Huge difference between 28.2 and 28.5, what can i do?

summerbreeze · 18-04-2009

Hello everyone again.
In Altinkum- Turkey, i have a 5 metres dish and i can get signals from 28.2 without any problem(sometimes itv's signal go very low tho)
But i cant get any signal from setanta sport in night time. Its on eurobird 28.5. When i search the channels in the morning i can find channels from setanta but in night time no signal. Only 0.3 degree make a big difference.
What is ur advice to me? What can i do then?

**satelliteman** · 18-04-2009

It's due to the very narrow beam width of the dish. Alignment has to be peaked on one or the other, not a problem with a small dish of course.

**Robbo** · 18-04-2009

Yes, the beamwidth of your dish is approx 0.36 degrees, so when focussed on 28.2, you will have less gain for 28.5. Perhaps some sort of actuator could be used to move the dish slightly when switching between the sats.?

***Huevos*** · 18-04-2009

Have you got the LNB skewed for Astra 2 or Eurobird 1. There's 7 degrees skew difference between those two.

**Topper** · 18-04-2009

Originally Posted by Huevos

Have you got the LNB skewed for Astra 2 or Eurobird 1. There's 7 degrees skew difference between those two.

I think you are mistaken the satellites are only 0.3 degrees apart, how can the skew be more?

***Huevos*** · 18-04-2009

Topper mate,

Astra 2 is an oddity; it is skewed 7 degrees clockwise in relation to the equator.

**satelliteman** · 18-04-2009

Originally Posted by Huevos

Have you got the LNB skewed for Astra 2 or Eurobird 1. There's 7 degrees skew difference between those two.

Not sure that info is correct

**Robbo** · 18-04-2009

I believe him, SMM.

_http://www.ses-astra.com/resources/pdf/en-shared/technical_support/Polarisation_and_Frequency_Allocations_1_0_0.pdf

Not only is it just Astra 2, but Astra 1 and Astra 3 according to the document, all of them Skewed by 7.5 degrees.

Dishpointer agrees.

***Huevos*** · 18-04-2009

Originally Posted by satelliteman

Not sure that info is correct

Skew for London (51.5, -0.126)...

Dishpointer:
Astra 2A/B/D = -13.2°
Eurobird 1 = -20.9°

Satlex:
Astra 2A/B/D = -13.6°
Eurobird 1 = -20.86°

If you use a program such as SMW Link it calculates 28E seen from London as -20.9, yet if you go to SES Astra's site and download the support documents they list the skew for London as -13°.

summerbreeze · 18-04-2009

I have a quality sharp lnb i think it is 0.3 db. do you know any better lnb for getting better signals?

even we move the dish 1 mm, all channels go scrambled or no signal. it is very sensetive for where we are (altinkum-didim, 100 km north of bodrum)
I know a bar they have a dish like mine but they have no problem. they have both setenta and skysports. I heard they went to İzmir and bought an equipment and put in front of the dish but they dont tell me what it is..

another thing, i want to thank you all, u all are very helpful people.
I will check my lnb, cable and other equipment and i hope we find a way to sort this out

**satelliteman** · 18-04-2009

See where your coming from now. The ease of installing in the UK, lol

**Topper** · 18-04-2009

Ok thanks for that Heuvos, it seems like a dumb idea to me as it immediately goes against all the principles of satellite transmission theory and makes it difficult for people with polar mounts and H-H setups in fringe areas. Folks in fringe areas would be better using the old fashioned lnb's with co rotors (whatever they were called) to get good reception on 28.2/28.5 respectively, I can though now begin to understand why my sky setup suffers a lot from signal fade on Eurobird when heavy cloud is building in the south East as the skew is a fixed preset amount with a sky dish but in reality the skew required for Eurobird is more than the preset .

I have to say though, re-reading that pdf file, I am still not convinced 100% why would they build in 7.5 degree offset as it would almost prevent them using the satellites in a westerly location unless it is electronically configurable

**Ratchet** · 18-04-2009

Originally Posted by Topper

Folks in fringe areas would be better using the old fashioned lnb's with co rotors (whatever they were called)

I was a fan of the magnetic polariser before the days of Universal LNBs. The abilty to set individual skew per channel was ideal for motorised systems. The skew of an all-in-one Universal LNBF is always going to be a compromise in my opinion. I find it best to tweak it on 1.0W on the TP's in the FSS range that have both H and V signals, e.g. 12607 V/H. I try to get both at the same signal quality as they should (in theory) be the same power. I use other double polarity frequencies in the range as a sanity check.

