Cables for sat dish

[AlexCarp]

I am doing some renovations. While I am at it I want to install cat5e cables on the roof in case in the future a satellite dish is ever needed. Installing cables after will mean running on the outside of the house. I was told cat5e will be fine and two cables will be needed. Is this so? Comments welcome.

 

[Lucid]

I haven't come across anyone doing baluns for the feed direct off the LNB. I'm not saying that it isn't possible. It's just that it's not practical.

For a start, satellite coax (WF100/WF125/WF165 etc) is cheap, so there's no cost advantage running Cat cable + baluns. Second, it'll run long enough distances for domestic use; so there's no distance advantage with Cat in a domestic setting. Third, the coax cable is designed for outdoor use. If Cat was an option then you'd need outdoor rated cable (more expense) and a weather-proofed balun. These aren't the only issues. But by now most of us would look at the Cat alternative as impractical.

Baluns and Cat typically solve problems of cost or distance. Neither of these is really an issue with coax. If you want to future-proof to some degree, then put in conduit to make it easy to pull new cable. This way, if there ever comes a time when we stop using gigahertz rated coax for the signals off an LNB (or stop using LNBs!) then at least you can make changing over easy.

 

[AlexCarp]

Thanks for the quick response. I have satellite cable, so if I run that up to the chimney pot with cables terminated in a weatherproof box it will be ready? Do the dishes need two cables?

 

[Lucid]

How many cables you need depends largely on how many- and what type- of satellite receivers you want to run. For example, a recording Sky box or a twin tuner Satellite recorder needs two feeds off the LNB. If you have a second recorder box elsewhere then that too will need 2 feeds. Satellite tuners (no recording or only "record what you watch") will take a single feed. If your TV has a Freesat tuner then this will usually be a single connection.

Most people's experience of satellite is either via the Sky service or Freesat. These aren't the only services, but let's deal with them in isolation for the moment. The signals for both services come from the same satellite. So a dish aligned for receiving Sky with work for receiving Freesat of the tuner/recorder boxes are swapped.

The dishes erected for Sky/Freesat use will typically have an LNB with 4 outputs. This will feed either 2 recorders (2 cables each) or 4 tuner boxes (single cable each) or 1 recorder + 2 tuner boxes.

4 output LNBs aren't the only type available though. There's an 8-way version too.

Installs that are more complex will use something called a Quattro LNB (still 4 outputs) and then feed that signal in to a device called a multi-switch. You'd find this sort of arrangement in very large houses, and in hotels, and in blocks of flats.

I mentioned earlier that Sky/Freesat aren't the only satellite services available. The sky is packed with satellites, all of them at different geo-stationary orbits and beaming their signals down to earth. The UK receives signals from lots of foreign language satellites. To pick up those signals often requires a different dish and LNB and for that to be pointing at a different part of the sky. So, what cables you need does depend on what you want to receive and then how you want to deal with the signal.

What is it that you want to do.... recieve Sky/Freeview or something else instead/as well. Then how many rooms do you want to feed that signal to?


P.S. If you find the answers here useful, please use the Thanks button at the top right of the specific post. It costs you nothing and it helps others when they're searching for answers. Thanks

 

[Sam Gangee]

Note: typical life of coaxial cable outdoors is 5 years before signal loss becomes measurable*. For unprotected cable, ten years is about the limit. If you protect it with paint or run it inside conduit it can last for decades. Bear this in mind if you install cable for "futureproofing".

* UV in sunlight eventually causes the plastic sheath to degrade, making it porous and allowing moisture ingress. Obviously the life of the cable is very dependent on its UV resistance, the amount of sunlight and the amount of rain and wind (which has an abrasive action).

 

[AlexCarp]

Thanks for the responses. I find some of it confusing with acronyms, etc. I just want to know how many satellite cables I need to run up to the chimney pot. The cable is being run up the inside of the disused chimney flue to the pot on the roof. The sat cable can always be wrapped with PVC tape to extend its life outdoors. Only a small amount of cable will be outdoors at the chimney pot. Sorry to be so dumb in this. I always though the cable runs from the dish to a box and then to the tv's. I thought any extra tv' would have extra cable from the box leaving the feed from the sat dish untouched.

Lucid you state 4 outputs. Is this 4 cables from the dish into the house?

 

[plugwash]

Assuming a "sky-like" system there are basically three options.

Option 1: a single decoder box feeding all TVs. This means that you can only watch one sattelite channel at a time in the whole household. Also newer sky boxes apparently need an add-on module to support this setup. If the box is a single tuner one then it will need a single connection to the dish, if it's a twin tuner box it will need two connections to the dish.

Option 2: multiple decoder boxes fed straight from the dish. In this case you need one or two (depending on the type of box) cables from the dish to each box. If you want sky on the extra boxes you will need a multiroom subscription. You are also limited to a maximum of eight tuners total this way.

Option 3: multiple decoder boxes with a multiswitch, in this case you run four cables from the dish to the multiswitch and then feed the decoder boxes from the multiswitch as above. You can support massive numbers of boxes off one dish this way but the multiswitches and associated gear can get a bit expesnive.

 

[AlexCarp]

Plugwash, thanks. Ok to future proof it is best to run 4 cables to the satellite dish location, to cover all bases?

The dish cables will be run to a central location where a patch panel will be. From the panel two cat5e cables and 2 sat cables will be run to each room. I want to know the maximum number cable to run to the chimney pot. The dish may be fitted in 1, 2, 10, 15 years time. and what system is not known. Thanks again.

 

[Sam Gangee]

Four cables would do because if you needed more than 4 feeds you could fit a QUATTRO LNB to the dish and connect it to a multiswitch with as many outputs as you want. A multiswitch will also carry the aerial feed (if you wish).

Note, however, that the minimimum dish size for a multiswitch would be 60cm and I'd be very wary about mounting any dish on a chimney without an engineer's inspection - and some areas require planning permission.

Frankly, there are too many "IFs" and you should really decide exactly what system(s) you plan to install before committing it to cable. You might decide, for example, that a "Loft Box" system would suit your requirements better. I strongly recommend you do your homework before making any decision:-

http://www.satcure.co.uk/tech/lofthelp.htm
http://www.satcure.co.uk/tech/multiswitches.htm

 

[AlexCarp]

Sam thanks. Unfortunately I cannot plan for years to come, as I will not know the requirements then. Less or more cables may be needed by future systems. No one knows. I want to future-proof and apply some common sense to it.

 

[Sam Gangee]

Technology moves too quickly to allow for future planning so decide what you want now and leave the future to look after itself. The British government has already stated its intention to phase out Freeview in favour of Internet delivery. It wants to sell off ALL the bandwidth for mobile phone use. Satellite TV might go the same way.