Problem with LNB polarity

Johnmorrin · 05-09-2008

Heres a few pics of my humble set up.

Im trying to pick up W3A 7e for broadsat sattorrent internet.I have an 80cm lidl dish hooked up to a Skystar2 pci card.The best signal that I can get is 63% quality and 8db SNR. I can only pick up this signal when the LNB's skew is at around 80 degrees (See pictures) Transponder settings are

11262Mhz
Frequency : 1512mhz
Symbol Rate : 27531kS/s
FEC : 3/4
Polarity : Horizontal/Left (High)

I was told that because the transponder is Horizontal that this is why my LNB has to be at such an extreme angle, Is this correct ? Also I get a lot of rain fade and signal drops to around 40% and SNR of 6 - 7dB and I start getting BER readings.

Anyone any Ideas what can be done ?

**rolfw** · 05-09-2008

No, your LNB should sit slightly off the vertical at about 7 o'clock as you look from behind the LNB towards the dish, what are your satellite and LNB settings for your Skystar card, have you set the LNB to Universal with voltage switching for polarity? Can you receiver the channels on 11283 V like M6 Suisse?

Johnmorrin · 05-09-2008

The Skystar settings are the ones that I have posted.

**rolfw** · 05-09-2008

There should be more basic settings like switching frequency, LNB type etc, but in any event, the LNB needs to be set as per my picture above.

Johnmorrin · 05-09-2008

Yeah I realise the LNB should be the way you illustrate , but what i cant figure out is when it is vertical , there is no possible way that the skystar will pick up the transponder that I need.Here is a screencap from the Skystar2 control panel

**rolfw** · 05-09-2008

There is another panel of settings, it'll show the type of LNB and switching settings.

But you didn't answer my other question, can you get M6?

Johnmorrin · 05-09-2008

OK I think I found it.The settings that are there are the ones recommended by Eutelsat though. How would I go about getting M6 ?

**rolfw** · 05-09-2008

Have you installed the TV viewer?

there should be another setting which decides the type of LNB.

Ratchet · 05-09-2008

To get a horizontal signal with your LNB in that position implies that your card isn't sending the required voltage to switch the polarity. Are you able to get any vertical transponders with the LNB in that position ? There is a strong vertical data transponder at 11351 with a SR of 8571. You may have to add it manually as it doesn't appear in Setup4PC by default.

Whilst on the 11262 transponder, what happens if you change the polarity setting to vertical when in 'Edit Transponder' mode ? Note that you have to click on 'OK' for the change to take effect. If nothing happens (i.e. the signal remains) then the card is not putting out the correct voltage to the LNB.

By the way, 63% signal quality with a Skystar 2 is actually quite good. The SS2 is notoriously mean with its signal readings. This would equate to 90% on my other sat boxes.

Johnmorrin · 05-09-2008

Ok I think ive found something.I got back out on the roof , in the pi$$ing rain no less and rotated the LNB back to where it should normally be.Went back inside and the satellite signal was gone , I then changed the polarity setting to vertical , and the sat locked on.Why would broadsat tell me to use the horizontal setting though ?

**rolfw** · 05-09-2008

Don't use dollar signs in your posts, as a new member the spam trap catches them and puts the post into a moderation queue.

Sounds like your LNB commands are incorrect, or the LNB polarities are reversed.

That's why I want to see the LNB setup menu, it should be 13v Vertical and 18v Horizontal.

**Robbo** · 05-09-2008

It does not apear that they have given you the wrong details, lyngsat only lists a horizontal transponder at that frequency, and I can find no signal with vertical.

**satelliteman** · 05-09-2008

Sounds like your LNB commands are incorrect, or the LNB polarities are reversed.

Yes, I thought that too.

