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HX50 installation  Eutelsat W7 Afghanistan

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Aug 11th, 2010 at 5:55pm  
All,

I am in desperate need of some help with one of my Bentley Walker systems. We have three in total and all three are necessary to provide the proper amount of bandwidth to our internet access customers here.

To address some connectivity problems BW recommended changing one of our dishes from SESAT2 to Eutelsat W7 which would require purchase of a new head (Assy, Radio, Anubis - Intl, 2W, 1M P/N: 1502122-0121) and of course repointing. Using the tools on this site this is the math that I came up with and BW confirmed this to be more or less correct:

Latitude = 32.4, Longitude = 62.2
Lat    = 32 degrees,   22.0 minutes   North
Long = 62 degrees,   9.5 minutes   East

Beam elevation= 42.9, Azimuth= 219.3 (or 219.8 )(magnetic compass), Polarisation= 34.8

Everything was installed using a lot of the guidance that I have found on this forum, such as placing the head on the feed arm with the 505 and notch up and without any rotation (this is odd to me as our SESAT2 dishes are at 0 degrees on the rear plate and the head is rotated..). Regardless, I went with it: The LNB is at a 90 degree angle.

After 4 days of standing on the roof in 100+ degree weather the result I came up with is that after resetting the modem to factory, uploading the SBC.cfg, and using the settings provided by BW that the modem will only show "15" or "29" depending on what I try with rotating the head.

I know that I am on the bird, my SatBuddy is showing "64" and beeping rapidly (my SESAT2's show "53" and "54" on SatBuddy while providing 91 - 92 on the HX50 itself). I checked my azimuth, elevation, and polarization (set by rotating the dish clockwise at the rear) at least four times and cannot find any problems.

Here are the settings from my modem (also put a screenshot in the ZIP file, see below):

Current Software Image Executing:        Fallback.bin
Creation Date [Release #]:               Oct 17 2008, 14:23:44 [5.8.0.35]
NAT Status:                              Disabled
DHCP Server Status:                      Enabled on Lan1
Firewall Status:                         Disabled
VSAT Zipcode:                            Not Available
=======================================================================
Parameter                                Value entered     Value in use
--------------------------------------   --------------    ------------
VSAT Return Path:                        Inroute           Inroute        
Satellite Longitude in degrees:          36                36            
Satellite Hemisphere:                    East              East          
VSAT Longitude in degrees:               62                62            
VSAT Longitude in minutes:               9                 9              
VSAT Longitude Hemisphere:               East              East          
VSAT Latitude in degrees:                32                32            
VSAT Latitude in minutes:                22                22            
VSAT Latitude Hemisphere:                North             North          
Satellite Channel Frequency:             18826 (x 100Khz)  18826 (x 100Khz)
Receive Symbol Rate:                     5000000  Sps      5000000  Sps
Receive Polarization:                    Vertical          Vertical      
Transmit Polarization:                   Horizontal        Horizontal    
LNB 22KHz Switch:                        On                On            
DVB Mode:                                DVB-S2-ACM        DVB-S2-ACM    
Frequency Band / Modulation:             Ku / QPSK         Ku / QPSK      
DVB Program Num for User Data:           20500             20500          
DVB Program Num for DNCC Data:           40000             40000          


I am uploading the photos to http://www.farahinternet.com/satphotos_08112010.zip (if this does not work please try later because it will take all night to upload from here which is now in progress). These photos show the entire setup and my measurement of the elevation using the inclinometer from this site.

I desperately need help on this one, I cannot spend every hour of every day on the roof playing with this thing!
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« Last Edit: Aug 13th, 2010 at 8:54pm by Admin1 »  
 
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Eric Johnston
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Reply #1 - Aug 11th, 2010 at 8:39pm  
Many thanks for the images, now all received OK.

You have the correct az, el and polarisation calculations.
Inclinometer
Since the satellites are in a distinct sloping line across the sky it is highly likely that you are pointed at the correct satellite - or possibly to one on either side (to upper left or lower right).
It will probably help to add a few deg to the polarisation adjustment.  Make it +38 deg clockwise.

1.   Regarding equipment assembly, the feed horn throat 505 must always be directly away from the feed support arm. You definitely have this correct.

2.  Polarisation

...
You have the new HX universal type LNB PN 1501882-0002.
As shown, with whole dish rotated so that the feed support arm is at the bottom, and the LNB connector pointed sideways then you have a Horizontal receive polarisation starting position.

