Signal Distortion - Is this a skew problem?

[KJ6EO]

Could someone tell me what's happening to my signal (example.mov) attached. This clip is from SatMex 8 (116.8W 3815/H/3600). Channel scans as "footschool" but is actually VX "Video Exitos". I've tried moving the skew on the LBNF back and forth a degree or more but it has no effect on the problem. Any thoughts you might have would be appreciated!

 

[Babadem]

What is the quality level, and FEC on this transponder and what Receiver are you using? Is this a DVB-S2 signal?

 

[KJ6EO]

What is the quality level, and FEC on this transponder and what Receiver are you using? Is this a DVB-S2 signal?

Quality Level varies between 50 - 75%. FEC 3/4, DVB-S2 (8 PSK). Receiver is a MicroHD

 

[FaT Air]

Try, while watching the Quality, 20 or more degrees skew adjust. May have to change it a little, wait and watch, repeat. Then in the other direction. "Right On' would be half way between some equal, but low, Quality readings.
Coming in fine here on the S9. Q ~40, hopefully someone with another micro takes a look at that TP.

 

[T4Runner]

I had to enter the freq info manually to match your situation. 7.5ft mesh with a MicroHD getting 35%, but it's jumping the signal quality. It's an DVB-S2 (8PSK), 3/4 FEC
Plays fine. Steady and clear no pixilation. I'm in central CALIF.

?i have not peaked this dish yet. Still needs adjusting.

 

[KJ6EO]

Thanks for the suggestions. I'm gonna take a picture of my LBNF with the dish at true south. Right now i can only go a few degrees +- before I loose the TP. This is my first big dish, so I just rotated the LBNF around till I started receiving stuff. There's a good chance I could have it set up wrong.

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[SatelliteAV]

Channel is playing fine on the test bench units.

SQ 52% and steady. 7.5ft Sami with test unit C-band PLL LNBF. Northern California / clear skies and no forest fire smoke today!

 

[mmewrench]

Thanks for the suggestions. I'm gonna take a picture of my LBNF with the dish at true south. Right now i can only go a few degrees +- before I loose the TP. This is my first big dish, so I just rotated the LBNF around till I started receiving stuff. There's a good chance I could have it set up wrong.

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If you can only go a few degrees either way with your skew, you have other problems (10 degrees should only change quality by a few points). It is more likely your focal distance that is off, or possibly elevation. What type of lnb/lnbf are you using?

 

[KJ6EO]

Picture of LBNF!

I'm using a WSI NS741 (dual band) LBNF. I've attached a picture to this post. The position in the picture is on the 116.8W (Satmex 8). I slid the button hook in and out to optimize the signal strength. The F/D setting was very close to the original position of the dish when I bought it (is now 1/8" closer in). The current position of the LBNF is about 45 degrees, 90 degrees being true north.

 

[FaT Air]

Appears you've 'covered all the bases' with the LNBF.
The only things left are the accuracy of tracking the arc and the LNBF itself.

 

[T4Runner]

You may need to check the scalar ring to ensure it is parallel to the center dish face, and centered properly to ensure you are collecting 100% of the signal. I need to do that on one of my C Band dishes.


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[KJ6EO]

Thanks for all the information. I popped the cap off the end of the LBNF today and had a look to see where the probes were. With the dish parked at true south, the vertical probe is inline with true north/south. The other probe is 90 degrees out from true north/south. Standing in front of the dish, the vertical probe would be at 6 o'clock, and the horizontal probe would be at 9 0'clock. So looks like the LBNF is setup correctly. I slid the button hook in and out and tuned for maximum signal (on a weak TP). As most of you know, the Pinnacle is a very deep dish F/D: .278. I don't know if the WSI NS741 LBNF that I have is capable of fully illuminating the entire surface of the dish. I moved my small dish away from the BUD and allot of my signal problems went away. I think signals were scattering off the BUD to the small dish, and vice versa.

 

[mmewrench]

T4 is absolutely correct. I used a laser pointer on mine to center it. Put a plug in the feedhorn with the pointer in the middle. Rotate it to see where it it points and go for the smallest circle. once you know you are centered there, tweak the dish. Its a pain in the butt, but remember that this dish was originally installed in the analog days. Analog was very forgiving. I think I told you in an earlier post to peak for Ku and C band would be in the bag.