clarke belt

[fromaron]

If someone had an 80cm Austar dish, and it was tracking the Clarke belt correctly, Would it be reasonable for him to expect to get a usable strength signal from satellites other than the 4 mentioned by gcguy?.
ie:C1, D1, D2, Intelsat8.

Ok BlackDuck, I'll try to clear few things here.
When I say I am tracking every single satellite available in my location I mean my dish positions correctly to receive the signal from every one of them. That means as I have only single LNB setup I can receive very good quality from all but Optarse ones. When it comes to Optarse birds I can receive only few channels with maybe 25% - 40% quality only because my LNB is set to the Clarke Belt theoretical skew (0 degrees LNB angle at true North or 0 degrees dish position).
To get all of them at maximum quality you need to do what beer4life was suggesting - two dishes or two LNBs on one dish skewed differently.
So my point is - there are two aspects to h-h positioner alignment (thanks to Optarse):
1. Dish correctly tracking the Clarke Belt;
2. LNB is correctly positioned to receive Verticaly and Horizontaly polirised signals.

To answer your second question, my h-h positioner correctly tracking the Clarke Belt and positions my dish in a right spot to receive signals from all satellites between 180E (55 - 65 % quality) and 95E (~80 - 90 % quality) providing something is transmitted in ku band to my house.

[beer4life]

Methinks you did not fully understand my last post.
You cannot get all Satellites on the Clarke Belt at maximum quality with a H - H dish.
The Skew for PAS8 is 40 degrees different to C1, D3, D2 and D1.
With the different Skews of Optus and other Satellites, you can peak the Skew for one or the other, but not both with normal LNBs.
The best you can hope for is a compromise.

Kindest Regards, " The Druid ".

[BlackDuck]

I get at least 1 channel on each of the afore mentioned 4 satellites with a sig of 80% or better.

Now if I enter into the Humax manual search the frequency of say 1111, and a SR of say 2222, obviously there will be no satellite that conforms to these settings.

I then sweep the dish from West to East and the bar display indicating LNB status remains at about 25% and the Signal status remains at 0.

Now if I enter the details for a channel on say C1 and sweep back from East to West at approximately a little East of North, I start getting strong signal readings.

So my conclusion is that the Humax requires the information for at least 1 channel on the satellite you are searching for to be entered, before it can find it.

Now before you type Lyngsat, I thought that the people who already have these wayward satellites in their STB could just enter the details, frequency, polarity, SR and FEC, of 1 strong channel on each of the satellites they recieve, except C1, D1,D2, Pas8, and give gcguy and me and others a target satellite to aim for. Name and Frequency wise.

[beer4life]

C'Mon Cobber,
That would take all the fun and sense of achievement if we were to just serve you up Jugged Hare.
To state the obvious, most of what you want has already been researched on Lyngsat including footprints.
It is simply a matter of interpreting the charts.



Kindest Regards, " The Druid ".

[BlackDuck]

C'Mon Cobber,
That would take all the fun and sense of achievement if we were to just serve you up Jugged Hare.
To state the obvious, most of what you want has already been researched on Lyngsat including footprints.
It is simply a matter of interpreting the charts.

After studying Lyngsat, NONE of what I asked is answered there.

And for obvious reasons, Lyngsat don't know what satellites you, fromaron, gcguy or me are actually getting a usable signal from, or what equipment we use to get it.

As this is the Newbie section and I've freely admitted that when it comes to satellite TV, I'm probably more Newbie than most. I thought that this would be the place to ask the questions that a more experienced poster may be able to answer.

[fromaron]

After studying Lyngsat, NONE of what I asked is answered there.

And for obvious reasons, Lyngsat don't know what satellites you, fromaron, gcguy or me are actually getting a usable signal from, or what equipment we use to get it.

As this is the Newbie section and I've freely admitted that when it comes to satellite TV, I'm probably more Newbie than most. I thought that this would be the place to ask the questions that a more experienced poster may be able to answer.

