Trouble shooting Freeview Satellite reception

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CutCutCut

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#486176 26-Jun-2011 19:30

illicit: Depends on the initial install - If done correctly, then no, it shouldn't move unless there is a tornado or something.

But lots of installs aren't done very well, sky installs are a common one - screwing the dish to the fascia/barge board instead of somewhere solid, allows flex in the mounting and over time can pull the fascia or barge board off.

like this....

Right, that makes sense. Ours is attached to the chimney, should be pretty solid. It must've moved in the last 2 years as that's when we moved in. I'm assuming the previous owners were using it ok as they had a tv and the install had left the sat dish the only conection in the house.

openmedia

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#486210 26-Jun-2011 21:09

I resolved my issues by swapping the Sharp Qual LNB for a decent one from freeviewshop.co.nz. They also provide brackets for adapting existing sky dishes to take LNBs.

I've now got perfect reception on SBS as well as freeview.

Generally known online as OpenMedia, now working for Red Hat APAC as a Technology Evangelist and Portfolio Architect. Still playing with MythTV and digital media on the side.

CutCutCut

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#486603 27-Jun-2011 21:47

So I turned on the sat box again tonight to have a fiddle and now, One, 2, U, TVNZ7 are working fine. Seem to have Signal 80 and Quality 89 +/- I can't seem to tune in the other channels though, the 12456 MHz ones I believe. Just doing a bit of reading, is it possible that I may just need to twist the actual LNB a fraction and try that?

mm1352000

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#486621 27-Jun-2011 22:20

Certainly, that is possible. There are 4 common adjustments you can make on a satellite dish:

1. Dish left or right.
2. Dish up or down.
3. LNB angle (AKA skew).
4. LNB in or out (closer to or further from the dish face).

CutCutCut

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#486622 27-Jun-2011 22:23

mm1352000: Certainly, that is possible. There are 4 common adjustments you can make on a satellite dish:

1. Dish left or right.
2. Dish up or down.
3. LNB angle (AKA skew).
4. LNB in or out (closer to or further from the dish face).

Right, is there any of the above that would be worth trying first given that half the channels work already?

mm1352000

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#486629 27-Jun-2011 22:36

Definitely the last two. In some cases LNB skew adjustment can be critical to within 5 mm so make small adjustments.

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kiwisat

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#486693 28-Jun-2011 07:46

if you can receive TV1 etc on 12483 Mhz then TV3 etc on 12456 Mhz should not be an issue. Skew of the LNB is unlikely to resolve your problem. I would first check that TV1 is actually being received on 12483 Mhz as it is more likely the LNB LO (local oscillator) has drifted off spec. Very common with Sky 10750 Mhz(LO) LNB's and is known to cause some issues such as you are experiencing.

Paul

Jaxson

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#486788 28-Jun-2011 11:20

As above, what type of LNB have you got? If it's an old ex SKY oval 10750 one then that may be your problem right there.

Re Skew optimising, a budget/rough way to help with this is to turn the lnb one way until it stops giving a picture. Mark this point with a pen. Then turn it back towards where it was and keep going in the other direction until you don't get a picture again. Mark this point with a pen. The optimum is roughly half way between the two points. Using SBS as your target channel will help pinpoint this more accurately too.

CutCutCut

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#487167 28-Jun-2011 22:00

Yup, those channels on 12483. Yes it's one of those oval shaped 10750 Mhz LNBs.

Sounds like it's worth a go thanks Jaxson. I'll wait for some drier weather and get up there and give it a go.

kiwisat

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#487190 28-Jun-2011 22:34

If you do a manual scan at 12456Mhz, Horizontal, Symbol Rate 22500 and get nothing then you could try changing 12456 say 5 steps either way to 12451 or 12461 and see if you get anything then.

And while in that part of the setup menu try 12671 H, 22500 SR.

I can say with near certainty that it will not be your skew, otherwise you would not be getting TV1.

If nothing on any of those those frequencies then I would look closely at your cable runs and connections.

If you can get hold of a cable that you can run temporarily from dish to receiver then that can be a good start.

Paul

CutCutCut

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#488682 2-Jul-2011 21:00

I haven't had a chance to try the above solutions, but now channels 1,2,6,7 are being quite flakey. They were working fine up until last night and then it's patchy. Sometimes they will work and sometimes they don't. Does that sound like the LNB is dying? The wind has been blowing a bit today. Hmmmm

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CutCutCut

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#509918 22-Aug-2011 13:15

kiwisat: If you do a manual scan at 12456Mhz, Horizontal, Symbol Rate 22500 and get nothing then you could try changing 12456 say 5 steps either way to 12451 or 12461 and see if you get anything then.

And while in that part of the setup menu try 12671 H, 22500 SR.

I can say with near certainty that it will not be your skew, otherwise you would not be getting TV1.

If nothing on any of those those frequencies then I would look closely at your cable runs and connections.

If you can get hold of a cable that you can run temporarily from dish to receiver then that can be a good start.

I forgot to update this, but the above did infact work. I used 12461 and added 5 to the other freq and now have all freeview channels tuned in. Why does this work? Is the LNB slightly off somehow? I'm hoping that I'll still be able to use DVB-S in a WMC.

RunningMan

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#509920 22-Aug-2011 13:24

CutCutCut: I forgot to update this, but the above did infact work. I used 12461 and added 5 to the other freq and now have all freeview channels tuned in. Why does this work? Is the LNB slightly off somehow? I'm hoping that I'll still be able to use DVB-S in a WMC.

It means the LNB is dieing - the local oscillator (LO) frequency has changed slightly from it's specified value (probably 10750).

CutCutCut

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#509939 22-Aug-2011 13:51

Ahh I see. I wonder how long it will last...

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