You want Vertical receive polarisation starting position, so get behind the dish, and while facing towards the satellite in the sky, turn the whole dish 90 deg anticlockwise.  The feed support arm is now on the right side.  The scale on the back probably reads - 90 deg. You are now at a Vertical receive polarisation starting position.

Now apply the adjustment amount. Get behind the dish, facing towards the satellite in the sky, and turn the entire dish by an amount of +38 deg clockwise.  Count the amount of degrees as you go along along the scale.  The scale will probably read -52 deg.

Facing towards the satellite in the sky, the feed support arm will now be to the lower right.

3. If you get a maximum of 30 that means you have pointed at a powerful signal. You will get readings up to 30 on any and all satellites.  Once your modem locks to the correct signal the reading will go right up to around 90

. It could be the wrong satellite.
. Your polarisation may be completely wrong (e.g. 90 deg error) and you are getting a strong signal from the wrong polarisation.
. Your polarisation may be about half wrong (e.g. about 45 deg error) and you are getting half of the wanted signal and half of the wrong polarisation signal.  This causes 100% interference and a strong total signal power, but it won't work at all.
. Your configuration is wrong.  Particularly the L band frequency setting and symbol rate. I believe that you have correct tuning 18826 and 5000000 symbol rate for W7 satellite, so this does not apply to you.
. If you have a simple single local oscillator frequency type LNB, you may have the wrong model number. There are several types of simple LNB with different local oscillator frequencies. This does not apply to you.
. Some LNBs have switchable LO frequencies. Your PN 1501882-0002 is a universal dual frequency switchable type.  In this case it matters if the 22kHz tone is on or off.  It also matters what type LNB you select in the pull down menu.  It also matters what SBC.cfg file you use. The SBC.cfg makes the pull down menu, like this:

[RxLnbList]
Default=9.75,9.75
Pure=10.75,9.75
Invacom=10.6,9.75
TG_1024572-0001=10,10
TG_1024572-0002=10.75,10.75
TG_1024572-0003=11.3,11.3

You have "Pure" selected.  The numbers after the = are the alternative local oscillator frequencies.  I understand the Invacom (Invacom=10.6,9.75) with the tone on selecting the first (higher) LO frequency 10.6 GHz.  The other examples relate to simple fixed frequency LNBs, where the tone has no effect and should be left OFF.

Note: Satellite frequency - LNB local oscillator frequency = L band modem tuning frequency.

Best regards, Eric.
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« Last Edit: Aug 13th, 2010 at 8:53pm by Admin1 »  
 
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Reply #2 - Aug 12th, 2010 at 2:44am  
Eric,

All of my current settings are exactly what BW provided and my head/LNB are the exact model that BW told me I needed to buy from them to connect to W7.

My personal opinion right now is that I installed it wrong and of course you will need the images to be able to tell me if that is the case. I feel very confident that I am pointing to W7 with a strong signal.
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Reply #3 - Aug 12th, 2010 at 2:55am  
1502122-0121 is a Hughes part number, this is what BW sold to me to replace the one I was using on SESAT2. My ZIP, once ready, has a picture of the sticker.
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Reply #4 - Aug 12th, 2010 at 4:00pm  
I tried -52 deg on the rear of the dish and the feed arm ended up pointing in a completely different direction. From there I tried to adjust my azimuth but was unsuccessful locking a signal.

Frustrated and to Eric's dismay I tried the BW prescribed method of setting the dish to 0 deg and adjusting the LNB to +40 (this is what worked best while peaking). I immediately grabbed a 71 on the HX50 and the firmware started downloading.

Right now I have a 83 and BW has not yet activated the new modem. Is this going to work OK? I tried peaking with very, very precise changes to the azimuth and elevation nuts and this was the best I could come up with.
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Reply #5 - Aug 12th, 2010 at 4:10pm  
I am pleased you have found the correct satellite and polarisation - note the direction that the LNB is pointing.

The BW method is fine for a feed system that does not have the 505 on top, and fat lump underneath, the feed horn throat.

The feed with the 505 is not symmetrical and must always be set so the 505 is away from the feed arm.  The feed is designed to cause some cross-polarisation which is designed to cancel the inherent cross-pol caused by having an offset feed design.  The result is excellent cross-pol isolation.   If you have the 505 turned, then you will get a poor cross-pol performance and both receive and cause interference from and to the people using the other polarisation.

