SatSig topic:

Calibrating Dish for Iraq

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Jul 17^th, 2008 at 5:12am

So, as much as I have gathered, my group is still falling short of getting a signal strength of over 15% (avg is 8-12 which means squat, essentially).

We have the 1.2m Prodelin, a DirecWay6000 Modem, and 12-13 users spread across distance of 25-275'.

Our inital information suggested setting the elevation to a 35 degree inclination, a 234 Azimuth, and a +42.8 skew. We have checked and double checked all figures and insured that there was a clear LOS of the sky (was originally pointing into a tree. de de de).

Now my info suggests we are at 44 27 5.7E by 32 48 16.8N (conversion from MGRS to Lat/long).

One suggestion I have seen is to only have on the coax cable connected, while leaving the Tx cable disconnected till a strong signal has been locked (which I will try today). (will post pics later today of our setup)...

I was wondering if someone in the FOB Kalsu area has had luck getting internet through BW. I have seen conflicting azimuths for places in the area ranging from 229 to 242 and elevations varying from 34.5 to 38.5. Our dish is currently set so the connect beams that stabilize the eye to focus into the dish are at a horizontal 180 (have seen them in other setups rotated so the right side is at a possible 40-45 degree angle... Think was due in part for polarization.)

(Was also just told that it was noticed that the eye is not focusing center-mass on the dish and is skewed at an upward angle)...

Any suggestions at this point are most welcome and I will answer any questions on our setup to the best of my ability.

Thank You

Jul 17^th, 2008 at 9:07am

This page https://www.satsig.net/maps/satellite-dish-pointing-iraq.htm will help you find your dish pointing angles.

The reasons for using just the LNB cable initially are a) so you don't get confused about which cable is which and have them crossed over and b) to prevent the modem and hub automatically initiating commissioning of the service while you are still peaking up the dish and causing interruptions. Once you have perfect receive pointing you can power off, connect up the transmit cable, call the hub on the phone and power on under their verbal instruction.

If you have peaked up successfully and the readings reach 30 and won't go above 30 it could be:

The wrong satellite.
The wrong polarisation.
The wrong frequency and symbol rate set in the modem.

Readings 0 - 30 are noise power.
Readings 31 - 100 are the wanted signal quality.

A steady 15 may be a crossed over cable. I am not sure.

The conical feed horn should be aimed a point just above the centre of the dish.

Please send several images to eric@satsig.net and I will insert then here. If there 505 written of the feed throat and single and dual tick marks on a spacer tube flange please make photos of these. Take picture of the whole dish from an exact front and side views and also of the back of the dish.

What satellite are you trying to work to ? What frequency and symbol rate have you set ? What is your site ID ?
wxw
Best regards, Eric.

Jul 17^th, 2008 at 10:54am

What satellite are you trying to work to ? According to my research, 7E W3A however during the registration-user, it asks for the satellite transponder and we are at a loss...
What frequency and symbol rate have you set ? Would have to double check
What is your site ID ? See Above

Note that I wasnt as involved with the initial setup but now that it has been 4 months since getting the dish and 15 is the highest RSL, I am getting more involved and taking over for setting things up (plus my research skills appear to be much higher than that of the original "installer".

I have been told that the 234, 35 Degree inclination and 42.8 skew were given to us by a representative @ BW, but that was only telling them that we were south of Baghdad. Now that we have pinpoint accuracy of where we are located for our DW6000, we can start lining things up.

I will take pics and post them later tonight or early tomorrow (research has drained me and I have to be up in 7 hours).

Jul 17^th, 2008 at 6:17pm

Contact Bentley Walker and clarify all the required set up details for your service: sales@bentleywalker.com +44 23 9231 1118

You will be told which satellite and what nominal receive polarisation to use. They will also provide you with carrier frequency, symbol rate and IP address information so you can configure your modem

You need to tell BW your lat and long as well as the model and serial numbers of your LNB and modem.

Best regards, Eric.

Jul 18^th, 2008 at 8:49am

So, i got the customer config sheet and found I use 1386.8 and 30.00Mspb. I entered in my lat/long and that info, and it told me to point at an inclination of 34.8, an azimuth of 231.3 and a polarization of 43.8

I set all that, and the highest I got during its constant refresh was 16 RSL. I took pics of my setup so I just need to know where to send them.

Jul 18^th, 2008 at 9:06am

Email images to me at eric@satsig.net and I will put them here.

25July14:33 From discussion with Anthony and measurements here I think your side struts are too long ?.
My picture here:

Focus dimensions (white lines):
D: Top of curved surface to top of feed 123.2 cm
C: Top of curved surface to lower edge of feed 131.2 cm
B: Lower edge of curved surface to top of feed 90.36 cm
A: Lower edge of curved surface to lower edge of feed 85.6 cm

More here: Prodelin dish dimensions

Best regards, Eric.