Will a better LNB help ?

[hamurabi]

Hello,
I signed up here to see if I can get some advices on LNBs. To say the truth I'm not that versed on the subject of LNB that much. So, I am visiting my uncle who lives in Sierra Leone, West Africa and it seems that Nilesat is the most prominent satellite in most homes. To get a sense of the nilesat coverage, here is its footprint:
58728

As you can see from the footprint, Sierra Leone (tiny country on the west) has no business getting any signal as it is not within the coverage area. But people here have been receiving it since its inception. The signal is good in a clear day and bad when cloudy. Obviously there are some transponders with high signal while others are weak and hence they scramble.

I have made an estimate that around 80% of the channels are received here that run the gamut from perfect to scrambling. Currently my uncle is using an 8ft dish (2.43m). However he is using a cheap LNB which is rampant here. The LNB's catalog seems non-descriptive. The only information one can glean from it is its noise rejection of 0.3dB.

Hence the question, will a new better LNB improve the signal quality of the weak signals that can be perceptible and if so what LNB can someone suggest. Nilesat works in the KU Band. I have been reading that inverto black ultra is a good LNB. Will that cause any improvement. Please suggest any LNB, money is not of the issue. I am obviously aware of the constraints that Sierra Leone is not within the coverage area but 50% + of the channels are playing perfectly here.

[cosworth4x4]

first thing there are 5 foot prints for 7 west , 1 listed is easily visable in sierra leone it has 56 active Ku-band transponders.

is he getting more than that ?

a lot of people recommend the black ultra (not me) but what works well on one dish will not on another im just going by what i tested, and i think you will find it hard to get people to recommend a lnb for youre dish as not many people on here with a dish that size, i think its going to be trial and error on youre part unless someone local in that area can give you better advise.

[cosworth4x4]

dish that size i assume a prime focus, and has its own feedhorn c120 fitting? no c band ?

[hamurabi]

first thing there are 5 foot prints for 7 west , 1 listed is easily visable in sierra leone it has 56 active Ku-band transponders.

is he getting more than that ?

a lot of people recommend the black ultra (not me) but what works well on one dish will not on another im just going by what i tested, and i think you will find it hard to get people to recommend a lnb for youre dish as not many people on here with a dish that size, i think its going to be trial and error on youre part unless someone local in that area can give you better advise.

First of all, thanks for the reply. 56 active transponders seem to be about right of the total that can be received. Can you explain how you managed to know the number of active transponders that can be received here ?

You mentioned that a LNB is specific to dish size. Here, as far as I can tell 2m + dishes are everywhere and Nigerian LNBs are the once used. In fact the LNB used is called 'Eurovisions : extra high gain LNBF'. I google its name but got no match.

I have met with a satellite dish installer here and they seem just to be ordinary laymen who have taken the job just by trial and error. They have no idea about communication technologies so its a waste of time talking to them about gains and losses. The only information I obtained from them was that its impossible to get anything with a smaller sized dish. Hence 8ft and above are the ones used although I am yet to see anything above 8ft anywhere. A 10ft dish needs a lot of space and a strong basement too !!

Here is a look of the the type of dish used :

58729

So what do you suggest I do ?

[cosworth4x4]

First of all, thanks for the reply. 56 active transponders seem to be about right of the total that can be received. Can you explain how you managed to know the number of active transponders that can be received here ?

i just checked the footprint for the area.

You mentioned that a LNB is specific to dish size. Here, as far as I can tell 2m + dishes are everywhere and Nigerian LNBs are the once used. In fact the LNB used is called 'Eurovisions : extra high gain LNBF'. I google its name but got no match.

I have met with a satellite dish installer here and they seem just to be ordinary laymen who have taken the job just by trial and error. They have no idea about communication technologies so its a waste of time talking to them about gains and losses. The only information I obtained from them was that its impossible to get anything with a smaller sized dish. Hence 8ft and above are the ones used although I am yet to see anything above 8ft anywhere. A 10ft dish needs a lot of space and a strong basement too !!

Here is a look of the the type of dish used :

58729

So what do you suggest I do ?


i think its going to be trial and error on youre part as well , pic looks like a c band lnb or is it just a library picture .
what type lnb do you need you say lnbf ? does the mounting take that or been modified to accept it , do you have the feedhorn that will accept a c120 lnb?

[hamurabi]

These pics show the type of dish we use though they are taken from google.
58732
58733
58734

what type lnb do you need you say lnbf ? does the mounting take that or been modified to accept it , do you have the feedhorn that will accept a c120 lnb?

Actually I have what the above means.

