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HX50 Dual Dishes Problems

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Ex Member

Jul 13th, 2011 at 7:32pm  
I am a Satellite Technician (former USMC 2834 SatCom Tech) and there are 2 other Satellite Techs with me. This is just for some background info.
We have had our two dishes setup for about a week now. We are using the MaxPeak SAM-Lite meter. Connected directly to either LNB we get a max signal on the meter of 71. We start out with a signal of 64. The meter always stays "searching". When we connect the coax cables to the modems (dual modems) we are only able to a max reading of 26 on the pointing data screen or 15 on the startup screen (forgot the screen name and I am not near it while typing this). We have set our polarization to the cutsheet of vertical. We have attempted to use  both dishes with the SAM-lite meter as well as each modem. I personally have rotated the dishes right and left (looking from the back of the dish) in order to play with the polarization.
There is an Air Force unit next to us that is using W7, the exact same dish/LNB as us, and they are currently on the internet(working). We have disconnected them and connected our SAM-Lite meter to their dish and got the same signal as we get on our dishes (around 68-69). We have also disconnected them and connected their working dish to both of our modems. Again, the readings are the same (26-29 on the Sat Pointing screen).
We are at a complete loss. I am working on getting pictures at this time. I have to use a work laptop in order to even get online for this forum. I have read many other topics on this forum and several have great ideas that we have tried but nothing yet. Our Tx and Rx codes are not what they are supposed to be so we cannot connect at all. We do not have a Spectrum Analyzer(unfortunately) either. The company we got the service from is now trying to put us on W6 Satellite but we get the same signals on the meter.
How can our meter and modems show the same on our two dishes as they do on a working dish but we cannot get connected.
Below is cut and pasted the exact cutsheet we were given. Hopefully you can read and understand it. This is for one modem only, I did not put both modems on here as this is a long post to begin with. I also replaced some of the info with an X, this is info you should not need anyways.

PLEASE HELP IF YOU CAN!!!!!! We are desperate right now as we are paying for this out of pocket, not our company.

Please enter the following information into your Hughes HX and
     on EUTELSAT W7 at 36 Degrees
     SITE ID      BHX8000      580      SSN      1903790
     V Sat Return Path      Inroute      GLOBAL
     Satellite Longitude Degrees      36      GLOBAL
     Satellite Longitude Minutes      0      GLOBAL
     Satellite Hemisphere      East      GLOBAL
     VSAT Longitude degrees      /      LOCAL
     VSAT Longitude minutes      /      LOCAL
     VSAT Longitude Hemisphere      /      LOCAL
     VSAT Latitude degrees      /      LOCAL
     VSAT Latitude minutes      /      LOCAL
     VSAT Latitude Hemisphere      /      LOCAL
     Satellite Channel Frequency      XXXXX      GLOBAL
     Receive Symbol Rate      XXXXXXXX      GLOBAL
     DVB Mode      DVB-S2-ACM      GLOBAL
     Frequency  Band /      KU / QPSK      GLOBAL
     LNB  Polarization      Vertical      GLOBAL
     Transmit Polarisation      Horizontal      GLOBAL
     LNB 22Khz Switch      OFF      GLOBAL
     DVB Program Num- User Data      20500      GLOBAL
     DVB Program Num-DNCC Data      40000      GLOBAL
     LAN 1 IP Address      LOCAL
     LAN 1 Subnet Mask      GLOBAL
     IP Gateway IP Address      LOCAL
     SDL Control Channel Multicast      GLOBAL
     IP Address
     VSAT Management  IP Address      LOCAL
     Default GateWay  IP Addr (LAN
     Return ONLY)      GLOBAL
     Set Transmit Radio to 2 Watt
     PC Settings
     Private IP No
     Public IP      LOCAL
     Avalible IP -      LOCAL
     DNS,      GLOBAL
     IP Gateway      LOCAL
     Monday, July 04, 2011      Page 1 of 1
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Eric Johnston
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Reply #1 - Jul 13th, 2011 at 9:11pm  
Satellite Channel Frequency XXXXX GLOBAL
Receive Symbol Rate XXXXXXXX GLOBAL

For W7 at 36 deg east, these should be (I think):
Satellite Channel Frequency (100kHz)  19588
Receive Symbol Rate 10000000

LNB type
There should be a pull down menu: LNB Type   xxxxxxx

If your LNB is HughesNet part number PN 1501882-0002 then it is called "Universal" and the LNB type pull down menu should be set to "Universal".  If "Universal" does not show in the pull down menu then you have the wrong sbc.cfg file loaded into your modem. The pull down menu text comes from the sbc.cfg file. Contact Bentley Walker.

