Multi LNB or Motorised

[Newbie1001]

I have done a lot of reading and am almost ready to buy my first system for FTA in UK. I need help on buying LNB's and cabling to suit a twin receiver PVR with diSceq 1.2.

There are 5 separate clusters of satellites I wish to receive and I got the azimuths for my location:

Astra Group 1 - azimuths 156.16 thru 158.3 degrees
Astra Group 2 and Eurobird 1 - azimuths 145.26 thru 146.69
Astra Group 1/3 - azimuths 150.8 thru 151.46
Hotbird 5 - azimuth 147.90
Hotbird 1/7 - azimuths 162.65 thru 163.50

The questions blocking my mind are:-

1. Does one fixed LNB cover all the the signals within one group (say 156 thru 158)? Or does the LNB need to be moved say for the 156.16 and then for the 158.2 (Astra 1 group)? In other words what is the arc bandwidth of a fixed LNB in 80 cms dish in degrees? +/- 1 degree, +/- 3 degrees, or +/- nothing?

2. To get all the above satellites how many LNB do I need?

3. I have a preference NOT to go motorised for reasons of simplicity, icing up, etc. Can it be done with multiple fixed LNB or must I go motorised.

4. In order to get two signals into a twin receiver what type of LNB array do I need to buy for all these satellites?

5. Must I run two feeder cables from the LNB(s) to the receiver inputs, or can it all be multiplexed down a single cable. (approximate length 35 meters). If a multiplex option is possible what should I buy?

Newbie1001

[BGonaSTICK]

Hello Newbie1001

Some very good questions. You have clearly done a lot of good background research.

OK, let me skirt around the specific satellites for a minute, mainly because you have calculated the azimuth settings for your location, so they mean nothing to me

Let's cover the other stuff first, and then get back to which sats you want.

Right, I understand what you mean by Astra1 and Astra2. That's 19.2E and 28.2E. Taking 'Astra1' as an example, you need only one LNB to cover the whole group. They are what is known as 'co-located' and one LNB will do the lot. You just set it up to target the center of the group, and accept the best average result you can get.

The individual satellites within a group tend to move around a little over time, but are clustered around the mid point, so there is no real advantage in trying to hit them more precisely unless you have a very good reason.

You will need one LNB for each distinct orbital location, as defined on Lyngsat.com.

'Multiple-LNBs' is a very elegant solution if you only want a small number of satellites within a fairly tight spread and you clearly know what you want, so that's half the battle

To use a twin-tuner setup with a multi-LNB array you just have to buy twin LNBs instead of single LNBs.
Take the first output from each LNB and feed it into one tuner via a 4-way DiSEqC switch, and do likewise with the second output from each LNB into another 4-way DiSEqC switch and on into the second tuner. That way each tuner stays entirely independent and retains full function.

In general, it is possible to run everything down one cable but when using DiSEqC control and twin tuners, it would all go horribly wrong as they would fight each other for control. Run two cables for sure.

Now, to tidy up.

Note that above, I said 4-way DiSEqC switches. Going for more than four LNBs can be done, but gets a bit messy, and more expensive. Limit yourself to 4 LNBs if at all possible. With a twin-tuner setup, you do have the option to split the LNBs between tuners though. Just have four on one and one on the other, but that would limit your viewing and recording options. As I said, I'd go for four twins if you can.

Now, back to the satellites you want.

OK - Astra1 at 19.2E, Astra2 at 28.2E. All of the Hotbirds are at 13E when they're not being shunted around the arc and renamed! One or two of those babies have been in transit to other orbital locations of late, but they are normally all located at approximately 13E.

Now, I think the other location you're after is probably Astra 1D/3A at 23.5°E. That's OK, but there's not much up there. Check Lyngsat for details. 16E might be a better choice, but of course I don't know what it is you're after.

Hope this helps, and please post back with any more questions.

I hope I've explained that alright.

[Jimdefruit]

Good answer Stick.

I think that for a twin tuner system I would stay away from motorised because that would mean having two motorised dishes to get different satellites simultaneously.

[Newbie1001]

Thanks for the information you gave regarding my puzzle.

I was planning to purchase Tecnisat Digicorder S2 PVR. I used your advice to study LNB choices and come back with another question because there seems so many different kinds....

For the LNB there seems basic options.
4 off twin LNB
2 off Monoblock (Inverto Plus has 6 degree spacing)
2 off Monoblock Diseq (I think this has only one output connection and does not work with Disq switch)
2 off Maximum Monoblock Twin (has 2 outputs)

This is the page where I saw these options:-
http://www.brymar.co.uk/acatalog/Sat..._LNB_s_27.html

[BGonaSTICK]

Yep, there's one there that I've never seen before actually, the Maximum monobloc twin. That's a pretty neat idea, but very expensive!

To go through your listed options:

4 x twin LNB - This is what I would go for. Add two 4-way DiSEqC switches and you have maximum flexibility.

The Inverto Plus monobloc and the monoblock DiSEqC are the same - they only have one output and both of them incorporate a 2-way DiSEqC switch. Both of them will have a fixed offset of 6 degrees, and are therefore only suitable for Astra1/Hotbird combination, or any other 6-degree spaced sats. Nice if you just want those two satellites as they are easier to set up, but not much good for anything else. No good for your twin tuner if you want both to be able to get either Astra1 or Hotbird on either tuner.

The Maximum monobloc twin would take care of Astra1 and Hotbird on both tuners, but you would not be able to then switch to other LNBs as the inbuilt DiSEqC switch is encased in the housing, and is only 2-way in any case.

You only really have one choice if you want to be free from unnecessary restrictions.

HTH

STICK

[Newbie1001]

I learned a lot there on what LNB, cabling and switching to buy. I'll now study the dishes and LNB mounting brackets.

Thanks