Problems with LNB Holder/Monoblock

TVDX

A couple of months ago I had some Urlan TV installers out and they tried for a long time to get a monoblock working.
They eventually had to give up and just left it on hotbird.
All ports were set up and the LNB should have worked.
When they twisted it one way, they got Hotbird and the other Astra, but never both at the same time.
I left a single LNB up there and decided that the monoblock didn't work(probably not the case).
My dish is 80cm and it is a strange epilictical shape, a little different to the ones these days, I think, could the strange shape have made the monoblock unuseable or should it work with anything that is 80cm positioned right.
The instruction diagram with Hotbird in the holder and astra loose was observed and still no joy.
Is there some knack to monoblock installation that I am not getting.
The 2 LNB heads in the unit are twistable with 6 settings marked with a line.
What are these about, and also Underneath there are two screws on the LNB that say + and -, what do these do?.
Is there any way I can test if the LNB is working?.


Today I dug it out to try again, went up myself and encountered very difficult screws which were tight as hell.
I presumed taking them out of the holder would work but, in fact it looks like you need to take the third screw out which means the whole LNB holder cap must come off the dish.
The third screw is very long, tightened by a bolt that looks almost stuck on to the arm and not moveable.
Both are very rusted.
What tool do I need to remove this screw and would oiling it up help?.
I can't even try the monoblock without removing it!.
This turned into a long post.
Any help appreciated?.

watty

The monoblock is designed for a particular F/D shape of dish. You can't normally use it with a separate LNB Diseqc swiitch as it has a switch built in (1 is Astra and 2 is Hotbird, so by default it is supposed to point at Astra with no switching sent).

+ - on an LNB usually refers to Polarisation skew, which is adjusted to get best Quality % or bar size.

WD40 (or real cocacola TM) is good for rust.

TVDX

So should the dish be aligned to Astra 1?.
I must also get a picture of the dish and monoblock uploaded

You might be able to identify whether or not the dish which is quite old is the right or wrong shape.

I have some pictures of the dish which I will upload.
I'll also try the coca cola!.
Cheers watty.

Zaphod

The dish shape is non-standard so the monoblock won't see all of the dish surface and may also pick up a share of unwanted background noise.

Normally the dish and centre LNBF is aligned on the weaker satellite, and the second LNBF is placed offset for the stronger satellite.

How does reception of Hotbird compare with Astra with the original LNBF?

TVDX

When last it was checked, the Astra and Hotbird signal individually, when the monoblock was twisted back and forth, were as expected Hotbird 60% strength, 98% quality and Astra slightly more than that.

I think you both might have confirmed what I thought regarding the shape of the dish.
Does it look like a monoblock would not work with it to you?.

TVDX

Would it be possible to remove the dish part leaving the mount and the arm which are both as one!.
And then slot in another dish, perhaps one a bit more modern.

byte

TVDX wrote:

Would it be possible to remove the dish part leaving the mount and the arm which are both as one!.
And then slot in another dish, perhaps one a bit more modern.

Not really no, you'll need to change the whole lot. I'd doubt the reflector of another dish will be the perfect size with the right parabolic properties for the dish you have.

I'd say change the lot.

Zaphod

A longshot but if you have a signal meter, you could try to mark the elevation and azimuth of the dish for Astra and do the same for Hotbird. Then align the dish in an intermediate location between the 2 positions and centre the monoblock on the feed arm. This is a more effective use of a monoblock and dish than the method outlined above, but more difficult to get right.

tapfit2004

Zaphod wrote:

A longshot but if you have a signal meter, you could try to mark the elevation and azimuth of the dish for Astra and do the same for Hotbird. Then align the dish in an intermediate location between the 2 positions and centre the monoblock on the feed arm. This is a more effective use of a monoblock and dish than the method outlined above, but more difficult to get right.

follow on to whan is said above. try and find 16e with a single lnb, this is mid way between astra and hotbird, and mount the monoblock lnb on the centre of the arm and see what happens. channel frequencys on 16e can be found on lyngsat. 11554 V 28800 7/8 seems to be a strong tp. if this dont work get a motor, looking at the pictures you sent in you would probably be able to receive 30w to 42e no problem (as long as there are no trees or buildings in your line of site.)

watty

Monobloc are limited as it is hard to add 28.2 also.
Monobloc only works with a particular F/D & size of dish

I'd always go for separate LNB, unless
1) Only want 19 & 13 ever
2) Recommended Monobloc for the dish

TVDX

I know it might not be possible to tell from the pictures but considering that the dish can get both Hotbird and Astra on the monoblock with a twist but not at the same time, that maybe I should use dual LNB's with two seperate wires?.

TVDX

Also, does it look like I could add a motor to the set up?.

watty

TVDX wrote:

I know it might not be possible to tell from the pictures but considering that the dish can get both Hotbird and Astra on the monoblock with a twist but not at the same time, that maybe I should use dual LNB's with two seperate wires?.

YES

If the dish is at least 80cm it can be usefully motorised.