Polarisation starting position and adjustment amount
If your LNB is HughesNet part number PN 1501882-0002 then the direction of receive polarisation is the same as the LNB F connector cable. You need to START with the receive polarisation vertical. Then adjust the polarisation clockwise by an amount of degrees, as viewed from behind the dish looking forwards towards the satellite in the sky.

If your dish has a giant circular polarisation scale on the back look at this image:
Note that the start position was with the feed support arm on the right hand side with the LNB F connectore pointed exactly downwards (true vertical receive).  Then using the the giant scale, count an amount of degrees clockwise.
This dish is in Afghanistan pointed at W7 at 36 east longitude.  Their calculated polarisation adjustment was +39.8 deg.

Pointing angles and polarisation adjustment amount
Use these to get your angles:
The blue line relative to your building might help.

Study the other dishes closely and make yours look like theirs.

HX Modem signal readout
The scale goes from 0 to 29 maximum, for measuring general satellite power. You will get readings on any and all satellites.  29 is a powerful satellite.
Once you are receiving the correct outlink carrier the scale will go into the range 30 - 100.
If you can't get above 29 you may be on the wrong satellite, wrong polarisation or wrong configuration settings, particularly freq, symbol rate, 22kHz tone, LNB type.
Best regards, Eric.
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« Last Edit: Jul 13th, 2011 at 10:13pm by Eric Johnston »  
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Reply #2 - Jul 13th, 2011 at 10:50pm  
Thank you and yes we have the 1501882-002 LNB. I setup our dish exactly as shown in the photo you provided with a signal on our Rx Antenna Pointing screen at 26. I am thinking that we have a configuration wrong somewhere. The dropdown list is set to universal for the LNB and 2 watts.
When looking at the US Air Force dish, they rotated the LNB and not the dish, this might be why they say their internet is crappy, LOL.
If we could connect our meter and both of our modems to their working dish and get the same readings as both of our dishes, does it sound reasonable to think that our sbc.cfg file is wrong somehow?
We are waiting on a new file from our ISP as they are trying to move us to W6. Even though when we point the az and el to W6, we get the same readings on the meter. We have not gotten it out of "searching" yet. We cannot get a good Rx and Tx code on our modems either.
I have pictures of all this if you want to view, just let me know.
Thank you for the quick response as well. Excellent site and forum you have here.
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Reply #3 - Jul 14th, 2011 at 8:21am  
sbc.cfg file
If "Universal" is showing in the LNB pull down menu, the file is OK. The file contains this text which appears in the pull down menu:

It is possible to have the feed support arm at the bottom and then to turn the feed assembly in its yokes to set the polarisation starting position and then apply the adjustment ( * ).  This is what Bentley Walker suggest as it is simple to implement.  Doing this is reported to give acceptible cross-polar measurements, but it is not my recommended method.

If the feed horn throat has "505" marked on it, this feed is called a "mode matched feed" and is intended to be always oriented so that the "505" is directly away from the feed support arm. There is a lump underneath (with 3 mode generating slots inside) which should be towards the feed support arm. The purpose is to achieve excellent cross-pol isolation and minimum interference on both downlink and uplink.

Finding the satellite

It is quite likely that you are peaked up (26) on the wrong satellite.  Try going up left and down right to check out the adjacent satellites, which are in a diagonal sloping line in the sky, at right angles to your polarisation adjusted angle.

With the 4 polarisation bolts tight, check the elevation angle thus:
When you use the inclinometer the thread should dangle from the centre of the circle in the top left corner. The small circle has a cross. Thread the thread though at the exact centre and stabilise with sticky tape on the back.

Expect to peak up at 29 and then if the satellite, polarisation and config are correect the RX LED with light up and the signal go up to about 92. Peak up.

Best regards, Eric.

( * ) This method is applicable to legacy VSAT antennas which have a truly circular symmetic feed horn and throat.
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« Last Edit: Jul 14th, 2011 at 2:17pm by Admin1 »  
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Ex Member

Reply #4 - Jul 16th, 2011 at 9:31am  
Good morning sir,

I have been following the posting and the work done to date.

It appears this system was supplied by an agent of ours. Given the issues faced and the behaviour of both the modems and the Sat meter, they have elected to migrate to W6.

You should now have received an updated configuration sheet and SBC file from Wafa. Please could you confirm this has been received and loaded along with screenshots of your modems 'Vsat Manual Commissioning' page to james@bentleywalker.com. Once we are happy that the config is 100% correct then we can focus on the alignment aspect of the installation.

When using the Maxpeak you need to select the 'W6 Uni' setting and I would also recommend downloading the latest parameters from www.maxpeak.tv if possible (requires to you register your meter).

I am confident that once the modem configuration is correct and the alignment peak you should be good to go. rest assured you will not incur any subscription charge until you are online and operational.

James - Bentley Walker Ltd.
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