Usals problem & alignment

[Red alert]

Have you checked that your LNB is sited correctly, by sliding it back and forth?
I still think you might need to do some gentle tweaking, unless you have obstructions, at 39E and 42E, blocking the signal.
Try to ignore the dish bracket information, this is usually just a guide, and try adjusting your motor angles, slightly, then compensate by adjusting your dish bracket, to peak the signal quality, on 0.8W. But always make a note, of where they currently are, so if it gets worse you can quickly move it back again.
Then check the signal quality readings, on the satellites.

Yeah LNB is checked and works best when pushed back. The weird thing is when i very slightly change the elevation on the motor it doesnt have much effect on the results. With most declination settings either up or down a few mm i notice 26 east always needs to be pushed slightly to the right. So when it comes to moving the motor mount a few mm to the right when motor is at 0 then signal quality goes down on all other sats. I also tried using 5 west also to align dish/mount and noticed a very small improvement across 5 west to 23.5 east, but nothing on 26 east. I can only pick up 1 freq on 26 east. Also when i change declination on motor i notice moving mount left/right doesnt make difference to signal quality on 1 west. Would there be a difference if i align dish on 5 west rather than 1 west?

 

[Channel Hopper]

You must push the dish up/down using the rear of the mount (or pull/push the pole), if you use the boom arm or the reflector edge this will give you false readings

 

[Red alert]

You must push the dish up/down using the rear of the mount (or pull/push the pole), if you use the boom arm or the reflector edge this will give you false readings

I have been using the boom arm just close to lnb to raise and lower the dish once i loosen the bolts. So basically use the dish mount bracket to lower and raise the dish without touching the lmb arm?

 

[Channel Hopper]

Nothing in front of the mount since it changes thhe geometry of the dish

 

[jeallen01]

You must push the dish up/down using the rear of the mount (or pull/push the pole), if you use the boom arm or the reflector edge this will give you false readings

Agreed, but it does give you an idea of whether it's pointing anywhere very close to a sat and then in which direction the overall dish elevation needs to be adjusted.

 

[Red alert]

Hi all, just figured out what the problem with the setup was. Its how the lnb sits in the holder. By slightly tilting the lnb up signal increased across all sats by 15-20% (by the way i didnt push up the lnb arm, just the lnb). Not sure why this has happened. Its like the lnb is not quite central to the centre of dish. Not sure if prob with dish face or lnb arm as the cause. I have had to use insulated tape to secure the lnb at the optimal position. Maybe lnb issue. Its a inverto single black ultra lnb. Seems it dont sit in the lnb holder very well. Im very close to getting good signal across the arc. What do you guys suggest i should do Next?

signal on 0.8 west is 85% up from 70% previously.

 

[a33]

What I would do?
Assuming the dish has a flat face: measure hight, width up to a mm precise and depth at the middle to some tenth of a mm precise, and put those values in a calculator (e.g. my own) to calculate exact position of the focal point, and where on the dish the LNB should aim.
And of course, do a string test, to check if the dish isn't warped.

Or have you done all that already?

BTW, Is that the original LNB holder? That it needs tape, already?

greetz,
A33

 

[jeallen01]

I have no problem with the Inverto Black Twin on my Gibby OP 125L but that's got the V-shaped twin feedarm config, whereas your has just a single arm dish - so it seems to me that would mean that the LNB end of the arm is too high as that would cause the LNB to be aimed too low on the dish face.

So, have you checked the arm fixings behind & below the dish face to see if they look to be correctly aligned/bolted up? If they are then it would appear that the arm &/or LNB holder was either badly manufactured or slightly bent "upwards" thereafter. I would "favour" the LNB holder as the one on my dish very firmly clamps the LNB at (what appears to be) the "correct angle".

OR, maybe the supplier made up a "bitza" dish & arm set (CH mentioned that the Gibertini supplier in Harlech is known for doing that!) - and included the wrong LNB clamp? Where did you get it from?

 

[sonnetpete]

It looks like the correct LNB holder for a Gibertini XP, as it's identical to mine. However, the holder should slide onto a clamp on the LNB arm and be secured with an allen key. Check that your LNB arm has a plate on the end over which you can slide the LNB holder. If not and you have to steady it with tape, the holder either isn't fitted properly or the 'dealer' has substituted a different arm to the dish face.

 

[sonnetpete]

Here's two photos of the holder. If I can dig out the dish, I'll try and photograph the arm tomorrow..

 

[jeallen01]

@Red alert
Can you post a close-up of the LNB holder and LNB on the feedarm - but without the tape?

 

[Channel Hopper]

@Red alert
Can you post a close-up of the LNB holder and LNB on the feedarm - but without the tape?

He might lose everything if the black tape comes off, anthracite dish. grey feed = Alarm Bells

 

[jeallen01]

He might lose everything if the black tape comes off .

Maybe, but now he knows how to "temporarily" fix the LNB problem - and maybe he has some shots of what it was like before he did "fix" it?

 

[Red alert]

here are the photos i found from a while back. Not a close up but until I remove the tape for better photos i hope the attached will suffice. I purchased the dish from hm-sat-shop. The lnb holder clips onto the front of the feed arm plate similar to that posted by sonnetpete but not quite, the screw is on the other side and closes at the top rather than the side.

i can check to see if dish is warped in any way using the string method, not tried that so will read up on it @a33

i have checked the fixings behind the arm and they seem to fit well.

 

[jeallen01]

He might lose everything if the black tape comes off, anthracite dish. grey feed = Alarm Bells

"bitza kit" combo of dish, arm & LNB holder seems likely!

 

[sonnetpete]

I can't imagine HM Sat selling something made from 'bits'. It's possible certainly but everything I've had from them has been spot on. My photo's are a bit misleading as the LNB holder is back to front. However the holder is made of alloy and I know the clamp can become hard to tighten. I'd take the holder off, give it a spot of oil on the moving parts and make sure it tightens up before re assembly. From memory, the mount on the dish arm is riveted to it. The rivets may have come loose so that's worth checking too...

 

[a33]

Its like the lnb is not quite central to the centre of dish.

Only with a prime focus dish, should the LNB be pointed to the center of the dish.

With an offset dish, it should be pointed below the center, even below the deepest point!
Namely along the bisector line, from focal point, dividing the angle between top and bottom of the dish exactly in halves (or maybe a little little bit higher, that would also be acceptable).

Greetz,
A33

 

[sonnetpete]

Here's the photos of the LNB mounting plate on my Gibertini XP....

 

[Red alert]

Here's the photos of the LNB mounting plate on my Gibertini XP....

Mine looks like that also. The lnb holder then clips to the front and i tighten it with allen key. Is there something else that clips in the 3 holes at the front. Or just the supplied silver lnb holder. what lnb are you using @sonnetpete ?

images of back of dish where lnb arm connects is attached.

 

[sonnetpete]

My XP is currently 'mothballed' (or cobwebbed) but when it was part of my multi sat setup, I was using a single Black Ultra... Mine attaches exactly as you've described and there's nothing on the mounting plate you can tighten, it's pop riveted to the arm. (I suppose it's possible that that's loose but I doubt it). Have you taken the LNB off and checked if there's movement of the mounting plate? Other than that, I'd take the clip part of holder apart and oil the clamp. Make sure it tightens all the way before putting it back on the dish.

Incidentally, I found that the LNB worked best when positioned fully forward (i.e. towards the dish face).