How can I get Freeview distribution to 15 rooms?

[Jagjock]

I have just started managing a large house with 15 separate residents in their own rooms. I need to supply freeview to all rooms What is the best system and what equipment do I need to achieve this? Can it be done with a single roof top antenna? If so how do I split the signal without loss of quality? Do I need a special antenna as the signal is being distributed to so many rooms? Any help much appreciated.

[ianh64]

Are you planning on giving them their own STB or a centralised system where they get a selected choice of channels?

[Singh400]

Wow, sounds like an interesting project. I'd guess the easiest way would be to have a central server of some sort.

But I'm not really sure. If you do manage to get it done, let us know how!

[MartinImber]

Quite easy get your distributed system good enough to handle the digital signals and a box for each room - are the residents permanent?

[SamRadford]

It all depends on the lengths of cable required to reach the furthest points.

Ideally it needs a launch amp with appropriate taps if the cable runs will be lengthy.

If you can use a "star" arrangement with no cable run exceeding 50 metres then the taps can be dispensed with, but you'll use more cable and you'll still need amplifiers and attenuators.

This is actually not such a simple job as you might think!

[Jagjock]

Thanks for those replies. This is my first attempt to get advice on AVF as I have failed everywhere else I've tried . I intend each room to have its own freeview box so they can choose channels. If I mount the antenna on the chimney (The highest point) the longest cable run will be 20 metres approx. Is it easier with some kind of distribution box in the loft . What are such boxes called and where do I go online to see some specs?

[bigtim]

Originally Posted by Jagjock

Thanks for those replies. This is my first attempt to get advice on AVF as I have failed everywhere else I've tried . I intend each room to have its own freeview box so they can choose channels. If I mount the antenna on the chimney (The highest point) the longest cable run will be 20 metres approx. Is it easier with some kind of distribution box in the loft . What are such boxes called and where do I go online to see some specs?

They're called distribution amps.

Here's one at maplin (obviously only 8 way):

http://www.maplin.co.uk/Module.aspx?...%20amp&doy=9m2

Could poss use 2 of these to do the job (one ouput on one goes into input of the other = 15 ouputs) Use decent coax too:

http://www.maplin.co.uk/module.aspx?...No=275&doy=9m2

[vex]

Originally Posted by bigtim

They're called distribution amps.

Here's one at maplin (obviously only 8 way):

http://www.maplin.co.uk/Module.aspx?...%20amp&doy=9m2

Could poss use 2 of these to do the job (one ouput on one goes into input of the other = 15 ouputs) Use decent coax too:

http://www.maplin.co.uk/module.aspx?...No=275&doy=9m2

Sorry but they are domestic systems and are not designed for cascading from one amp to another without some form of attenuation. If you dont attenuate the signal then you open yourself up for all sorts of problems.

To be able to give professional advice we really need to know the layout of the building, how many floors, shortest and longest run from the riser on each floor and is it using original cable or a new install.

Oh and where are you, because the number of channels carried (including freeview multiplexes) has an affect on the amplifiers performance.

Once we have this sort of info, then we can give you good adivce along the lines that SamRadford has suggested.

HTH Chris

[SamRadford]

Well, the "star" arrangement could still work. You'd use a high quality (low noise) launch amplifier with suitable gain and 8 outputs. Each output could feed a good quality "Y" splitter. Make sure every star cable is the same length to equalise the signal at each room. A professional would regard this as somewhat crude but there's technically not much wrong with it!

First you need to look up the Field Strength of the appropriate transmitter at your location by using Wolfbane:
http://www.wolfbane.com/cgi-bin/tvd.exe?
Set the antenna height, type in your postcode and click GO.
Note the best transmitter's field strength and aerial group letter.

[vex]

I dont disagree with that Sam.

But cascading two domestic amps is a no no imo.

[SamRadford]

Yes, absolutely.