***trigger*** · 18-04-2009

I´ll go have a play with a couple of big dishes here tomorrow and report. Thinking about it now even with 5 pints of Magners on board, the few dishes I look after on Eurobird do seem to be skewed further round. Possisbly - maybe

Get back to you tomorrow

summerbreeze · 18-04-2009

Well, the dish is 4 metre parabol dish (4 year old)
The LNB is Invacom 0.7 db flanch
and its not possible to watch ITV and Setanta at the same time. No way

You have to pick 28.2 or 28.5 or buy another dish lol

**satelliteman** · 18-04-2009

Originally Posted by trigger

I´ll go have a play with a couple of big dishes here tomorrow and report. Thinking about it now...... even with 5 pints of Magners on board, the few dishes I look after on Eurobird do seem to be skewed further round. Possisbly - maybe

Get back to you tomorrow

oh, have I missed the party

***Huevos*** · 18-04-2009

Originally Posted by Topper

I am still not convinced 100% why would they build in 7.5 degree offset as it would almost prevent them using the satellites in a westerly location unless it is electronically configurable

I don't see what you are getting at here. If later for some reason the satellite was required back in conventional orientation the stabilization system would be used for that, after all that is what is holding it at any particular angle.

Originally Posted by summerbreeze

I have a quality sharp lnb i think it is 0.3 db. do you know any better lnb for getting better signals?

Here that's very a well respected LNB, although no longer available.

Originally Posted by summerbreeze

Well, the dish is 4 metre parabol dish (4 year old)
The LNB is Invacom 0.7 db flanch

Which dish? I thought you said yours was 5 metre with Sharp LNB.

***trigger*** · 18-04-2009

Originally Posted by satelliteman

oh, have I missed the party

Nah its the weekly Five on Friday - LOL

summerbreeze · 18-04-2009

Originally Posted by Huevos

I don't see what you are getting at here. If later for some reason the satellite was required back in conventional orientation the stabilization system would be used for that, after all that is what is holding it at any particular angle.
Here that's very a well respected LNB, although no longer available.Which dish? I thought you said yours was 5 metre with Sharp LNB.

I am sorry. it is 4 metre and not sharp. I thought it was sharp and 5 metre but my mistake. i bought this equipment from a friend.

***Huevos*** · 19-04-2009

Originally Posted by summerbreeze

I am sorry. it is 4 metre and not sharp. I thought it was sharp and 5 metre but my mistake. i bought this equipment from a friend.

Which Invacom is it? Can you post a photo? I've got a QDF-031 (C120-quad) on my dish but nothing to compare it to. All prime focus dishes here either have this LNB, an obsolete Sharp, or a modified Darkgold which are super sensitive but only single port.

By the way if you have a 4 metre dish and the bar has a 5 metre then the has 56% more dish surface which is going to make a black and white difference.

**kamaleon** · 26-04-2009

Hi Huevos,

Say what do you mean by modified darkgold? You mean the feed cut off? Got any pics of that m8?

Cheers

***Huevos*** · 26-04-2009

Originally Posted by kamaleon

Hi Huevos,

Say what do you mean by modified darkgold? You mean the feed cut off? Got any pics of that m8?

Cheers

I was having a blonde moment. It's not a Darkgold, it's an Inverto Black Ultra.

**kamaleon** · 26-04-2009

wow just look at that, really strange mod!! Does that perform better than the inverto white tech C120?

***Huevos*** · 26-04-2009

Originally Posted by kamaleon

Does that perform better than the inverto white tech C120?

I haven't compared them.

This modified LNB is only available in a single. In a twin or quad install I'd use an Invacom, but for a single I'd choose this. C/N is brilliant.

I've been experimenting with my 1.5 metre dish lately. I removed the Invacom quad and the CM feedhorn and put a Darkgold single. C/N was marginally better according to my Satcatcher and I'm getting better quality on Astra 2D and have picked up a couple of extra transponders. Still only getting verticals though so can't say how they compare on horizontals.

**kamaleon** · 26-04-2009

So you're actually saying this lnb is actually sold like that? care to disclose more details?

I think you keep mistaking the inverto black ultra with the darkgold, which are completely different lnbs btw

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