Satelitte TV cable issues?
Discussion
We had cable TV feeding into the bottom of the house, and it worked in all the rooms the system was run to. Now we have changed to satellite TV fed in from the roof, and it doesn't reach any rooms. The 'technicians' are telling us that the splitters used in the system are like a one way valve and only let signal through in one direction, which is BS as I have found a spare one and tested it. It works both ways round.
Unfortunately most of the wiring was buried inside the walls/ceilings when the house was built, so I can't access it to test it stage by stage.
Last night I bought a cable TV signal amplifier, but it actually shuts the signal off rather than amplifies it when put in circuit with the working part of the satellite TV system.
So, is it total BS about 'splitters' being one way, or are some like that? I have no idea exactly which models/types were buried when the co-ax wire was installed.
My personal opinion is that the signal is too weak to get to the other bedrooms, as the wire does take a somewhat tortuous route. I shall go and do battle with the satellite people later today.
We're in the Philippines by the way, so things are done differently here......
Unfortunately most of the wiring was buried inside the walls/ceilings when the house was built, so I can't access it to test it stage by stage.
Last night I bought a cable TV signal amplifier, but it actually shuts the signal off rather than amplifies it when put in circuit with the working part of the satellite TV system.
So, is it total BS about 'splitters' being one way, or are some like that? I have no idea exactly which models/types were buried when the co-ax wire was installed.
My personal opinion is that the signal is too weak to get to the other bedrooms, as the wire does take a somewhat tortuous route. I shall go and do battle with the satellite people later today.
We're in the Philippines by the way, so things are done differently here......
I've seen something mentioned on 'DC pass through' when I was researching splitters. What is it? Just a way of sending power to the dish? And I also wondered where the power comes from for the signal from the dish, So your point is probably the answer. Satellite signal must act differently than normal cable signal.
I also noticed some very light sparking when connecting the co-ax to the wall outlet, on some of the numerous times I reshuffled cables and connections......
I also noticed some very light sparking when connecting the co-ax to the wall outlet, on some of the numerous times I reshuffled cables and connections......
Splitters generally contain a combination of inductors and capacitors.
To DC voltage, these inductors are a short circuit.*
So you need to provide a DC path for the current to flow unhindered to the dish (which is what splitters with DC pass through do).
The sparks you see, are most likely floating AC voltage (quite common and mostly always harmless) from capacitors in switch mode power supplies, connected to earth (your satellite cable is probably at earth potential).
Avoid touching the two parts that spark - you may get a slight tingle (and in bad cases a nasty shock - but one would hope your house has some kind of earth leakage detection on your mains switchboard).
ETA: I should have said that the inductors can often be in parallel with the cable - hence at DC - they are a short circuit.
To DC voltage, these inductors are a short circuit.*
So you need to provide a DC path for the current to flow unhindered to the dish (which is what splitters with DC pass through do).
The sparks you see, are most likely floating AC voltage (quite common and mostly always harmless) from capacitors in switch mode power supplies, connected to earth (your satellite cable is probably at earth potential).
Avoid touching the two parts that spark - you may get a slight tingle (and in bad cases a nasty shock - but one would hope your house has some kind of earth leakage detection on your mains switchboard).
ETA: I should have said that the inductors can often be in parallel with the cable - hence at DC - they are a short circuit.
Edited by TonyRPH on Saturday 27th April 15:46
TonyRPH said:
Avoid touching the two parts that spark - you may get a slight tingle (and in bad cases a nasty shock - but one would hope your house has some kind of earth leakage detection on your mains switchboard).
Er, nope, when the house was wired they neglected to put the earth/ground system in. That is quite normal in these parts of the world. I can see I have some re-routing to do if we want to get this satellite system to work effectively, and it appears the 'technicians' know less than I do about it all.
ETA: I've just been and taken measurement with my trusty multimeter. It reads 18 volts at the coax output.
However, it also shows a dead short if I connect the meter across the house system, like something is shorting the inner and outers together somewhere. Whether some splitters do that for some reason I know not. The one splitter I have laying around does not short the poles.
Very odd, because the cable TV system works throughout the house, but is really poor in one room. I am assuming the short circuit is on the leg to that room. Short of tearing out walls/ceilings I have no way to fix it.
Edited by King Herald on Sunday 28th April 03:05
King Herald said:
<snip>
ETA: I've just been and taken measurement with my trusty multimeter. It reads 18 volts at the coax output.
However, it also shows a dead short if I connect the meter across the house system, like something is shorting the inner and outers together somewhere. Whether some splitters do that for some reason I know not. The one splitter I have laying around does not short the poles.
You're seeing a short circuit, because splitters contain inductors (a kind of coil) in parallel with the signal cable. The inductor measures as a short circuit at DC - but at RF frequencies, it's a nice resonant circuit, usually measuring around 50 to 75 ohms.ETA: I've just been and taken measurement with my trusty multimeter. It reads 18 volts at the coax output.