[satwyn]

These pics show the type of dish we use though they are taken from google.
58732
58733
58734


Actually I have what the above means.the dish shown looks like a cheap petalised type you would see a vast improvement with a quality dish prime focus or even the andrews 2.4m offset dish

[grafter]

The dish was sold in the UK under the name Fortec Star but Internationally they are also known as Jonsa. They are notoriously bad at Ku, the thin cheap aluminium petals distort very easily and it's quite tricky to get them built and installed without degrading performance.

Before you start thinking about sourcing an LNB it might be worth looking at your installation and checking the dish geometry. Simply look at each petal and make sure it's perfectly aligned to the adjacent one, then, get some thin string, I actually use cotton thread and tape 5 or 6, even more lengths across the face of the dish at various points around the edge. You are aiming to get every bit of thread JUST touching each other in the centre, any gaps or if one thread is pushing those below it means the dish is warped, at least with the Jonsa it's an easy enough job to bend them back into shape! You have to do this when it's installed as it will probably distort if you try to move it after 'stringing' it on the ground. If you gain an extra dB or two it'll make more difference than a simple LNB swap.

If you do want to then try another LNB and you're sourcing from the UK or elsewhere it might be worth buying the Invacom universal feedhorn at the same time. The Jonsa has a f/D ratio of 0.38 so the Invacom is ideally suited to it, I would recommend you try an Inverto Black Pro C120 LNB but only because I've had good results with mine (on a different dish). Google 'invacom_feedhorn.htm#invacom' should produce some results.

[satwyn]

The dish was sold in the UK under the name Fortec Star but Internationally they are also known as Jonsa. They are notoriously bad at Ku, the thin cheap aluminium petals distort very easily and it's quite tricky to get them built and installed without degrading performance.

Before you start thinking about sourcing an LNB it might be worth looking at your installation and checking the dish geometry. Simply look at each petal and make sure it's perfectly aligned to the adjacent one, then, get some thin string, I actually use cotton thread and tape 5 or 6, even more lengths across the face of the dish at various points around the edge. You are aiming to get every bit of thread JUST touching each other in the centre, any gaps or if one thread is pushing those below it means the dish is warped, at least with the Jonsa it's an easy enough job to bend them back into shape! You have to do this when it's installed as it will probably distort if you try to move it after 'stringing' it on the ground. If you gain an extra dB or two it'll make more difference than a simple LNB swap.

If you do want to then try another LNB and you're sourcing from the UK or elsewhere it might be worth buying the Invacom universal feedhorn at the same time. The Jonsa has a f/D ratio of 0.38 so the Invacom is ideally suited to it, I would recommend you try an Inverto Black Pro C120 LNB but only because I've had good results with mine (on a different dish). Google 'invacom_feedhorn.htm#invacom' should produce some results.thought them fortec dishes were made of steel not that it makes any difference in gain i would have thought even a 1.8m quality dish would outperform the fortec 2.4m but as for the lnb trying different models may slightly improve signal strength or even a receiver with a better tuner could work

[grafter]

You're right they are steel, so used to writing aluminium for some other topics I've been working on it just came out LOL

[Rizwan]

From pictures, its look like Prime focus Dish with Prime focus LNB, In my opinion, you can't get much from Inverto Black ultra, but , may be from Inverto Black pro

[stars]

For me it looks like a quite good installation. A KU band LNB with a feed horn for a prime focus dish. If you put a LNBF
you will lose signal strength. If you change the LNB I recommend you to use a C120 LNB for KU Band and a adjustable
feed horn so you can get the right F/D ratio. Invacom ADF-120 is the one to use. But the biggest improvement is the
dish installation and here are many things to think about.

The focal point of this type of 2.4 dish is 91.5 cm from the bottom of the dish.

I have self made a guide regarding converting a 6-feet C Band "Fortec star" typ of dish for KU-Band use but I'm from
Sweden and the guide is in Swedish. But here is a translation of that page via google translate. The page is on my own site.
http://translate.google.se/translate?sl=sv&tl=en&js=n&prev=_t&hl=sv&ie=UTF-8&eotf=1&u=http%3A%2F%2Fwww.the-lighthouse.se%2Feng%2Fsatellit%2F c180%2Fc180.html

Hope it helps

stars :)

[grafter]

Thanks for posting this Stars and for taking the time to do***ent your findings. So much bad press about the Jonsa/Fortec Star that it's good to see some real figures about it. Any plans to do the same with a 2.4m/8ft version? If you know of anything similar done for C band I'd be interested to read it too.

[ouagadougou]

A better LNB or Feedhorn will help but you will need to experiment a bit with LNB's and Feedhorns to get the right match unless someone has already found the best combination for that type of dish.

