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HX50 Pointing Problem for W6 Sat

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wirelesscanuck
Ex Member


Aug 6th, 2011 at 5:26pm  
We're trying to point a dish with HX50 modem to the W6 satellite and not having much luck.  Have reviewed other posts and tried to go through suggestions posted but still haven't been able to confirm we're getting the correct satellite.

We're at Long 51.5 and Lat 35.8, pointing at 220 magnetic, elevation 37.9 and skew 34.5.

We have a maxpeak handheld which shows our signal strength between low 60's and peaking at high 70's db, however constantly says searching while set to Hughes HX W6 (have tried searching for other satellites as well and none have been found by the maxpeak).

When connecting the LNB to the modem it holds steady at 29.

We've tried many variations with both small and large adjustments.

Based on other photos seen we do not seem to have a standard mount for the dish (does not allow for the entire dish to be rotated).  The instructions indicate that the desired elevation should be reduced by 17 degrees for this set up (we've tried both, are able to peak up when the 17 degrees has been taken into account).  We seem to be finding something but we assume it's not the correct satellite?  We're also at an altitude of around 1500 metres, not sure whether this requires any adjustments?

Here's what we're working with:

<img src=https://lh3.googleusercontent.com/-6IWV03Rq7Ok/Tj1nDIn5_cI/AAAAAAAAABU/QQ9k1
SZamzA/s800/IMG_0658.JPG>

<img src=https://lh4.googleusercontent.com/-x1kUPkLDm_A/Tj1m8jV8qmI/AAAAAAAAABQ/ehPjT
r7SF28/s800/IMG_0652.JPG>

<img src=https://lh4.googleusercontent.com/-x1kUPkLDm_A/Tj1m8jV8qmI/AAAAAAAAABQ/ehPjT
r7SF28/s800/IMG_0652.JPG>

http://bit.ly/oHNX3n
http://bit.ly/pkJ9lV

Any suggestions would be very much appreciated.

arrellt@gmail.com
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« Last Edit: Aug 6th, 2011 at 9:03pm by Admin1 »  
 
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Reply #1 - Aug 6th, 2011 at 8:28pm  
...
This picture above shows an approx elevation angle for 35 to 40 deg, so that looks OK.

...
This small picture immediately above (taken from the image higher up) shows a polarisation initial setting and adjustment:

You have done one of two things.
.  (H) You have been told to use Horizontal polarisation and have set the LNB initially at the top.  You have then adjusted it +34.5 deg clockwise, as viewed from behind the dish. THIS IS ONE OF THE POSSIBLE POSITIONS ***.
or
.  You have been told to use Vertical polarisation and have set the LNB initially at the right hand side.  You have then adjusted it approx minus -55 deg anticlockwise, upwards, as viewed from behind the dish. WRONG

...
This large picture of the feed is different. In this case you have either:
.  You have been told to use Horizontal polarisation and have set the LNB initially at the top.  You have then adjusted it minus -34.5 deg anticlokwise, as viewed from behind the dish. WRONG
or
.  You have been told to use Vertical polarisation and have set the LNB initially at the left hand side.  You have then adjusted it about +55 deg clockwise, upwards, as viewed from behind the dish. WRONG

*** What name receive polarisation have you been told to use?.   Your correct position is either (H) above or 90 deg anticlockwise from that.

Signal:  29 is a really strong signal and likely to be the wanted satellite.  29 is the maximum of the scale reading when looking at noise power.  Your modem is not locking up on the wanted carrier.  Check polarisation and configuration details, particularly tuning, symbol rate, LNB type.

If your elevation is correct it is probably the wanted satellite. The next adjacent satellites are up to the left and down to the right in a 35 deg sloping line.

Site height: make no difference.

Further help:
What name receive polarisation were you told?
What is the model number of your LNB ?
What does your pdf config sheet say about frequency, symbol rate and LNB type.
What LNB types are in the screen pull down menu?  
Did you get a sbc.cfg file ?

Best regards, Eric.
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wirelesscanuck
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Reply #2 - Aug 8th, 2011 at 6:57am  
Eric,

Thanks so much for the assistance, it is incredibly appreciated.

Based on your analysis, you are correct that we set it for 34.5 degrees clockwise from behind the dish - however we have been told to use Vertical receive polarization, not horizontal receive.

What should it be set to to work with vertical receive or can we change modem settings to horizontal?

LNB details are:
P/N: 1500 287-001
S/N: 0014 7403
REV: B
NJR 2784HH

Config sheet:
Frequency - 13724
Symbol rate - 18000000
LNB type - TG_1024572-0001, Pure

There are several LNB types on the pull down, we have been selecting the LNB type indicated (...001).