However, it also shows a dead short if I connect the meter across the house system, like something is shorting the inner and outers together somewhere. Whether some splitters do that for some reason I know not. The one splitter I have laying around does not short the poles.
The special splitters with DC pass through referred to in earlier posts use a different method of splitting the signal, to allow DC voltage to pass unhindered.
You will see the same effect with any aerial - it is a short circuit at DC, but generally measures around 50 to 75 ohms at RF frequencies (the frequency for which the antenna was designed for).
TonyRPH said:
You will see the same effect with any aerial - it is a short circuit at DC, but generally measures around 50 to 75 ohms at RF frequencies (the frequency for which the antenna was designed for).
This was with the aerial/dish disconnected, just the wiring system, with nothing plugged in. Tomorrow I'll call up the company and ask that a real technician comes out, not some installer, which is all the guy was. The shop was closed when I went round there on Saturday...
And what is a 'magic eye'?
King Herald said:
TonyRPH said:
You will see the same effect with any aerial - it is a short circuit at DC, but generally measures around 50 to 75 ohms at RF frequencies (the frequency for which the antenna was designed for).
This was with the aerial/dish disconnected, just the wiring system, with nothing plugged in. Tomorrow I'll call up the company and ask that a real technician comes out, not some installer, which is all the guy was. The shop was closed when I went round there on Saturday...
And what is a 'magic eye'?
A magic eye is an extension for the remote control, I think to enable remote operation from another room (for example, if you view the output of the lounge Sky box in a bedroom).
h0b0 said:
The DC is for magic eye only. Even if you cause it to drop by not using the right amp you should still get the picture.
No, it's not only for the magic eye.The LNB on the satellite dish is powered from the set top box - and hence you need splitters with DC pass through to power the LNB.
Are we talking before or after the box? If before then I used to specify 1 or 2 dedicated CT100 lines per box depending on what they needed. I never distributed in a domestic install. I know you are not local (neither am I) but assuming you are installing Sky then the standard DVR LNB comes with 4 lines. I have not done an install for 10 years though so my info is out of date.
If its after the box then you don't need to power the LNB as that is done by the dedicated lines. The only power you need is for magic eye (for changing channel). If you have simple Y splitters then these can only work in one direction.
If its after the box then you don't need to power the LNB as that is done by the dedicated lines. The only power you need is for magic eye (for changing channel). If you have simple Y splitters then these can only work in one direction.
TonyRPH said:
If that was just the cable - then indeed a short circuit is not a good thing.
Today the 'tech' came back with the new receiver box, HD quality etc, and we again looked into the coax system. He too agrees the short is not correct. I wired our spare splitter into the system, both the right way, and back to front, and showed him this particular version works okay backwards, but I don't think it is the same model as buried.
h0b0 said:
Are we talking before or after the box?
This splitter is before the box, and sends coax off into three separate rooms. We had planned to put a receiver box in each room, but I don't think that is going to happen now. We are now planning the best way to run more coax, as I'm loathe to start popping holes in ceilings to try and find the errant splitter. Or the wire short. In short we are sending satellite signal in through one of the branches, rather than from the intended main supply point.
You cannot do what you are trying, you cannot really split a satellite signal from a dish, it does not work the same way as the cable TV feed. There are ways to do it using a 'multi-switch' but this gets complicated in a domestic set up. You'll need separate feeds from the dish to each satellite receiver you are going to use, in a UK Sky system this will use a quad or octo-LNB on the end of the dish and cables to each room.
The only way you can distribute the signal is by feeding the RF signal from the main receiver into you distributed cabling, then you will have to watch whatever channel the main receiver is on. You'll need to tune each room TV to the sat receivers RF output.
A magic eye is used to remotely change the channel, say if you're in the bedroom, works on UK Sky systems.
The only way you can distribute the signal is by feeding the RF signal from the main receiver into you distributed cabling, then you will have to watch whatever channel the main receiver is on. You'll need to tune each room TV to the sat receivers RF output.
A magic eye is used to remotely change the channel, say if you're in the bedroom, works on UK Sky systems.
Edited by megaphone on Monday 29th April 10:42
Edited by megaphone on Monday 29th April 10:50
h0b0 said:
The DC is for magic eye only. Even if you cause it to drop by not using the right amp you should still get the picture.
The 18V DC, on the dish connection, is there to switch the LNB to horizontal or vertical polarity, if the OP connects a meter he will notice the voltage changes as he switches channels.The magic eye's use 9v DC out from the RF output on the receiver, very common on UK Sky receivers but not so on others.
megaphone said:
You cannot do what you are trying, you cannot really split a satellite signal from a dish, it does not work the same way as the cable TV feed....
Thanks for the info. The satellite company people don't seem to know any more about it than I do. They have told us we can add another 'box if we want, for extra cost, but we have not yet looked into how or where it will connect. The installer guy seems to think it will work through a normal splitter system. Either that or he is not savvy enough to explain it to me or the wife.