When I was in West Africa we still had problems when it rained heavily even with the West Africa Spot Beams on some satellites so you will struggle to combat rain fade completely unless you have a large enough dish.

Cheers.

[stars]

Hi grafter.
At the moment I don't have any plans for assembling a 8ft dish, but the procedure
is the same for all other dish sizes. Only the f/d ratio and the focal point are different.

Well the pole mount that I have made will not fit other dishes but the blueprints are there
so they can be a good start for a design of your own. The pole mount that comes with
the dish isn't that good if you want to get weak signals its very hard to fine trim.

I have also read a lot of bad press about this type of dish and most of the bad press
are based on poor knowledge about the differences between C, KU Band and
Offset vs Prime Focus dishes. So I made this guide so other people could get a better
knowledge about this area and maybe waste a little less time and money on something
they didn't know so much about.


If you know of anything similar done for C band I'd be interested to read it too.
The assembly procedure is the same for C-band and KU-band only that the tolerances are bigger
for C-band due to the lower frequency. That is why a mesh dish works for C-band but NOT
for KU-band, if you want to get weak signals. Well you also need a LNB and a Feed horn for C-band use.

cheers stars :)

[grafter]

IMO most of the bad press over here was due to it being sold by a high st electronic company to people who just wanted to watch football without paying for it. They got set up with no or very little thought about fine tuning and failed to produce the results, plus the fact they are very thin and flimsy in design :smilielol5: There was a thread on another board some years ago from a commercial (broadcast industry) installer who spent some time setting one up and he acheived very good results with it but said it would hard to maintain in bad weather due to the poor design.

I've been toying with the idea of getting a 2.4 version, I've enough patience and I'd like to think practical experience of setting up dishes to maximise its performance on Ku even though my primary goal would be to use it on C band. I've got a 1.8m Precision/Elite at the moment which performs very well and probably has better efficiency than the Jonsa, bearing in mind I'd have to make a polar mount and probably strengthen it I may end up spending quite a bit of money and time only to gain a dB so am waiting to spot one at the right price.

[satwyn]

IMO most of the bad press over here was due to it being sold by a high st electronic company to people who just wanted to watch football without paying for it. They got set up with no or very little thought about fine tuning and failed to produce the results, plus the fact they are very thin and flimsy in design :smilielol5: There was a thread on another board some years ago from a commercial (broadcast industry) installer who spent some time setting one up and he acheived very good results with it but said it would hard to maintain in bad weather due to the poor design.

I've been toying with the idea of getting a 2.4 version, I've enough patience and I'd like to think practical experience of setting up dishes to maximise its performance on Ku even though my primary goal would be to use it on C band. I've got a 1.8m Precision/Elite at the moment which performs very well and probably has better efficiency than the Jonsa, bearing in mind I'd have to make a polar mount and probably strengthen it I may end up spending quite a bit of money and time only to gain a dB so am waiting to spot one at the right price.do you have a polar mount for the precision dish i had to modify an irte polar mount to fit mine

[grafter]

I do, the dish was bought second hand so I don't know if it's an original Precision model but it certainly looks like it.

58779

[satwyn]

don't think the polar mount is original i've had a few in the past and they were more robust with a full circle ring that bolted to the back ring on the back of the dish and galvanised but who knows they could have sold different types of polar mounts should have kept 1 but the irte mount is quite solid so it does the job

[grafter]

Could be an early one, when I spoke to someone at the company about a new feed for Ku they said it was an old serial number. Anything bigger than what it is would be overkill anyway, this is on the clifftop overlooking the Channel and has taken a few 90mph gusts and sustained 70mph winds without any movement.

[satwyn]

Could be an early one, when I spoke to someone at the company about a new feed for Ku they said it was an old serial number. Anything bigger than what it is would be overkill anyway, this is on the clifftop overlooking the Channel and has taken a few 90mph gusts and sustained 70mph winds without any movement.yes could be i have had 3 of the 1.8m precisions in the past the first was an early one with 4 feed arms and the dish was deeper than the ones produced later still have the feed holder for the 4 arm version

[holmroad]

yes could be i have had 3 of the 1.8m precisions in the past the first was an early one with 4 feed arms and the dish was deeper than the ones produced later still have the feed holder for the 4 arm version

Cheers mate, so which in YOUR opinion have you found is the BEST one of all - if its truly as simple as that? lol!!:respect-051:

[satwyn]

i was told the early ones were better for c band but who knows never looked into it what i need to do next is see if i can lock onto jsc on 7w with the precision 1.8m