Non-motoring > Satellite TV mystery Miscellaneous
Thread Author: No FM2R Replies: 25
View Threaded 

New Mon 23 Feb 15 00:03 
 Satellite TV mystery - No FM2R
I have a house on the beach. Given ther'the location there is no cable tv and no chance of a terrestrial tv signal so I have to use satellite. In this case Amazonas 2/3 Fofor a Movistar service.

I cannot get a consistent signal. Sometimes it works with a signal strength of 85% other times nothing.

The dish is on the roof and as the house is 7 floors high it is not obstructed by anything.

I have used 2 different LNBs, 2 cables, 2 set top boxes and nothing changes. I have had three different blokes out here to do it and all achieve the same result.

I only have one satellite dish, but can that be a problem? Nothing to go wrong, surely?

It works more often in the day and virtually never at night. It does not appear to be cloud cover related.

I also have a Direct tv dish which goes only to the girls' bedroom and works perfectly. Pointing at a different satellite.

Any ideas what to try or look at?
Obviously I am in the southern hemisphere, but that shouldn't be material.
Reply to this message | Report message
       
New Mon 23 Feb 15 04:10 
 Satellite TV mystery - sherlock47
do you get some indication of signal quality? as well as signal strength. Is the cable run all 7 storeys? if so have you tried putting receiver closer to the dish?

does the receiver show the signal strength of the transponder/channel that you actually want to receive? Some systems/receivers (Sky boxes for eg ) show a strength indication which has very little to do with what you actually wish to watch.

Are you absolutely sure that the dish is spot on. I have seen problems where the dish is misaligned, reception is is only just working from a sidelobe on the dish - leaving it very susceptable to interference and loss of programs at certain times of day.
Last edited by: sherlock47 on Mon 23 Feb 15 at 04:15
Reply to this message | Report message
       
New Mon 23 Feb 15 08:17 
 Satellite TV mystery - Zero
I would start by experimenting with a shorter cable, having the STB nearer the LNB on the top floor say.

Reply to this message | Report message
       
New Mon 23 Feb 15 09:27 
 Satellite TV mystery - Slidingpillar
Have the installers used a proper signal strength meter? Because if they have, they ought to be able to pass comment on the level of signal received and the dish size.

What is the cable? CT125 is the normal recommendation, but CT100 can work ok. I tend to use CT125 for everything as if you buy a reel, price per metre tumbles.

From what you say though, my 2p would on the dish size being marginal.
Reply to this message | Report message
       
New Mon 23 Feb 15 12:42 
 Satellite TV mystery - No FM2R
I have tried a shorter cable - about 4m.

Signal quality is never very good, even when its working, and it disappears just as signal strength does.

Very interesting thought about dish size. It would be surprising but I shall need to look into it. There is not a wealth of internet knowledge around in Chile - DIY is not usual and typically the people who do this type of thing are not really computer users.

Equally I am still on my Christmas holidays (yes, really) and I dont have a computer here, just a smartphone, which is limiting for research.

I do have a meter. Its not a great one but I've successfully set up several systems before with it.

Tradesmen are an issue here. Frequently not the brightest or conmunicative.
Reply to this message | Report message
       
New Mon 23 Feb 15 12:44 
 Satellite TV mystery - No FM2R
P.S.

How critical is the dish itself, other than just size?

Its not obviously bent or twisted, but could it be affected by a twist thst couldn't be easily seen?
Reply to this message | Report message
       
New Mon 23 Feb 15 12:56 
 Satellite TV mystery - Zero
>> P.S.
>>
>> How critical is the dish itself, other than just size?
>>
>> Its not obviously bent or twisted, but could it be affected by a twist thst
>> couldn't be easily seen?

Its possible, it needs to focus on the LNB obviously. How about wind? is it windy when signal dispaears? could be its lose and moving off beam
Reply to this message | Report message
       
New Mon 23 Feb 15 13:04 
 Satellite TV mystery - No FM2R
I don't think its the wind. Firstly there isn't very much and secondly its pretty rigid.

Also its on the same part of the roof as the DirectTV didh which is untroubled.
Reply to this message | Report message
       
New Mon 23 Feb 15 13:58 
 Satellite TV mystery - Fullchat
Are all connections good and clean? It is recommended that all exterior plugs / connections are smeared with silicon grease to keep out the damp and prevent corrosion. There may also be an internal break in the cable.
Last edited by: Fullchat on Mon 23 Feb 15 at 13:59
Reply to this message | Report message
       
New Mon 23 Feb 15 15:16 
 Satellite TV mystery - No FM2R
All cable and connections are new although I realise that is not the same as good. I have tried two different cables.

It's aimed correctly I think. Measured, re-measured and started from scratch several times.

I'm beginning to think it must be the dish itself although its difficult to see how.
Reply to this message | Report message
       
New Mon 23 Feb 15 16:31 
 Satellite TV mystery - sherlock47
Whilst it should be possible for all dish makers to make a perfect part parabola there can be a surprising difference in signal strength with some of the cheap dishes. Also the shape can reduce the signal (increase noise) if the LNB is not designed for a special shape dish. (Regard it as the the focus is not accurate). Looking at some of the signal charts it would appear that it is not a marginal reception area - altho I do not read spanish, and do not know exactly where you are. You are possibly better off with expensive branded products.

Do you know any close neighbours with similar kit?

PS cheap old analogue meters can be worse than useless.