When you rotate the entire dish using the large circular polarisation scale the beam 'should' stay pointed in the same direcvtion.  Obviously it sags down a bit while you have the 4 screws loose.

Best regrads, Eric.
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Reply #6 - Aug 12th, 2010 at 4:17pm  
I wish I would have taken more pictures. At -58 on the dish the feed arm was pointing far right (standing behind the dish looking at the sky) of the correct azimuth.

For your notes though the adjustment for W7 seems to be even greater than you suggested.

I have a problem with my other two systems on the same roof where one will drop out (no transmit activity even though signal is 92+) and the system has to be force ranged to bring it back online. This happens at least a few times per day.

Is this the type of problem you were suggesting is typical of the BW polarization method?
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Reply #7 - Aug 12th, 2010 at 7:31pm  
Quote:
At -58 on the dish the feed arm was pointing far right (standing behind the dish looking at the sky) of the correct azimuth.

The beam direction (both azimuth and elevation) should have stayed constant, aiming at the satellite (subject to minor sagging down while the 4 bolts are loose).  You can get an approx idea of the beam direction by putting a long thin straight stick under the edge of the dish beside the feed arm and resting the stick on the top rim of the circular feed horn aperture (Transmit powered off !!). The stick points directly at the satellite (approx).

Quote:
one will drop out (no transmit activity even though signal is 92+) and the system has to be force ranged to bring it back online
Is this the type of problem you were suggesting is typical of the BW polarization method?

If the other system does not have the 505 type feed, it is quite OK to rotate the feed assembly in its yokes to set the polarisation start positon and then to apply the adjustment angle.

It is most unlikely that a polarisation problem could cause several transmit outages per day. More likely a loose connection on the BUC cable or software problem at your site or the hub.  Could the BUC be overheating ? Tell BW about this if you suspect software as the cause.  Polarisation problems will cause you to suffer interference into your receive system.  This interference could be steady or intermittent due to whatever the people renting the opposite polarisation are doing. Of concern to the hub is the effect of any polarisation error causing you to interfere with someone on the opposite polarisation.

Best regards, Eric.
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Reply #8 - Aug 13th, 2010 at 2:18am  
They know about the issue but no one has any real idea why it's happening.
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Reply #9 - Aug 13th, 2010 at 3:29pm  
I got this system up, current signal is 87 and it seems to be performing much better than my SESAT2 systems.

The ranging problem I had with SESAT2 culminated in a pretty severe outage over at BW and once it was fixed it seems the ranging problems went away, at least thus far.
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Reply #10 - Aug 13th, 2010 at 5:04pm  
Hi Geoff

Glad to hear your system is up and running, understand James here has been helping you and we are ready to help you with any matter connected with your Satellite system.

Best Regards,

A Walker
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Reply #11 - Aug 14th, 2010 at 5:13pm  
Deathnova, where in AFG are you?  I'm in KAF, just got a BW HX50, trying to point at W7 for 3 days now.  Seems we have the same trouble, I think probably polarisation.

Any advice you can offer will be well worth a pint when we get home.
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Reply #12 - Sep 29th, 2010 at 5:30pm  
im in Herat area in Afghanistan. just got my dish up on a steady pole and have tried a few hours moving it around to find a strong signal, my dish signal remains at a constant 29 on the scale no matter where i aim it. extreme changes in elevation or azimuth never see a change from 29. the scale just stays at 29 always. what am i doing wrong here? now secondly my LNB is straight up and down with the cable coming out of the top while the feed arm is at the bottom of the dish (when bolting the horn to the LNB i turned the LNB to this position from the horizontal position it was) my horn is the 505 type with the lump that is facing the feed arm and the 505 is away from the arm, this should equal "vertical" RX signal for the W7 sat that BW told me im on. CORRECT? so i am at Latitude = 34.12, Longitude = 62.23 and your pointer software (i used the link i found on this site) says... Beam elevation= 41.4, Azimuth= 217.3 (magnetic compass), Polarisation= 33.1 , so to get the pol of 33.1 i should move the entire dish approx 33.1 degrees clockwise so my feed arm (if i am standing behind the dish looking at the sattelite) should be in the lower left area. is this correct?  any other help would be appreciated.