I'm back offshore now, so next time I'm home I'll inquire about this proposed extra box and see just what they say.
megaphone said:
h0b0 said:
The DC is for magic eye only. Even if you cause it to drop by not using the right amp you should still get the picture.
The 18V DC, on the dish connection, is there to switch the LNB to horizontal or vertical polarity, if the OP connects a meter he will notice the voltage changes as he switches channels.The magic eye's use 9v DC out from the RF output on the receiver, very common on UK Sky receivers but not so on others.
So, a satellite system in the Philippines is not going to work in exactly the same way as here. Tbh sky have some odd ways of doing things which we are used to here in the uk, but they are odd compared to everywhere else.
So how big is the dish a what channels are you getting from it?
This will help identify if it is a KU band system (like Europe) or a C band system like older / rest of the world systems.
From memory a C band system can be split because it doesn't have much polarity control needed. There does it only needs on receiver the power the LNB (electronics at the end of the arm) the rest of the receivers can just work off the signal being received.
If it is a KU band system then it can be traditionally split, but if the channels you want are all in one group or band it is perfectly possible to do this.
Let us know the channels you want and I can check up to see if it is C or Ku to start with.
V.
So how big is the dish a what channels are you getting from it?
This will help identify if it is a KU band system (like Europe) or a C band system like older / rest of the world systems.
From memory a C band system can be split because it doesn't have much polarity control needed. There does it only needs on receiver the power the LNB (electronics at the end of the arm) the rest of the receivers can just work off the signal being received.
If it is a KU band system then it can be traditionally split, but if the channels you want are all in one group or band it is perfectly possible to do this.
Let us know the channels you want and I can check up to see if it is C or Ku to start with.
V.
Also, they are half right on the splitter thing.
Usually a splitter is marked with an in and two or more outs. Whilst it is perfectly ok to pass a signal from the in to the outs or even outs to the in, passing a signal from one out to another out will loose a lot of signal. This is called port to port isolation and it to stop interference passing form one out to another out.
It could also be that the cable tv company / install fitted Taps and not splitters, which would work a lot like they have described.
V.
Usually a splitter is marked with an in and two or more outs. Whilst it is perfectly ok to pass a signal from the in to the outs or even outs to the in, passing a signal from one out to another out will loose a lot of signal. This is called port to port isolation and it to stop interference passing form one out to another out.
It could also be that the cable tv company / install fitted Taps and not splitters, which would work a lot like they have described.
V.
Our dish is about .75 metres across, or 2 1/2 feet in old money. And we get about 130 channels.
I never tried the 'out' to 'out' on the splitter, just 'out' to 'in' and 'in' to 'out', which worked exactly the same. The tech/installer swore it could not work like that, but it did. So right now we don't really know exactly what is going on, or who knows what.
I never tried the 'out' to 'out' on the splitter, just 'out' to 'in' and 'in' to 'out', which worked exactly the same. The tech/installer swore it could not work like that, but it did. So right now we don't really know exactly what is going on, or who knows what.
Ok, can you give me some channel names for me to search on, or even better the name of the satellite service you are using.
Also with the splitters, if the signal originally came up from the bottom of the house and now you have turned it around and are using a sat dish at the top of the house. Did they run a cable down the side of the house to feed the sat signal in at the bottom, so in effect the signal flowed in the same direction? Or are they now plugging in at the top of the same cable run and feeding down.
If it is the latter, then the splitters will not work as you will be connecting one of the outs, the other screen with been on the other out and the link into the others will be the in. It is the out to out link that will cause you problems.
Does that make sense. It will help if you draw it out, old cable tv system first.
V.
Also with the splitters, if the signal originally came up from the bottom of the house and now you have turned it around and are using a sat dish at the top of the house. Did they run a cable down the side of the house to feed the sat signal in at the bottom, so in effect the signal flowed in the same direction? Or are they now plugging in at the top of the same cable run and feeding down.
If it is the latter, then the splitters will not work as you will be connecting one of the outs, the other screen with been on the other out and the link into the others will be the in. It is the out to out link that will cause you problems.
Does that make sense. It will help if you draw it out, old cable tv system first.
V.
VEX said:
Ok, can you give me some channel names for me to search on, or even better the name of the satellite service you are using.
This is the company, probably never heard of in the UK. http://www.cignal.tv/VEX said:
Also with the splitters, if the signal originally came up from the bottom of the house and now you have turned it around and are using a sat dish at the top of the house. Did they run a cable down the side of the house to feed the sat signal in at the bottom, so in effect the signal flowed in the same direction? Or are they now plugging in at the top of the same cable run and feeding down.
Their 'tech' eventually decided that was what we needed to do, after making several other excuses, but I ran a temporary cable myself down to the original input at the bottom, and it made no difference, no signal came through to the box at the top of the wiring system.
As I mentioned further up the thread, I am sure there is some sort of 'short circuit' across the system, as it reads so on my multimeter. However, it did work on the cable TV system so that confuses me. it may be something in the splitters, or just a stray shielding wire cutting across some joint somewhere.
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