That's alright BlackDuck, nothing wrong with asking questions. Obviously beer4life is right as well as you never learn if you get the straight answer .
I can give you the process to follow in order to pick up the right channel for tracking.
For example you try to get to the first satellite I said I have - Intelsat 701 located at 180E on the belt.
The next step is to go the lyngsat site for example and click on the satellite link. That will open a table with all available frequencies there. As you are after ku band channels, look for the frequencies in the left column greater then 10000. Then from the table you will see a column called "Beam". The beam will give you a map showing area the frequencies can be received.
On that satellite Spot 3 map will reveal the picture:

As you can see people living in the ocean can enjoy all the channels there .

Then you might want to check Beam No.2:

This beam looks better as it covers my home.
Next thing is to check channels with symbol F (Free-to-Air) if you are after viewing it.
For example you want to see channel called LeMouv'. For that you will need to enter 11174 as a frequency, Horisontal as polarisation and 23150 as a SR (symbol Rate).
That's it. Do it for all satellites one by one until you get 1 channel for all birds beaming to your house.

[beer4life]

After studying Lyngsat, NONE of what I asked is answered there.

And for obvious reasons, Lyngsat don't know what satellites you, fromaron, gcguy or me are actually getting a usable signal from, or what equipment we use to get it.

As this is the Newbie section and I've freely admitted that when it comes to satellite TV, I'm probably more Newbie than most. I thought that this would be the place to ask the questions that a more experienced poster may be able to answer.

G'Day Cobber,
You do not fully understand what a big ask your requirements are.
Although we are able to track the Clarke Belt, we would only note the ones that are of specific interest. To collate what you are asking is a prodigious task.
Now, look at the Asia and South pacific page :-
You will see the colours and at the bottom of the page you will see what they mean. Cband, Kuband and C & Ku.
So for a start, no point in looking at the pink ones if you have a Ku Dish only.
Next look at this Sat. It has C and Ku :-
You can see which are the most likely TPs with FTA marked with an F.
They are also marked as to which beam, C or Ku in the second last column.
Also note the TPs with Radio only are in fine print detail.
At the top of that chart, you will see :- .
Click on that will give the Footprint Maps. From that you can see that there is no chance of receiving Ku signals in Australia, but that the C band is possible.
If you go to Dish Pointer, you'll find that from Sydney, the Elevation is only 4 degrees. Very low on the Western Horizon. This means that you would need to be high up or have a clear view to the West.
Now, most of the Satellites have varying degrees of that information. Some are even more detailed with several maps showing the footprints for each TP.

All the information that you are asking us to collate for you is already there.
If you have trouble with interpretation of anything specific, we will be only too happy to assist, but, even if this is the Noobies section, there are limits to spoon feeding.
No offence intended, but I hope you accept this advice in the spirit intended.
Many others do not have Blind Scan STBs, but they manage using the above information. It would be hard to beat a Strong for price and features.
Kindest Regards, " The Druid ".

[BlackDuck]

Somehow the Simplex has become Complex.

beer4life, I don't want you or fromaron to collate anything for me, I somehow, erroneously apparently, thought that you or fromaron may have had a list of the sats that either of you had received on an 80cm dish.

Looking at Gorbtrak KU there would seem to be a maximum of about 12 or 13.

If I had settings that I knew worked, I could enter this information into the Humax and sweep the belt, This would show me if I was close to being right on the Clarke belt, or depending if I got some signal at East but not West, or vice versa, would simplify any correction I may have to make to the azimuth.

Thanks for your trouble.
BlackDuck.

[Godzilla]

Interesting discussion.

What would happen if you put a multi LNB holder on the motorized KU setup, one LNB with the ideal skew for the Optus sats and the other LNB with the optimal normal sat skew?

Just thinking out loud, interested in hearing Beer4lifes expert view on the matter.

Actually the more i think about it the more it makes sense to use a polarotor on a prime focus dish.

Do they make these for offset dishes?

[beer4life]

Interesting discussion.

What would happen if you put a multi LNB holder on the motorized KU setup, one LNB with the ideal skew for the Optus sats and the other LNB with the optimal normal sat skew?

