Satellite Dish / LNB?

[dessiedog]

Since last year's change in the UK TV transmissions via satellite, we have survived(?) with the Sky News channel etc during our visits to the Bearn, 64.

We now understand that UK TV reception is possible with a larger dish, 1.3 or better still 1.5m, and are consequently considering buying one in the UK to install on our next visit in June. Any recommendations /advice on the make / model of dish and LNB to buy, or not buy, would be appreciated.

Thanks in advance. Dessiedog

[PaulT]

Think the main advice is 'the bigger the better' though do compare specifications - gain etc.

As for LNB possibly best to go for one with a name as opposed to one on eBay from China.

[PaulT]

Oh, plus if it is going on a car roof rack then there will be an overhang. Also, look on the Internet for French supplied ones - might be easier than being strapped on the roof.

Obviously, if you have a large van then that is different.

[AnOther]

The size of dish you need varies considerably across the country but the majority seem to manage with considerably less than 1.3m.

For instance in 46 I switched from an ancient UK 'tractor saddle' to an 85cm and it works fine in all but the most ferocious of biblical rain and I believe that is fairly typical.

[PaulT]

I'm south of you Ernie and an 85cm dish would not work and the OP is even further south.

[Quillan]

Well the OP said at the beginning that he lived in Bearn which is the Pyrenees so he will need a 1.3M dish.

The rule is the bigger the dish the further away from the area at which the beam is aimed you can go. You should remember that technically the biggest dish you can use with the Astra satellites is 60cm, beyond that they will not support you. That said we know people in Spain with 2.4M dishes that get Sky/FreeSat without problem.

As said go for a good named LNB. Inverto Black Ultra is a good LNB but the Ivacom is much better but three times the price. So what are you paying for when you go 'expensive'. Well it's the signal to noise ration or as you see it on your decoder Signal Quality. Most LNB's claim to have low one (this translates into a higher percentage when looking on your decoder) but this is measured in a laboratory at a set temperature or range of temperatures. Given where you are (like me) you want one that performs over a large spectrum of temperatures (-13 to +40). It needs to perform well in the sand storms we get from the Sahara (when we get the red sand on our cars which we have had quite a bit over the last two weeks and it's starting again today). You also want one that can deal with large dishes without the quality falling off round the edges. This is why down here people will recommend either of the two I have mentioned. If you have a long cable run (20m+) the Invero is a better bet. If you really want to go 'belt and braces' go for a 1.5 with a C120 LNB (preferably Ivacom) and a feed horn. It will give you a picture even in heavy rain and sand storms after those around you have long lost theirs.

[AnOther]

The problem is Paul that it's not that linear and predictable and for a given dish size results can vary hugely over distances of a few 10's of km.

Probably the best way to determine what you need in any given location is to find out what others in your immediate vicinity are using.

[HoneySuckleDreams]

we're just over the border in 65.

you could possibly get away with a 1.25-1.30m but it is variable in the region, there are peaks and troughs. That is to say 1m may work in one place and 20K away you may need a 1.25m dish

I bought a 1.5m (from some company on fleebay in Germany) dish as I thought it would be a bit future proof for a while, especially as they decides to wobble/tighten the beam a bit further. The LNB , I can't remember where I got it from, but to be honest it doesn't make much difference. The dish size is the bit that matters and it's worth the cost of getting a man with a proper device to set it up properly, especially of you decide to buy a bigger dish as it needs a bloke with muscles to get it into position. 

And don't try and fit a 1.5m dish to your chimney as it will rip your house down. They are rather large and it's difficult to not make your house look like Jodrell bank

[AnOther]

Not aimed at your comments Q but there is an awful lot of BS spouted about LNBs, particularly about the noise figure which ironically is of virtually no significance at all !

Putting a system together to work satisfactorily in marginal situations needs a calculated and scientific approach, not just the buying of a humongous dish and the most expensive LNB you can afford.

[url]http://www.satcure.co.uk/tech/lnb.htm[/url]

[Quillan]

[quote user="AnOther"]Not aimed at your comments Q but there is an awful lot of BS spouted about LNBs, particularly about the noise figure which ironically is of virtually no significance at all !

Putting a system together to work satisfactorily in marginal situations needs a calculated and scientific approach, not just the buying of a humongous dish and the most expensive LNB you can afford.

[url]http://www.satcure.co.uk/tech/lnb.htm[/url]
[/quote]

Very true as are the comments in the link you gave. However some of the more expensive LNB's are properly tested unlike the cheap ones. The give a much better performance across the frequency spectrum and can deal with bigger dishes better when they are mounted further away from the dish where you tend to get more 'noise'. The information in the link is mainly about the UK where you get plenty of signal.

All this technical stuff however is beyond most users, they just want a dish that works. It is much easier for instance to explain how these low quality cheap LNB's and dishes physically effect your TV reception.

A poor quality LNB will manifest it's self in several ways. One that cannot give the same quality of signal across all the frequencies will in poor conditions allow you to watch some channels and not others. One that can't give the same signal to noise ratio over the whole of the dish size means that you will notice little difference between say a 90cm dish and a 120cm dish because it can only 'see' 90cm of dish with a good signal to noise ration. One that has poor seperation between virtical and horizontal will also allow some channels to work in certain conditions and not others.

It's the same with dish quality. Some are made with thin aluminium which flexes in the wind and causes pixilation when the wind comes from a particular direction. If it does not 'flex' back the dish becomes distorted and reduces the signal presented to the LNB and with these size dishes 2mm could just a well be metre. The more you pay the thicker the material, the less the effect and the better ability to return, when flexed, to it's original shape. Indeed a resin dish is much better than a metal one when you talk big sizes as it is far more rigid. Likewise cheaper metal dishes are made in a press and are not always that accurate and the last 10cm on a 120/130cm dish may not even focus correctly on the LNB so it will really be as good as a good quality 90cm dish. A good practical example of this is two people I know who live side by side. One has a 130cm dish they paid £120 for and the other paid just under £200. The signal quality is much better on the more expensive dish across all frequencies that the cheap on. It also shows a higher 'power level'. They both have the same LNB fitted.

