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HX50 SETUP HELP NEEDED

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wigglyamps
Ex Member


Aug 14th, 2010 at 4:56pm  
I'm in Kandahar and we've recently purchased a BW HX50 VSAT.  We've spent the last 3 days now trying to get the thing to work but with no joy.

The 3 angles I have (to hit W7) are Az 225, El 41 and Pol 39. Despite 3 days of adjusting, trying different polarisation methods (rotate dish/rotatel LNB) we can't get anything over 29 on the modem.

BW have sent me 3 CFG files so far, the first of which seemed to be corrupt, the second two loaded fine, but have not helped.

I'm confident that the Az and El are correct, but concerned that the (Universal) LNB may not be setup correctly, ie initial vertical or horizontal polarisation.  We've tried all variations but to no avail.

Can anyone help?
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A.Walker
Ex Member


Reply #1 - Aug 14th, 2010 at 5:16pm  
Dear David

I have one idea that is you could be not aware that you need to take 18.5 degrees off you angle to the Satellite thats because we use an offsett dish. what meter are you using ?

Gary Delaney is going to send you some parameters for a HX high band service we have on W7 as well as the low band one that you are presently configured now, we also have two installesr in Khandhar who might be able to help you nayway dont worry we will get you up and running one way or another

Best Regards

A Walker
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wigglyamps
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Reply #2 - Aug 14th, 2010 at 5:38pm  
Mr Walker,

Thanks for your swift reply, at last some hope!

Which angle has the offset?  Is it + or -? For the azimuth I'm using a prismatic compass, for the elevation the printed inclinometer.

I know of Jeremy and Brad, I collected the systems from them.  I work just outside of KAF in FOB Lindsay, and because they're US Mil, they can't go outside the perimter.  I was told by BW Tech Support today that there is a LN who can help, but I've not heard from him yet.

How close to the sat do we need to be to get a reading over 30?  We must have covered every conceivable angle in the last 3 days and it's never been over 29.  Today with a new CFG, it wont go over 15, and even a big swing way off track, it still stays at 15.

Please help, before I tie the dish to my feet and take a leap into Poo Pond!

Dave
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Eric Johnston
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Reply #3 - Aug 14th, 2010 at 8:06pm  
The signal reading scale works in two ranges.

0 to 30 is noise power. You will get readings on any and all satellites.  30 is the highest possible noise reading.  If your elevation (Up/down) is correct you are probably peaked up on the correct satellite. The next satellites are slightly up left (towards south) and down right (south west)

If your modem does not lock to the wanted carrier and  gets stuck at 30 the reason is something to do with polarisation, LNB tone, frequency tuning or carrier symbol rate.

Once polarisation, LNB tone, tuning or symbol rate are correct the reading will go up to around 90. Once above 30 the reading refers to the wanted signal quality.

Configuration details HX W7 AFG

Going by a recent HX W7 Afghanistan installation we had:

Hub operator: Bentley Walker
Hub location: Turin Skylogic teleport
LNB:  HX universal type LNB PN 1501882-0002
Feed: 505 mode matched
Antenna: 1.2m with large circular polarisation scale at the back of the wedge shaped box.
Polarisation: Vertical (this means the NAME of the receive polarisation before the adjustment amount is applied)
LNB type : Pure
LNB tone: ON
Tuning: 18826
Symbol rate: 5000000
SBC.cfg
[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

If your details are different please say. There is a new BW W7 service coming up from Cagliari teleport. Vertical, LNB tone off, freq=19582, sym=9000000, LNB type="Universal" - details not verified yet.

To set receive to Vertical polarisation with +42 adjustment. Always view from behind the dish, facing towards the satellite in the sky.

1. Assemble with the feed arm at the bottom and the LNB connector pointed to the left.See picture. Now is true horizontal receive polarisation. The 505 must be directly away from the feed support arm.
...

2. Turn the entire dish 90 deg anticlockwise (scale -90), Feed arm at right hand side. Now is true vertical receive polarisation.

3. Apply the adjustment. Turn dish 42 deg clockwise counting along the scale. Scale probably reads -48

When you rotate the polarisation scale the beam remains pointed at the satellite, but may sag slightly while the 4 bolts are loose.

Elevation and offset angle.

1. The large circular polarisation scale plate on the back of the wedge shaped box behind the dish is at right angles to the beam. Apply an inclinometer directly. When this plate is vertical the beam elevation is horizontal towards the horizon, elevation = 0 deg.
...
The shape of the wedge shaped box (18.5deg)compensates for the offset angle (18.5deg).

2. If you set the front face of the dish vertical and the feed arm at the bottom, the beam elevation angle is 18.5 deg upwards.  Apply inclinometer to side rim of dish or to strip of wood placed up the front and it will read zero.  To get 41 deg elevation, tip the dish a further 22.5 deg backwards.  

Best regards, Eric.
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« Last Edit: Aug 15th, 2010 at 7:56pm by Admin1 »  
 
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wigglyamps
Ex Member


Reply #4 - Aug 15th, 2010 at 10:39am  
Eric,

On day four now, really got better things to be doing with my time!

My Lat/Long is 31.48N, 65.86E.

Angles to be used are Az 225.8, El 41.2, Pol 39.2

Only found out about 18.5 offset last night.  So does that mean my elevation using the paper inclinometer is now 22.7?

Tried all variations of polarisation, moving dish, moving lnb.  No change.

Have looked at another setup (W7, same equipment) and they're polarisation is 39 on the big scale, ie not rotated to 90 and then back by the required amount.  Still a bit unclear on this.