We believe that the sbc.cfg file has previously been installed in the modem (staff has changed a couple times since the dish was acquired, we're trying to confirm).

Additional photos:

...
Dish with rotation set to 0 degrees ( from http://bit.ly/rgJAyz )

LNB close up
http://bit.ly/pYVEt4

LNB setup close up
http://bit.ly/otbKO9

...
Back of dish ( from http://bit.ly/nmoq3o )

Thank you again!
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« Last Edit: Aug 8th, 2011 at 8:26am by Admin1 »  
 
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Eric Johnston
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Reply #3 - Aug 8th, 2011 at 7:16am  
Polarisation:
To set (V) vertical receive polarisation, with a +34.5 deg adjustment applied:-

Step1:  Using an NJR 2784HH LNB, start with the LNB arm directly sideways, on the left hand side, as viewed from behind the dish and facing forwards the satellite in the sky. This is nominal vertical receive polarisation starting position.

Step 2: Adjust the feed system rotation +34.5 deg clockwise, as viewed from behind the dish and facing forwards the satellite in the sky. Count the amount of +34.5 deg along the scale, from the initial sideways position. If the numbers on the scale go backwards from 90, ignore the numbers.

This final position is exactly 90 deg different from position (H) above.

LNB type:
NJR 2784HH  is a fixed 10 GHz local oscillator LNB.
TG_1024572-0001 is a fixed frequency 10 GHz local oscillator LNB.
LNB P/N 1500287-0001 fixed LO=10 GHz

A typical sbc.cfg file includes this text:
[RxLnbList]
Pure=10.75,9.75
1500287-0001=10,10
Invacom=10.6,9.75
TG_1024572-0001=10,10
TG_1024572-0002=10.75,10.75
TG_1024572-0003=11.3,11.3
Invacom_bw=10,10,10.7,12.15

For a fixed 10 GHz ocal oscillator LNB you should be using pull down menu "1500287-0001" or "TG_1024572-0001"
NOT "Pure".

Config
Config sheet:
Frequency - 13724
Symbol rate - 18000000
I don't know if this information is up to date. If this information is from documentation many months old, check with Bentley Walker for up to date information.
13724 means 1.3724 GHz.  The satellite carrier frequency is 1.3724 GHz plus the LNB 10 GHz = 11.3724 GHz downlink from the satellite.
18000000 means 18 Mega symbols per second. This is a really big carrier.
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« Last Edit: Aug 8th, 2011 at 4:47pm by Admin1 »  
 
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wirelesscanuck
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Reply #4 - Aug 9th, 2011 at 6:07am  
Eric,

Thanks for the directions.

We rotated LNB 90 degrees (to the left of the arm) and then up 34.5 degrees from there.

So this is what it looks like now: http://bit.ly/nzbzlG
[img]http://www.satsig.net/pointing/vertical-polarisation-plus-35.jpg[/img]

From the front: http://bit.ly/nNeyTZ
[img]http://www.satsig.net/pointing/hx-disk-yoke-polarisation.jpg[/img]
Does that appear to be correct?

We are selecting 1500287-0001 from the menu.

The offset elevation according to our documentation is 17.3 degrees, such that we appear to be a bit low.

We will adjust so that the reverse angle in photo above is down to 69 degrees.

We will try this.  If still unable to lock on we'll try to get a new sbc file and confirm the configuration settings.

Your assistance is greatly appreciated.

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« Last Edit: Aug 9th, 2011 at 11:02am by Admin1 »  
 
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Reply #5 - Aug 9th, 2011 at 7:19am  
Your polarisation setting is now Vertical Name with +34.5 deg clockwise adjustment applied, as viewed looking forwards towards the satellite in the sky.

If your elevation is correct swing the dish sideways to find a satellite and peak up.  It is probably the wanted satellite. The next adjacent satellites are up to the left and down to the right in a 35 deg sloping line.
29 is the maximum modem signal reading until the modem locks to the wanted carrier, when RX LED will light up and the reading go up into the 90's.

Once you have found any satellite, note its angles so you can always get back to it.  Measure the elevation screw length, mark with felt tip pen or record the inclinometer reading etc.  The adjacent satellites are in a sloping line.  If you think you are too low in elevation go up and to the left a little to find the next satellite and so on..

Best regards, Eric.  


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« Last Edit: Aug 9th, 2011 at 11:09am by Admin1 »  
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wirelesscanuck
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Reply #6 - Aug 23rd, 2011 at 9:41am  
Eric,

Just a final note of thanks.

After pointing the satellite as above we uploaded a new sbc.cfg file from BW and everything sprang to life.  When we spoke to BW to start up the service we were informed that no additional tuning was required - thanks to your assistance we were bang on.  Internet is now running smoothly.

Your help has been very much appreciated!


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