The O/P skew setting it was on compared to the new setting (about 7 'O Clock) is about a 90 º turn which will give the opposite polarity

Johnmorrin · 05-09-2008

OK i read all the manuals for my card , and there is no setting for LNB voltage or polarity.I did a bit of looking on the net and found this :

The power converter on the Skystar2 card who converts the 12V PC voltage of the
13–19V power for the LNB is not overload protected and can easily be damaged by a
shortcut in the coax cable or F connectors or a stalling or heavy turning DiSEqC motor. When
the overload last long enough a coil in the power line becomes very hot and becomes
defective.
This coil has to prevent that the 22KHz tone for the low/high band switching in the
LNB flows into the converter instead of controlling the LNB band switch. With a damaged coil
the level of the 22KHz signal on the coax is depending on the decrease of the inductance of
the coil, so sometimes one LNB will still switch while another one stays at the low band.
Due to the overheating mostly some windings of the coil become shortcut so
decreasing the inductance of the coil. The voltage on the line is still correct, the polarisation
switching controlled by the 13–19V on the line will still work, but the low/high band
switching will fail. So only low band transponders will be scanned.

I wonder is this my problem ?

**rolfw** · 05-09-2008

Could be, but there will somewhere be an LNB setting in the software menu, there certainly was when I used a Skystar.

If you are only using it for that one transponder, then just skew the LNB for the best reception, it could of course be the LNB which is faulty.

Johnmorrin · 05-09-2008

Maybe it was older drivers that you were using ? Dont think its the power converter either , just pulled the skystar from the pc and mine is listed as revision 2.3 and i think its only the revision 2.6 card that has this problem.Yeah im only going to be using this dish , lnb and skystar for Sattorrent so once it picks up that transponder fairly well then ill be happy.Oh yeah , i already tried changing to a different lnb and its still the same.Tried the cable too

**rolfw** · 05-09-2008

How do you tell it what LNB you are using?

Johnmorrin · 06-09-2008

Originally Posted by rolfw

How do you tell it what LNB you are using?

No I changed the actual LNB itself on the dish.

**rolfw** · 06-09-2008

You don't understand, there is more than one type of LNB, so there must be a panel in the software in which you define the LNB parameters.

**Llew** · 06-09-2008

Whilst awaiting a reply from the OP, regarding the difference in SS2 versions -

Revision 2.3 has a fuse (F1) which revision 2.6 singularly lacks. I don't know the reason for this omission, and without it any short circuit in the LNB feed will usually fry the choke.

This happened to me owing to a faulty A/B switch, and I had to rewind the choke.

Pic 1 is the 2.3 board, with fuse F1.

Pic 2 is my repaired 2.6 board

Llew

Johnmorrin · 06-09-2008

Was the problem that you had similar to mine Llew ? Ive checked my card , and its revision 2.3 and looks the same as your first picture that has fuse F1. May check this fuse later with the multimeter.

**Llew** · 06-09-2008

No, not the same problem. My choke didn't open circuit, just a dead short. This allowed H/V switching, but I lost the DiseqC signals, as the choke is there to buffer the DiseqC line from the voltage switching circuitry.

You seem to be having a problem with the H/V switching if I read right, but as Rolf said, unless you can show us a panel that gives the LNB parameters, it's difficult to know what your problem is.

What application are you using? The Setup4PC that comes with the Skystar? Better to use progDVB or another viewer that has an LNB options menu that will give us a clearer picture.

Llew

Johnmorrin · 06-09-2008

Ok This is a screencap of the LNB options in ProgDVB.

**Llew** · 06-09-2008

That's fine, you're set up for W3A using a Universal LNB. It's back to making sure your dish is correctly aligned on the satellite and you are sending the correct voltages to your LNB.

Use a short lead terminated with F plugs to check the voltages at the LNB terminal while switching to a V and H channel (don't short the lead out with your multimeter!)

Johnmorrin · 09-09-2008

Ok I got the problem sorted.The problem was ME , I had it pointed at the wrong satellite

.Guess its one of those newbie mistakes , ive only had the setup a week and still getting to grips with the technical side and all the lingo .Signal is still fairly low , but I think thats because of the crappy lidl dish , one of my mates is giving me a 90cm old sky analogue dish for free on wednesday.Maybe that will help a little with the rain fade and wind.Those lidl dishes are a little flimsy.
Thanks to all those that helped me