Got a SAT Meter today, connected using all variaions used over the last 3 days but no joy. 

Starting to believe either we have built the whole thing incorrectly, or there is a fault with the equipment.  Not sure if there is such a thing as 'dead spots' when it comes to Sat Sigs is there??

Yours in desperation,

Dave
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Eric Johnston
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Reply #5 - Aug 15th, 2010 at 11:54am  
Finding a satellite

Quote:
Only found out about 18.5 offset last night.  So does that mean my elevation using the paper inclinometer is now 22.7?

When you apply the inclinometer to the rear side of the wedge shaped box the reading on the inclinometer is  the beam elevation angle. The offset angle is already corrected by the shape of the wedge shaped box. Like so:
...

You only need to know about the 18.5 deg offset if you have the feed arm at the bottom and are applying the inclinometer to the front side edge of the dish or to a strip of wood up across the front face. In this case when the front face of the dish is vertical the beam elevation is 18.5 deg and to get a beam elevation of 41.2 deg you would tilt the front face backwards 22.7 deg.  This is the normal procedure for older dishes that have no wedge shaped box and no circular polarisation scale on the back of the wedge shaped box.  

Try and get the elevation set accurately and then swing the dish boldly sideways.  You will get a reading on the modem/PC and/or on a signal meter.  The satellites are in a curved sloping 39 deg line. It is likely that you find the wanted satellite.   Peak up on whatever satellite you find.  The wanted satellite is most likely the one you have found, or the next either way, up left (towards south) or down right (towards west).
...
Once you have found any satellite note the scale readings so you can always get back to that starting satellite and then move from there.

Getting the wanted carrier - getting a reading above 30

The modem will not lock to the wanted carrier (and go above 30) until you are pointed at the correct satellite and have correct polarisation, LNB tone, frequency and symbol rate.

Regarding polarisation.  If the required receive polarisation is vertical then follow my instructions above.
Regardless of my instructions you can turn the polarisation scale all the way round and there will be two perfect positions.  These positions will be be approx +42 deg clockwise from two of the four quadrant starting points.

With the feed system assembled like this and the feed arm at the bottom:
...
This is horizontal receive polarisation.
Turn the dish 180 deg so the feed arm is at the top. You are still pointed at the satellite and horizontal polarisation.
Turn the dish 90 deg either way and the feed arm is at the side.  Either side gives Vertical polarisation.
None of these starting positions will work as in each case you will have too much interference from the opposite polarisation.  Turn the dish clockwise by 42 deg from any of these positions.  Two options will work perfectly, two will give the wrong polarisation. ( I suggest an adjustment of +42 deg clockwide rather than +39 deg clockwise since the satellite itself my be tilted 3.5 deg clockwise and people have reported better results with between +3 and +6 deg clockwise added.  The hub may ask you to make minor adjustments either way to optimise your polarisation isolation when transmitting CW.  Such minor adjustments may be made at the feed, which is why the limited 5-0-5 range was marked there. )

Modem and LNB config.

Are your frequency and carrier symbol rate set ?.

The Universal LNB PN 1501882-0002 has two local oscillator frequencies controlled by tone.   Follow instructions from Bentley Walker regarding Tone ON/OFF and LNB type.  The text content of the SBC.cfg file affects the LNB pull down menu: e.g. Pure, Universal, 1501882-0002 etc.  

Note that choice of Local oscillator frequency will affect your meter also.  If you connect your meter direct to the LNB then the meter tone will control the LNB local oscillator setting.

Having the modem/PC near the antenna helps.  If you involve a meter, the meter is very convenient as it is readily portable but you have a whole new learning curve and uncertainties in use of the meter. Meters are ideal for people whose work is regularly pointing at the same satellite each time.

Best regards, Eric.
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« Last Edit: Sep 15th, 2010 at 12:10pm by Admin1 »  
 
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deathnova
Ex Member


Reply #6 - Aug 16th, 2010 at 5:13am  
Eric,

Off the top of my head the W7 Cagliari site is 22kHz "Off" with LNB "Universal" (uses a different SBC.cfg than the Turin site, there is no Pure option).
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« Last Edit: Aug 16th, 2010 at 9:06am by Admin1 »  
 
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ShareUrKnowledge
Ex Member


Reply #7 - Aug 17th, 2010 at 10:11am  
Hi,
That's right, for W7-Cagliari, 22K switch is OFF and for LNB type select 'Universal' if you have the universal lnb.
Yes, the 'sbc.cfg' file is different to the Turin site.
Regards.
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ShareUrKnowledge
Ex Member


Reply #8 - Aug 17th, 2010 at 10:27am  
HX W7 (Turin or Cagliari):
RX is vertically polarized so your polarization should be 50.8 degrees and not 39.2.
Regards,
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solideo7
Ex Member


Reply #9 - Sep 14th, 2010 at 10:30am  
Do you have a picture of any of your equipment? Do you have the newer LNB (i.e., the one without the 505 on the horn?)

I just set up an HX50 out here in RC_East. I'm out at FOB Joyce, between J-bad and Asadabad.

I'm not sure what the deal was, but I do have quite a bit of mountains on both side of the my FOB. So, using the original settings from sat-sig for the W7 satellite didn't work for me. So, what I did was set the correct polarization. Then I went a few degrees above the suggested elevation. Then, I literally swept back and forth across the southern sky. I would do this by sweeping back in one direction, lower the elevation slightly, then sweep back the other way.

I know it's a tedious answer, but it was the only way I could get a signal. I did pick up one signal that peaked at 29, I think that was probably the W6.

Not the most technical answer, but it got me up and running. Smiley
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