Just thinking out loud, interested in hearing Beer4lifes expert view on the matter.

Actually the more i think about it the more it makes sense to use a polarotor on a prime focus dish.

Do they make these for offset dishes?

Great minds think alike.
Check post #39, but I have suggested it before in other threads.

On a Toroidal or multi LNB holder, the LNBs are individually set for optimum skew for each Satellite.

You could of course mount two LNBs on your H to H dish with a DiSEqC Switch to select either for Optus or other Satellites.

How do I get over this anomaly? Easy, I have two H to H Dishes. One for Optus and the other for normal Satellites.

And yes, I have looked at polar-rotators. Not worth the cost for little convenience.

[BlackDuck]

OK, A quite Sunday morning to sit down and try to apply what's been said in the previous posts, Thanks to beer4life and fromaron.

The information from fromaron, re Lyngsat proved very useful as I didn't know that so much additional information was hidden, Just waiting for a mouse click on the appropriate field.

Armed with this extra information I realised that so many of these satellites have got their "Backs turned to us" and as such inaccessible with an 80cm dish. Damn Them!.

I thought that NSS6 to the West should present a good target to a properly aligned dish, signal wise, So I aimed for it, using 12647-V-30000 3/4.

Scanning West I got a small blip which I locked onto and entered as NSS6, but was unable to download any channels.

So from this I conclude that while My dish is close enough to the Clarke belt to get satellites that are close to North, and get Pas8 to the East, My alignment is skewed a little East of North.

I went out and looked at the position of the dish on the position I entered for NSS6, and wow!, the angle of the LNB was almost horizontal.

Thanks for the patience and all the help, I now have an idea where I have to make my adjustments, and yes there's probably nothing on the satellites that I will want to look at, But the buggers are up there so I want to be able to access them anyway.

Thanks again,
DumbDuck.

[beer4life]

Aarrhh, you're back from Church Cobber.

I went out and looked at the position of the dish on the position I entered for NSS6, and wow!, the angle of the LNB was almost horizontal.

That is to be expected my friend.
The mechanics of the H - H Motor are designed to twist the dish and hence the Skew to follow the observed Skew as the Azimuth increases.
This is the reason you must start your set up at True North from your location.
As you go East or West in Azimuth, the observed Skew changes.
Unfortunately Optus, in their misguided wisdom, have chosen to have their Transponders inclined. Methinks to make it difficult to use their dishes for other Satellites.
That, in a nutshell, is why, with a single LNB on a H - H, Skew is a compromise with other Satellites.
I'm pleased that you now know just how much info is on the Lyngsat charts.
Far more up to date than any single person can keep their own records.
Kindest Regards, " The Druid ".

[BlackDuck]

Aarrhh, you're back from Church Cobber.

More things are wrought by prayer than this world dreams of!

John Charles Thomas, Morning devotions, early 1950s radio program...

[beer4life]

G'Day Cobber,
For those that do not understand all the mumbo jumbo about Skew.
This looks more like hen scratching, but may help to clarify why you need to adjust the Skew on different satellites at various observed angles.
For best signal between Tx and Rx, both antennae must be in the same plane. ie: H - H or V - V as well as inclined if viewing at other than directly due North or the Sat itself is at an angle.


If any one is better at illustrating than I, Please do not hesitate to do so.

Kindest Regards, " The Druid ".

[beer4life]

BlackDuck, you Reprobate, carefully digest what is in Lyngsat.

I thought that NSS6 to the West should present a good target to a properly aligned dish, signal wise, So I aimed for it, using 12647-V-30000 3/4.

Even you cannot decrypt MAC TV beam into Australia. It is not FTA!

You should have more success with 12736 V / 3333 SR (Beam into Australia)
NTD TV Asia Pacific
UTR
Faith FM (radio)

Try that and see how you go. It's near the limit of a Universal or 10700 LNB.

Kindest Regards, " The Druid ".

[BlackDuck]

I understand Optus's weird inclination clockwise from the point of view of the observer, I don't understand the WHY, but I know it's there, but I don't understand what you mean by the black lines and their verticality when shown West or East of North.