[Jagjock]

Originally Posted by vex

Sorry but they are domestic systems and are not designed for cascading from one amp to another without some form of attenuation. If you dont attenuate the signal then you open yourself up for all sorts of problems.

To be able to give professional advice we really need to know the layout of the building, how many floors, shortest and longest run from the riser on each floor and is it using original cable or a new install.

Oh and where are you, because the number of channels carried (including freeview multiplexes) has an affect on the amplifiers performance.

Once we have this sort of info, then we can give you good adivce along the lines that SamRadford has suggested.

HTH Chris

Thanks for that. There are 3 floors, four rooms at the top, five on the middle and six on the ground. The cable runs are approximately
4off @ 6m
5off @ 8m
4off @10m
2off @ 12m
Those are distances form attenna to receivers. Not quite sure what you mean by riser as I do a lot more plumbing than AV and my risers are 15mm copper pipes!

[SamRadford]

OK, assuming you are in the middle of Dorchester with a DT1 postcode, the analogue signal from Rowridge is around 48dBuV/m. For digital you'll need a Group "A" aerial. I suggest the Blake DMX10A since that's CAI approved and has a balun. it has (from memory) a gain of about 14dBd.

48 + 14 = 62dB (analogue) and the most your receiver will tolerate without swamping will be around 80dB so you'll need a masthead amplifier giving 80 - 62 = 18dB gain.

The Freeview signal is a measly 33dBuV/m but adding 14 + 18 gives a signal of 65dB which is just over the typical Freeview tuner threshold of 60dB.

12m of cable will reduce that to 63dB which is pushing it but should be OK. I'd be tempted to set the masthead amplifier to 20dB and add 3dB attenuators upstairs if the analogue causes dropout.

All of this is just theory of course! It just gives you a baseline from which to start. In practice things may be different, dependent on your actual poscode. The problem will be in finding a suitable amplifier system.

I've looked at Solutions Group offerings and I'd suggest doing it like this:

Very low noise Vision 13dB masthead Amp feeding a 47dB launch Amp (which can tolerate up to 119dB on its input). This would feed a 2 way splitter which would feed two 8-way splitters to give you your 16 outputs.

This is about the best I can come up with to achieve what you want.
You'd have to check on prices - I think Satcure can get all Solutions equipment.

Total cost should be well under £200 which would give you a per-outlet cost of £13 - which is pretty good.

[SamRadford]

Information overload?

[RB2004]

Hi, i work in a residential care home where i have been asked to convert the whole home to digital. I do not know if it is the correct way to install the system, but this is how i shall be doing it. So any feedback would be appreciated, and also hope this helps the person who created this thread.

There are 20 rooms

the building is aranged in a kind of L shape, so there is 2 separate roof spaces. one part of the building has 13 rooms, and the other has 7 + Sitting room

Bearing in mind it is a weak signal area, due to hils around the back.

So what i will be doing is rigging up a Televes DAT 75 Aerial, connected to a masthead amplifier with built in attenuator, then inside the roof space, it will be connected to a 2 way splitter.

From this splitter, one output will go to 1, 8 way distribution amp, and the other output till go to another 8 way distribution amp each of the 8 outputs will then have 2 way spliters connected to them, creating 16 outputs.. 13 will be used with 3 spare, the spare connections will have dummy load F connectors. All connections will be made with F connectors, and each output will go to a screened output wallplate. PF100 cable will also be used.

Only problem i need to figure out as i am no professional aerial installer,
is i dont know if its ok to have 2 power supplies going to 1 masthead amp, because each distribution amp has auto line feed power supplies for masthead amplifiers, and i have 2 distribution amplifiers, connected together via the 2 way splitter connected to the masthead amplifer. if that makes any sense. Also a potential electrical problem, is that the Distribution amplifiers are plugged in on different Phases so i will need to consult an electrician. as they will be connected via the 12v DC line feeds, which will be dangerous in a 230V AC situation as the voltage jumps to 430V