my capabilities. Do you think this will provide enough experience to help aim the data connection?

Dec 11^th, 2007 at 4:49am

Well, obviously satellite TV obviously is a receive-only process. So to that extent, learning how to obtain a ROTV signal will at least give you a little experience with finding the right satellite. Two way satellite internet on the other hand adds a transmitter to the equation. That's the critical part - getting the transmitter isolation optimized.

If you wish, send me a valid email address that will accept attachments. I can reply with some two-way satellite installation documents that might shed some generic light on the topic

//greg//

Dec 29^th, 2007 at 11:39pm

I have a digital satellite meter now to help me with the installation process. The only problem is that it needs some information for the satellite I'm trying to locate.

LO Frequency
Downstream Frequency
Symbol Rate
LNB Voltage (13v/18v)
Satellite Longitude

Whenever I search for the information I receive different numbers. Does anyone know the frequencies and symbol rate that I need to use for Eutelsat W6?

Dec 30^th, 2007 at 4:52am

LOF is typically hardware dependent, something you should be told by your provider. What kind of LNB/BUC are you using?
Downstream freq is assigned by the provider
Symbol rate is assigned by the provider
18v = horizontal, 13v = vertical
EW6 longitude is 21.6E (see https://www.lyngsat.com/ew6.html)

//greg//

Dec 30^th, 2007 at 6:13pm

Hi
Just to let you know that now a days its snow Falling and in the Summer there is too much wind so you should find the Dish and other thing accordingly .

Thanks
Jani

Jan 30^th, 2008 at 5:16pm

Well, I finally got the satellite connection up and going, but the speeds can be rediculously slow, even during non-peak times of the day. We have the Star Pro system (1.2m dish) through Bentley Walker with a downstream rate of 2048 Kbps and upstream running at 512 Kbps. Using the satellite aiming device the best signal I could receive was 72% (not sure wha dB this translates to) and the BER fluctuates between 0.00010 and 0.00005. The location the dish is sitting provides a clear view of the sky, but a small portion of the lower part of the dish may be blocked by a fabric tent. We're moving locations in a few weeks where there will be no lower restrictions. I also found out that we're not using W6 (like the salesperson told me), but AM22 (Sesat 2).

There are no more then 10 people on the connection at a time and I've even brought the connection down to just one computer during the slow times and the speed remains the same. Will improving the BER mean an increase in the download rate? Any suggestions on improving the speeds?

Jan 30^th, 2008 at 6:35pm

If your receive QPSK-BER is at or lower than 0.00010 then you have a good download receive signal and will have no errors at all in your received data after FEC. You will see that the number of uncorrected errors after FEC, hardly increases at all (I hope!).

You need to get the hub to measure your transmit signal as it received at the hub and resolve any issues. The hub can adjust your transmit power up and down. If the level is still too low you may be asked to check your dish. The satellite needs to be at the centre of the beam (i.e. half way between equally degraded levels on either side). The dish rim needs to be flat. Use fishing line or thread up down and across the middle and check for just touching.

The hub need to know your lat and long so that your transmit bursts arrive at the satellite at the correct time. If you, or any other site, have the wrong burst timing then your transmit bursts may mutually overlap and both will fail.

The hub can also observe and investigate any interference problem.

There may well be traffic or routing problems. Traffic or routing problems need to be investigated and resolved by IT people at the hub. Bentley Walker need your help. Tell them you have traffic problems and describe the symptoms.

Best regards, Eric.

Jan 30^th, 2008 at 7:05pm

I can understand that there may be a disparity between military and civilian/commercial BER standards Eric. But a BER of 1x10e4 would be have failed QC standards back in my Navy days. Nothing less than 1x10e6 was acceptable.

Maybe I'm over-reaching, but I wanted to respond that this particular issue - to include what I consider substandard BERs - may be related to an antenna pointing error. For 10 users on a dedicated 2048/512 connection that is.

Alternatively, the gateway server may be overloaded - and an unacceptable CIR is at fault. Or - and I admit I didn't run a link analysis - perhaps a 1.2m dish and a ?w BUC is insufficient.

//greg//

Jan 30^th, 2008 at 11:27pm

In respect of LinkStar modems the QPSK BER which people measure during pointing varies from about 0.01 which is poor to 0.00001 which is excellent. The QPSK BER refers to the situation prior to the application of FEC. Values in the range 0.0001 to 0.00001 are normal and good.

The corresponding BER rates after FEC are like <1E-9 or zero counts in any reasonable amount of measuring time, even at 54 Mbit/s. Sometime you get zero errors in a whole day. See the cumulative uncorrected error count.

With a receive QPSK BER of 0.0001 to 0.00001 there will be virtually no errors at all in the data and no effect on the service.

What is worth noting is that a good enough receive perfomance does not necessarily mean that the antenna is centred on the satellite as various random readings will be displayed wherever you point the antenna across the fairly flat central 0.5 dB beamwidth.

This problem of installers being unable to find the beam centre is particularly evident when the satellite downlink carrier is very strong and the customer dishes rather large. I do wish sometimes that a very weak carrier was available for pointing so as to make is difficult to find the satellite, that way the installers would be forced to point accurately. It is so easy to say I've got a really good signal and then just give up the effort. Transmit beams are narrower than receive beams.

It is thus important, when pointing an antenna to move off in each direction till a significantly degraded and identical degraded level is determined either side of the beam, like 0.01, and then count equal numbers of flats in on both nuts, or whatever, till you centre the beam by mechanical movement.

I doubt that the service is 10 users on a dedicated 2048/512 connection as that would be costing them around $17,500 per month. It is more likely that they are on a shared tariff at a very much lower monthly price. Dedicated service of 2048/512 would suit a site with 200 PC users.

Regarding BUC power I wondered about this also. This should be resolved when the hub measures the carrier from the site to the hub and determines if it is sufficient for 512k operation. If not, I would suggest checking the dish pointing and the dish rim for possible distortion. More BUC watts may help but let's see first what the hub measures.

If all the 'radio' aspects prove to be clear then the problem is in the traffic / routing / congestion area, but this won't get cleared by magic, the site needs to report the symptoms to the hub so they can investigate.

Best regards, Eric.