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Reply #13 - Sep 29th, 2010 at 6:37pm  
Quote:
im in Herat area in Afghanistan. just got my dish up on a steady pole and have tried a few hours moving it around to find a strong signal, my dish signal remains at a constant 29 on the scale no matter where i aim it. extreme changes in elevation or azimuth never see a change from 29. the scale just stays at 29 always. what am i doing wrong here?

1. First we need to sort out your fixed 29.  Something is seriously wrong, as the level should normally be far lower than this when the dish is not pointed at a satellite.  When the dish is pointed at any satellite the noise power reading will go up, to a maximum of 29 for a very powerful satellite.

Warning: You must power off at the mains wall swithch before doing anything with the coax cables. Leave the low voltage multi-way connector from the power supply module to the modem always connected.

The receive coax cable connects from the small LNB side module to the SAT IN socket on the modem. Make sure this cable is connected and trace it out to ensure the cables are not crossed over.  Initially leave the transmit cable disconnected at both ends. Check that the centre pins of the F connectors are 1.5mm proud of the rim, and that there are no braid fragments shorting the inner to the outer. When screwed in, the centre pin should go smoothly into the hole and not push back the cable within the plug outer tube. Use just finger tightness, not a spanner.

When powered on and not pointed at a satellite the reading should be very low. It might increase slightly if you put your warm hand over the feed.  If you aim around the sky you will get readings on all satellites and also a possible slight increase if you point the antenna beam towards warm hills/buildings/trees/ground/sun. If you get such results your LNB is almost certainly working well.  If it remains fixed at 29, power everthing OFF, disconnect both coax cables and power the modem on again, alone.  The reading should be near zero. If fixed at 29, the modem or its software is faulty. If the modem tests OK then try again with the LNB.  If the 29 comes back the LNB may be extremely noisy or oscillating - most improbable but not impossible. Is your antenna right next to some high power transmit facility ? Put something totally blocking (e.g. aluminium foil) across the feed window. If the reading goes down from 29 to a low reading maybe there is extreme high level local interference noise.

Quote:
now secondly my LNB is straight up and down with the cable coming out of the top while the feed arm is at the bottom of the dish (when bolting the horn to the LNB i turned the LNB to this position from the horizontal position it was) my horn is the 505 type with the lump that is facing the feed arm and the 505 is away from the arm, this should equal "vertical" RX signal for the W7 sat that BW told me im on. CORRECT? so i am at Latitude = 34.12, Longitude = 62.23 and your pointer software (i used the link i found on this site) says... Beam elevation= 41.4, Azimuth= 217.3 (magnetic compass), Polarisation= 33.1 , so to get the pol of 33.1 i should move the entire dish approx 33.1 degrees clockwise so my feed arm (if i am standing behind the dish looking at the sattelite) should be in the lower left area. is this correct?

2. If you have the white HX universal type LNB PN 1501882-0002, then with the F connector pointed upwards you have a Vertical receive polarisation starting position, which is what you want.  Note that the transmit module will be on its side, with the fins facing sideways.
Now simply turn the whole dish 36 deg clockwise, as viewed from behind the dish. Use the giant circular polarisation scale. The feed support arm will be to the lower left,  as viewed from behind the dish, and the beam pointing will be unchanged. Re-tighten the 4 bolts on the polarisation plate.

Please confirm the model number on the LNB.

This may help getting your beam elevation correct.
Elevation: Set the angle using the sloping plate behind the dish like so:
inclinometer
If you don't have an inclinometer you can make one like that above by printing out this page  How to make inclinometer
If you use your own inclinometer make sure it reads towards zero as the dish is pointed down and increases towards 90 when the dish is pointed upwards. It is quite likely that your own inclinometer will read backwards, for example. In which case try putting it the other way round and looking at it from the other side or turn it through 90 deg.

Then swing the dish boldly sideways and find a satellite.  The satellites are in a sloping line from up at south to down at south west, like where the sun moves across the sky in spring and autumn.  You may need to go up left or down right if you get the wrong one initially. If you get a big peak that goes up to 29 and your elevation is as set above then are probably on the correct satellite but the modem config is not yet correct. 

Best regards, Eric.
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« Last Edit: Sep 30th, 2010 at 9:15am by Admin1 »  
 
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Reply #14 - Sep 30th, 2010 at 5:27am  
Yes on both my systems i have the "universal" type LNB. gonna try again this morning and ill let you know what i find.
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