It is also possible in fringe areas that there can be 'holes' in the coverage - remarkably well defined too. Look at the problems seen in S of France and Northern Spain when Astra footprint was tightened.
Last edited by: sherlock47 on Mon 23 Feb 15 at 16:34
Reply to this message | Report message
       
New Mon 23 Feb 15 16:38 
 Satellite TV mystery - Aretas
I second Sherlock's ideas. These satellites are not entirely stationary and if your dish is not correctly aligned the signal could be moving in and out of your dish window.
Reply to this message | Report message
       
New Mon 23 Feb 15 16:39 
 Satellite TV mystery - No FM2R
Just been for a walk and there is another house with the Movistar service. Its the same size dish as mine and both are branded/painted Movistar.

He has a good strength and quality of service and his dish is much lower than mine.

I am in Renaca which I would expect to have a good service.

Would you expect the bar which joins the LNB to the dish to be straight. I mean, not twisted or angled to one side?

And are all dishes the same design other than size? Are they interchangeable?
Reply to this message | Report message
       
New Mon 23 Feb 15 17:11 
 Satellite TV mystery - sherlock47

Would you expect the bar which joins the LNB to the dish to be straight. I mean, not twisted or angled to one side?

Bar should be straight - but the LNB may not be 'straight' in the mounting bracket this is known as the skew.

If the arm is bent twisted the lnb will not be at the focus of the dish. The distance ( ie how the LNB sits in the collar) , also has an effect in marginal situations.

Height of dish is not normally of any concern provided there are no obstructions. My advice is always install at a position where you can adjust whilst standing on terra firma :)
Reply to this message | Report message
       
New Mon 23 Feb 15 17:34 
 Satellite TV mystery - Zero
IS it a roundish dish or a "side to side" dish?

It is acceptable, depending on the design of fixing the bar to the dish to have the mounting bar bent in a vertical direction (up or down) to achieve the focus sweet spot, but I can't think of any circumstances where its acceptable to have the bar bent in the horizontal (side to side)

There should not be any twist in the bar, the skew is adjusted in the LNB clamp.
Reply to this message | Report message
       
New Mon 23 Feb 15 17:54 
 Satellite TV mystery - Armel Coussine
I'm still amazed after all these years that the things work at all. But they do, even in the utter tangle and electronic bedlam of London. Aerospace communications technology, wow!
Reply to this message | Report message
       
New Mon 23 Feb 15 23:09 
 Satellite TV mystery - No FM2R
>> IS it a roundish dish or a "side to side" dish?

I don't know. it looks just the same as a Sky dish in the UK.
Reply to this message | Report message
       
New Mon 23 Feb 15 23:16 
 Satellite TV mystery - Zero
roundish then - just get a bigger one.
Last edited by: Zero on Mon 23 Feb 15 at 23:16
Reply to this message | Report message
       
New Tue 24 Feb 15 07:25 
 Satellite TV mystery - sherlock47
I do not regard the current Sky dish as round - it is oval and uses a LNB specifically matched to the oval shape. (ok it is roundish, but you get my drift?)

Quote from a reputable site
Sky minidish LNBs are different from standard LNBs.

1. They have a "spigot" or "finger" which slides into the dish arm.
2. They are designed to focus on an oval area. This prevents them from picking up excessive background noise, which an ordinary LNB will do when used with an oval dish.

www.satcure.co.uk/tech/LNBpics.htm for further info


Has an installer in South America been importing (very) cheap Sky dishes and rebranding them?
Reply to this message | Report message
       
New Tue 24 Feb 15 07:34 
 Satellite TV mystery - Zero
>> I do not regard the current Sky dish as round -

neither did I describe it as such, hence the use of the word "roundish"

Reply to this message | Report message
       
New Tue 24 Feb 15 08:22 
 Satellite TV mystery - sherlock47
then, what is side-to-side? I was trying to differentiate between 'circular', and Sky oval!
Last edited by: sherlock47 on Tue 24 Feb 15 at 08:25
Reply to this message | Report message
       
New Tue 24 Feb 15 08:48 
 Satellite TV mystery - Zero
>> then, what is side-to-side? I was trying to differentiate between 'circular', and Sky oval!

www.sadoun.com/Sat/Order/Dishes/Dish-Network-Satellite-Dish.htm

top one
Reply to this message | Report message
       
New Tue 24 Feb 15 08:50 
 Satellite TV mystery - sherlock47
>> >> then, what is side-to-side? I was trying to differentiate between 'circular', and Sky oval!
>>
>> www.sadoun.com/Sat/Order/Dishes/Dish-Network-Satellite-Dish.htm
>>
>> top one
>>

Looks oval to me! Sky like!
Reply to this message | Report message
       
New Tue 24 Feb 15 09:00 
 Satellite TV mystery - Zero
Oh whatever, roundish and side to side explained the types of dish perfectly.
Reply to this message | Report message
       
New Tue 24 Feb 15 09:41 
 Satellite TV mystery - Slidingpillar
Look at this big dish:
www.nt.tuwien.ac.at/fileadmin/topics/RF_engineering/prj_most/gal/02_parabolic_antenna.jpg

The Sky dish and many others is a bit from the lower section as opposed to a full parabola. Quite normal in the domestic market to do this, but means it's very hard to determine how to point one without a meter.

Added, I think the correct term to describe it is an offset dish
Last edited by: Slidingpillar on Tue 24 Feb 15 at 09:44
Reply to this message | Report message
       
New Tue 24 Feb 15 10:44 
 Satellite TV mystery - Fursty Ferret
Temperature changes?

Depending on the cable the copper core can shrink slightly with falling temperature (especially if originally laid in the sun) and retract out of the F-type connector.

Also, the quality of the cable has a huge impact on satellite reception, especially over long runs. Is it semi-air spaced dielectric with copper tape and copper braid (or foam dielectric) or a cheaper variant (silver foil)? Sky don't permit any other cable than the first as the signal loss is exponential with distance.
Last edited by: Fursty Ferret on Tue 24 Feb 15 at 10:47
Reply to this message | Report message
       
Latest Forum Posts