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HX50 Help:  AFG   W7

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Ex Member

Mar 31st, 2011 at 6:50am  
We purchased the Dual 4000 system and have been having problems getting the satellites to link up.  The highest we are ever able to get for signal strength is 29.  We have tried moving the dish all over the place.  We have also tried two different set of pointing values, the ones wafa gave us and the ones that are on the sbc.cfg file.  Here is what wafa gave us to use:

Elevation 41.2
Magnetic Azimuth:  226
Polarization 49.1

Here are some other configs:

Satellite Channel Freq:  19588
Receive Symbol Rate: 10000000
LNB Polarization:  Vertical
Transmit Polarization:  Horizontal
LNB Type:  Universal

Any ideas or help would be greatly appreciated as I am getting tired of climbing up and down the roof!

Thank you
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« Last Edit: Apr 4th, 2011 at 8:21am by Admin1 »  
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USN - Retired
Ex Member

Reply #1 - Mar 31st, 2011 at 12:06pm  
Not enough info Benny. Let's start with; where is the dish located (lat/lon)? which satellite are you trying to point at?

Sig strength of 29 is just noise, indicating that the LNB has not yet detected a usable signal. Did you in fact input the specified satellite parameters to the modem? Is your POL angle rotated positive or negative? And please verify that "satellite Channel Freq".

And the *.CFG file doesn't contain actual "pointing values", so I don't quite understand "tried two different set...". Please explain.

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Ex Member

Reply #2 - Mar 31st, 2011 at 12:18pm  
Sorry.  The dish is located 30.59 North and 66.21 East.  We are trying to connect to W7. 

We have uploaded the SBC.cfg file and entered the specific parameters given to us by wafa.  The channel frequency that they gave us to use is 19588 and our POL is positive. 

When we go into the "Installation" menu and then the "set up" portion there is the option "Antenna Pointing".  When we click on that it also has a set of values (elevation, azimuth) that the dish should be using.  They're close to the ones that wafa gave us be slightly different.

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Reply #3 - Mar 31st, 2011 at 2:38pm  
I understand now. The "other" set of pointing angles is not actually in the .CFG file. It's created when you type your lat/lon and satellite location into the modem user interface (Installation/Setup). WAFA may simply have used a slightly different algorithm than does the modem, which explains why the two sets of pointing numbers were not identical. The calculated pointing angles are just starting points anyway, only intended to help you initially obtain the right signal. By the time you're done fine tuning and lock down the dish, you may end up with a third set.

And I got similar Az/El numbers (226.9 magnetic/41.6). The POL number is a bit different (+40.4) but - given the correct numbers were fed into your satellite parameters at setup - the POL discrepancy shouldn't stop you from at least finding the signal.

I'm still however, scratching my head at the Satellite Channel Freq. But since I'm not sure what the LOF is on that bird, we'll have to wait till Eric (site owner) chimes in here. In the mean time, click on the Search link above. Change the number of days from 7 to 99999. Search for "W7 LNB" (no quote marks). It will bring back links to several other members who've needed help with W7

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Ex Member

Reply #4 - Apr 3rd, 2011 at 5:28am  
Looking for an opinion here, . . .

How reliable is the HORIZON HDSM (Horizon Digital Satellite Meter) USB?

Not to be confused with the USB Plus model. We're currently using it to measure our signal strength and it doesn't seem to be giving us a reliable reading. No matter where we point the dish, it gives around 56-58dBu sig. strength.
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Reply #5 - Apr 3rd, 2011 at 1:49pm  
I've never used one personally. But the limiting factor to that type test set is the data base. Assuming it's an otherwise healthy and updated device, it should be perfectly suited for the job. Eric on the other hand, may actually have used one. I'm not sure if he's out of town on business or what. If he doesn't join in soon, I'll shoot off an email with a suggestion to drop in on this thread (I'm in the USA, he's in the UK).

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Eric Johnston
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Reply #6 - Apr 4th, 2011 at 2:02am  
I'm just back from Egypt.

To bennypollok.

Try to get pointed back to the position that gives 29 on the HX modem screen readout.

The scale works in two ranges 0 - 29 is noise power.  30 - 100 is wanted signal quality.  With 29 you are maxed out on a powerful satellite signal. Peak up on the 29.

29 indicates that you are aimed at some powerful satellite.  It is quite likely the wanted satellite, particularly if the elevation angle is about right.  The noise from adjacent satellites will also give readings in the range 0 - 29. The adjacent satellite are in a diagonal line (for you), across the sky, up left and down right .

The problem is now related to polarisation or configuration settings.

If you have the type of antenna with giant circular polarisation scale behind the dish then with the dish rotated so that the feed arm is at the bottom set the universal LNB cable connector so it points out exactly sideways. Check that the 505 on the feed throat is directly away from the feed support arm.
With the feed arm at the bottom and universal LNB connector sideways you are now true Horizontal receive. This is wrong for you.
So, turn the entire dish 90 deg anticlockwise, while behind the dish. You are now true Vertical receive (which is what you say you want). This is your polarisation starting position.
Now turn the dish by an amount of 40.4 deg clockwise.
The amount of adjustment is what matters. The scale may go backwards from 90, e.g. counting down from 90 to 49.6

Check carefully that you have typed in the  frequency and symbol rate as told.
Check the LNB type pull down menu (the displayed text comes from the sbc file). This is important as it alters the selection of local oscillator frequency in the universal LNB.

When you get it working please say here what fixed it.

Best regards, Eric.
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« Last Edit: Apr 5th, 2011 at 5:02pm by Admin1 »  
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