Wouldn't the skew, from the view point of the observer, seem to be on an imaginary line drawn from the equator North point, bisecting the position of the satellite in the sky?

BlackDuck, you Reprobate, carefully digest what is in Lyngsat.

I never thought I could decrypt the signal, only detect it, I don't know about other STBs but Old Hummie has to be given all the Frequency etc data for a TP before it can see it.

I tried 11106-H-2800 3/4, 12647-V-30000 3/4 and 12736-V- 3333 2/3 with no channels found.

Message was TUNING FAIL.

But given as I posted earlier the obscene angle of the LNB when the dish is so far West, I'm not surprised.

DumbDuck.

[beer4life]

I understand Optus's weird inclination clockwise from the point of view of the observer, I don't understand the WHY, but I know it's there, but I don't understand what you mean by the black lines and their verticality when shown West or East of North.

Wouldn't the skew, from the view point of the observer, seem to be on an imaginary line drawn from the equator North point, bisecting the position of the satellite in the sky?

But given as I posted earlier the obscene angle of the LNB when the dish is so far West, I'm not surprised.
DumbDuck.

Imagine this:
You're at the base of a flagpole, looking up, the pole is parallel to your line of sight.
However as you move further away from the pole, your line of sight to it becomes more obtuse until it finally appears to be at 90 degrees.
The twisting of the dish and hence the Dipole Antenna in the LNB are kept parallel to the antenna on the Satellite. In other words Tx & Rx antennae are kept in the same plane.
That may not be 100% true, as it does not take into account the curvature of the earth, but is near enough for illustrative purposes.
If you still have problems understanding, try with a plain dish to track the Clarke Belt with Azimuth and Elevation adjustment only. Then you'll find that you also have to adjust the Skew in the holder for optimum signal.
I think the way the H - H motors adjust in 3 dimensions is rather ingenious.

Kindest Regards, " The Druid ".

[BlackDuck]

If any one is better at illustrating than I, Please do not hesitate to do so.

Kindest Regards, " The Druid ".
[/COLOR]

I thought I understood skew until the above drawing, I'm asuming that the red lines represent Optus sats and the black lines more conventionally oriented sats.

Ignoring Optus and only taking account of the West most line, How could the polarity possibly be vertical from the point of view of the observer?.
Ignoring the true 3 dimensional planes, and looking only at the 2 dimensional representation, wouldn't the polarity be horizontal instead of vertical as drawn?

And the next CW line, the polarity would be 45 deg, and only on the centre line would the polarity be vertical.

And I agree, when I got my 2nd hand H-H motor I was impressed by the way they used the below centre of rotation crank to correct for rotational skew.

[beer4life]

Ignoring Optus and only taking account of the West most line, How could the polarity possibly be vertical from the point of view of the observer?.

Exactly the point, the observed polarity has changed through 90 degrees as the elevation changes down 90 degrees. (The maths aren't quite that simple). That is why you must adjust the Skew with change in Elevation and Azimuth.
You really don't need to understand, just accept the fact that it is so.

[mtv]

Exactly the point, the observed polarity has changed through 45 degrees as the elevation changes down 90 degrees. (The maths aren't quite that simple). That is why you must adjust the Skew with change in Elevation and Azimuth.
You really don't need to understand, just accept the fact that it is so.

Indeed!

A bigger dish also helps compensate for the skew-compromise required between Optus & other sats.

The options for obtaining perfect skew for both Optus and other sats are:

1. Two separate H-H motors, one with optimised skew for Optus sats and another for the rest (as per B4L)

2. A single fixed dish with multi LNB's each with individual skew adustment for each sat. (eg: toroidal dish)

3. Individual fixed dishes/LNB's adjusted for optimum skew on the sat the dish is pointed at.

4. A single motorised dish (usually polar-mount prime-focus) with a polarotor which remotely adjusts the skew.

In most cases, the compromised skew is sufficient, but if you want/need the very best result possible from each sat, then choose one of the other options.