In marginal areas like down here a separate fed horn can help with signal quality. Given that your dish is not actually round because it is 'off set' the LNB does see the dish as a circle. The issue of a big dish with a normal LNB is that the LNB sees the signal at the top and bottom quite differently and because the outer set of 'rings' (wave guides) can't pull in the signal so well. The same LNB on a 40, 60 or 90cm dish won't have the same problem. The bigger the dish the more noticeable this is.

As you know I spent a lot of time on this last year with the help of a local company playing with several LNB's and dishes of various quality and sizes. We found that a mid range quality dish (Gibertini) performed better that say a Triax which are quite popular, mainly because they are cheap. The best dish by far was the Andrews resin dish but I can't justify the cost.

[PaulT]

To the OP what Ernie says about variation, yes there is. However, if you arrive with an 80cm and it does not work then what do you do. Where I am in 31 had an 80cm dish which was fine until they introduced the UK spot beam. Replaced with a 1.3m and it seems less tolerant of rain than before. Plus, reception varies at certain times of the year. Also, aligning a dish to the spotbeam is also a lot harder.

[Quillan]

[quote user="PaulT"]To the OP what Ernie says about variation, yes there is. However, if you arrive with an 80cm and it does not work then what do you do. Where I am in 31 had an 80cm dish which was fine until they introduced the UK spot beam. Replaced with a 1.3m and it seems less tolerant of rain than before. Plus, reception varies at certain times of the year. Also, aligning a dish to the spotbeam is also a lot harder.[/quote]

You should, in theory be better off than us. It really has to rain hard here to lose the picture, I mean like 'stair rods'.What make/model LNB are you using?

[HoneySuckleDreams]

that was quite an interesting read Q - I know there is a lot of technical stuff around the LNB and the dish size/shape, but the man in the street (me !) really doesn't have anyone to trust when it comes to getting it spot on or the time to play around. There is also cable quality and length to consider, and the box that decodes it all.

For the record we have an Invacom Quad LNB and 1.5m Gibertini Aluminium dish. For the most part we have 90-100% strength and quality all the time although we did lose some signal when it was snowing heavily.  It works for now but I won't be surprised if they tighten the beam even further soon so no matter how big the dish we have we will lose the signal.

[Quillan]

There has been a lot of BS about changing the beam size/shape to take place after Astra 2G was launched. Seeing as it has been launched a while back but has been temporarily used to replace a failed satellite somewhere else they did the final 'tweaking' without it so the changes (if indeed there were any) have been made and there will be no more changes/adjustment/tweaking.

[dessiedog]

Thanks for everyone's prompt responses. I have something to work on now re dish / LNB makes etc., but as we don't live there full time, only visiting 3 - 4 times per year, cost has to be born in mind. It's difficult to justify spending a fortune just to watch UK TV?

Delivery shouldn't be a problem as we have friends who are returning with their van at the beginning of next month, I'll have to check prices etc asap.

Thanks again for your replies - Dessidog

[Quillan]

I would check prices in France as well, you might be supprised

[PaulT]

In answer to:

PaulT wrote:

To the OP what Ernie says about variation, yes there is. However, if you arrive with an 80cm and it does not work then what do you do. Where I am in 31 had an 80cm dish which was fine until they introduced the UK spot beam. Replaced with a 1.3m and it seems less tolerant of rain than before. Plus, reception varies at certain times of the year. Also, aligning a dish to the spotbeam is also a lot harder.

You should, in theory be better off than us. It really has to rain hard here to lose the picture, I mean like 'stair rods'.What make/model LNB are you using?

Positive it is the Inverto Black octo LNB. Channels on the wide beam are no problem (unless the rain is as it was for Noah) just the spot beam. There could be slight interference from a tree about 14m away. However, in good weather signal strength and quality is high.

Someone I know bought a new larger dish and was having big problems with reception. Turned out the dish was distorted.

The other thing with a large dish is that it has more wing force acting on it. When I had aligned mine I drilled through the support and used a nut and bolt to hold it in position. The diameter of the thread of the bolt is slightly less than the hole size and did move very slightly in a high wind but did mean that it only needed a slight tweak to get reception back. I will replace it with a shouldered bolt to fix it more firmly in place.

[Quillan]

The Inverto is a good LNB especially when you have long cable runs, much better than the Invacom. However on shorter runs it is the other way round. I suspect however that as an Octo the switch unit is quite close, within a few metres, no more than five?

I guess it depends where the dish is mounted. Mine is against a wall which protects it most of the time. It is gusting at the moment and there is no movement.

I know for sure, having seen it done, that some feel they can align a dish quite well but come the man with his sophisticated box of tricks and one starts to see that although almost there and appears to give good reception in fair weather there is still quite a bit of adjustment which pulls the signal in more and even more important the quality. Each little tweak improves the quality by half a db and when added up can make quite a difference. I have also seen on cheaper dishes that the LNB does not 'centre' correctly which can be seen if you attempt to tilt (with gentle force) the LNB up or down. There is also a bit to be gained by moving the LNB back and forth. Basically the bigger the dish the more accurate you have to set up the LNB to the dish and the dish to the satellites.

Personally I would pay the money and get a professional to align the dish. You might be pleasantly surprised with the improvement.

[DNALLEY]

I am in 34 200 mts from the beach and have a 90cm dish and freesat box,It took a lot of time setting up and adjusting.I get all channels except when the rain is heavy.