Gilat System Alignment Options

bixelps

New Member
Original poster
Dec 18, 2008
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Virginia
We are an Christian charity constructing a hospital in south Sudan. We have determined to install a 2-Way satellite link for VoIP and Internet access at our site. I have selected GlobalTT as our ISP. They offer Gilat hardware and space on the IS10 KuBand satellite.

So now I am getting down to the nuts and bolts of getting this system installed and operating. We have sent one of our folks to VSAT installation training and now I need to equip him with the stuff he will need.

Being a charity the budget is very tight. For proper alignment a spectrum analyzer is recommended. The modem we will get is the Gilat SkyEdge IP and I have attached the technical datasheet on this modem.

Does anyone have experience with this modem? Does it have a web interface and a way to determine the signal strength onboard? Can this be used instead of a spectrum analyzer?
 

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  • Brochure SkyEdge IP 11_2006.pdf
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Does anyone have experience with this modem? Does it have a web interface and a way to determine the signal strength onboard? Can this be used instead of a spectrum analyzer?
The last two questions are answered right in the brochure you uploaded. If a usable response to your first question is not forthcoming here, you should consider asking on this UK-based satellite internet help site: Satellite Internet Forum: Index page

//greg//
 
Not sure how you determined that the brochure contained the answers to my questions. What exactly do you think says that no spectrum analyzer is needed?
 
Not sure how you determined that the brochure contained the answers to my questions. What exactly do you think says that no spectrum analyzer is needed?
You: Does it have a web interface ...
Brochure: SkyEdge IP has a Web interface...
You: ...and a way to determine the signal strength onboard?
Brochure: ... Auto pointing tool

What that means is that you use a conventional web browser as the modems user interface. The auto-pointing tool is typically imbedded in the Web interface. This is the information that strongly suggests to me that - while always useful - a spectrum analyzer in this case would likely be redundant.

That said, I have never even touched a Gilat SkyEdge myself. But the brochure suggests strong similarities to others that I have. So to avoid any shadow of doubt, I hoped other members would be able to respond with actual hands-on experience. If not, I'm sure someone at SatSig can.

//greg//
 
greg,

I appreciate your response. I wish I knew more about this "Auto pointing tool" but it is conforting to know from your experience that in similar modems this type of feature makes the spectrum analyzer redundant.

I posted in the Gilat VSAT forum of the board you suggested. This forum seems to have very little traffic on it. In the two days since I posted there have been no posts of any kind on that forum. Maybe I should post in another forum....

Paul
 
Setting up a Gilat skyedge IP modem without a satellite meter.
Read these instructions carefully and completely before attempting the procedure. Your modem must already be properly configured to your correct account parameters before using this method.

1. You MUST start with a perfectly plumb mast or aiming the dish will be an exercise in frustration.
2. make a note of these numbers by using a generic dish pointing tool or obtain them from your ISP:
a. Magnetic Azimuth
b. Elevation
c. Skew/polarization
3. Set the Elevation in your dish
4. Set the Skew/feed polarization on your dish as exactly as you can.
5. Set your compass for the Magnetic Azimuth
6. Put the dish on your perfectly plumb mast.
7. Add the feed arm to the dish. Make sure that this operation does not change the plumb of your mast.
8. Connect your coax cables between the dish and modem. “RF Out” on the modem is transmit and connects to the transmitter. “RF In” on the modem is receive and connects to the LNB which is the little square box out on the end of the feed arm. Make sure your connections are tight.
9. Connect the modem to your computer with a Crossover Ethernet cable, like the one supplied with the modem.
10. Power up the modem and let it boot for at least 5 minutes. The modem is booted when you can access the SkyManage page as described in step 12, below.

11. Boot your computer and set it's network connection TCP/IP properties to 192.168.1.2. OK your way out of the network properties pages and open a browser.
12. Address the modem’s SkyManage page with the browser, using the address 192.168.1.1
13. When you have the modem’s “Skymanage” page displayed in your browser, select “Telemetry” from the left menu.
14. You will need to monitor the “REC” light on the modem to initially find the satellite.
15. Start rotating the dish on the mast. Using your compass, you should know approximately which direction you’ll be pointing. Make wide, slow, sweeps as you turn the dish on the mast while monitoring the “REC” light on the modem. Sweep 20 to 40 degrees on either side of your target direction!
16. When the modem’s “REC” light illuminates, you have found the satellite.
17. Tighten the 4 nuts on the mast clamp to keep the dish from turning on the mast.
a. NOTE: If you lose your REC light during this process, try lowering the elevation a couple degrees. If you don’t get your REC light back, then return your elevation to the original position, loosen your mast clamp and search side to side very carefully.
18. Once you have your REC light, you will have to wait while the modem establishes communications. This can take about 5 minutes. In particular if this is the first time the modem is booted with this configuration and it's the first time it get RX lock on the sat then it will start a software download that can take up to 20 min.
a. The sequence after the receive light comes on and the software download if applicable is complete is:
b. After some time, the Sync light will come on.
c. After some more time, the On-Line light will come on and the Sync light will go out.
d. Eventually, the Sync light will come back on.
i. NOTE: It is not unusual for a modem that has been moved to go through the above sequence 3-4 times before it stays up with 4 lights on. Each time it goes through the sequence, it is adjusting its timing for the best communication with the satellite.
ii. NOTE: If this is the initial commissioning of the modem, a third bar graph will appear to show the progress of a critical software download. As long as your EbNO is 5 or greater, leave the dish alone until the download is complete. After the download is complete, the modem will reboot 3 or 4 times. Eventually, it will settle down to having PWR, Rx, SYNC, and ON-LINE lights on and steady.
e. Shortly after you have all 4 lights on and steady, you should get a display on the Telemetry page on the lower bar, labeled: Rx signal EbNO
f. This is your Receive Signal Quality and you now must fine tune to get this at high as possible (see how close to 8 or more you can get).

19. You will now fine-tune azimuth and elevation for the strongest Signal Quality by monitoring the Telemetry screen on your computer.
a. Fine tune the azimuth.
b. Fine tune the elevation.
c. Repeat this procedure until you are confident that you have the highest Signal Quality possible as measured by the “Rx signal EbNO” number on the Telemetry screen. Use the number to the left of the bar, not the bar, as the bar is difficult to read.
d. Tighten the elevation locking knobs.
e. Now you can verify that you are on-line by attempting to browse.
f. Call the NOC and make sure that you are aimed cleanly and passing criteria.
g.
h. Once you are passing criteria, you’re good to go. If the modem doesn’t come back to 4 lights after a CW from the NOC, power cycle the modem and give it 5 minutes or so.



What if you can’t find the satellite?
1. Make certain that your antenna’s feed is set to the correct polarity.
2. If you don’t find the satellite by sweeping slowly with the initial settings in the dish, change the elevation by ½ degree, and try another slow sweep.
3. Continue this methodical search, changing elevation a half degree at a time and sweeping slowly.
4. If you cannot find the satellite after sweeping, and changing a half degree per sweep, until you have tried about 4 degrees up and 4 degrees down from the numbers you got from a Point Dish program, then something very basic is wrong and you must back off and start over from the beginning.
a. Make absolutely, positively, certain, that your mast is perfectly plumb.
b. Make sure your cables are connected correctly
c. Start over from the beginning of these instructions.
d. Always work slowly and methodically.
e. If you get frustrated, take a break. Do something else for a while and return to it at a later time. Then start over from the beginning, rechecking all your previous work.
 

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