TV Aerial splitting
Discussion
So now I have a new telly, and somoene is going to lend me a digibox so I can see if we get freeview. I need to sort out getting the signal round the house.
Currently the Aerial is on top of a pole on the chimney, the cable then comes down the roof, into the house and into the sitting room and the telly. The picture quality on here is very good. I have then put an extention from this box through to the other sitting room where the other telly is which is. The signal is not so good by the time it gets here.
What I'd like to do is take a three way splitter take a feed each into each sitting room and one into the bedroom.
If I split the cable in the loft in two and take one downstairs and the other to the bedroom then extend the downstairs one to the other room will that work ( I think not as the signal loss is already quite high) or should I split it three ways in the loft then run seperate feeds? If I spilt it will the quality degrage? Should I use an amplifier?
Can anyone recommend which coax to use as I'm probably using some stugg I had left over from a network install which might not be the most ideal and therefore be the reason for my signal loss in the second sitting room.
Questions, questions...
Cheers
D.
Currently the Aerial is on top of a pole on the chimney, the cable then comes down the roof, into the house and into the sitting room and the telly. The picture quality on here is very good. I have then put an extention from this box through to the other sitting room where the other telly is which is. The signal is not so good by the time it gets here.
What I'd like to do is take a three way splitter take a feed each into each sitting room and one into the bedroom.
If I split the cable in the loft in two and take one downstairs and the other to the bedroom then extend the downstairs one to the other room will that work ( I think not as the signal loss is already quite high) or should I split it three ways in the loft then run seperate feeds? If I spilt it will the quality degrage? Should I use an amplifier?
Can anyone recommend which coax to use as I'm probably using some stugg I had left over from a network install which might not be the most ideal and therefore be the reason for my signal loss in the second sitting room.
Questions, questions...
Cheers
D.
Definitely use an amplified splitter in the loft. You will get pants signal if you just split the coax with regular splitters not least because the splitters themselves lose a lot of signal internally.
You can get satellite grade co-ax cable - the cheapest place I know is www.screwfix.com
In my old place I had a "TV-Link" for Sky Digital - this gives you a little remote control receiver for each TV. I did it with standard co-ax and the cable had to be very carefully laid (i.e. no sharp bends) otherwise insufficient power would get through to power the receiver. In my new place, the Sky man used proper Sat grade cable and it can go round tight corners with no problem. Not sure if TV-Link (www.tvlink.co.uk) will work with Freeview boxes. If it does, it is well worth it!
Golden rules - use good cable and try to make each length of cable continuous - i.e. no joiners to fit 2 bits together. Also avoid using a socket plate as all these things equal signal loss.
HTH
You can get satellite grade co-ax cable - the cheapest place I know is www.screwfix.com
In my old place I had a "TV-Link" for Sky Digital - this gives you a little remote control receiver for each TV. I did it with standard co-ax and the cable had to be very carefully laid (i.e. no sharp bends) otherwise insufficient power would get through to power the receiver. In my new place, the Sky man used proper Sat grade cable and it can go round tight corners with no problem. Not sure if TV-Link (www.tvlink.co.uk) will work with Freeview boxes. If it does, it is well worth it!
Golden rules - use good cable and try to make each length of cable continuous - i.e. no joiners to fit 2 bits together. Also avoid using a socket plate as all these things equal signal loss.
HTH
Hi David,
Did almost the exact same thing just a few weeks ago. Found that you needed a booster amp to make the picture any good. Perhaps a three way booster would do the trick...? You can get distribution amps from B&Q now - that's where I bought the one the other week. There's also masthead amps which amplify the signal at the antenna. The best amp would be a variable gain device and one which boosts just TV frequencies, not 0-1000MHz. I bought one years ago, but haven't been able to find another since.
Did almost the exact same thing just a few weeks ago. Found that you needed a booster amp to make the picture any good. Perhaps a three way booster would do the trick...? You can get distribution amps from B&Q now - that's where I bought the one the other week. There's also masthead amps which amplify the signal at the antenna. The best amp would be a variable gain device and one which boosts just TV frequencies, not 0-1000MHz. I bought one years ago, but haven't been able to find another since.
So now I have a new telly, and somoene is going to lend me a digibox so I can see if we get freeview. I need to sort out getting the signal round the house.
Currently the Aerial is on top of a pole on the chimney, the cable then comes down the roof, into the house and into the sitting room and the telly. The picture quality on here is very good. I have then put an extention from this box through to the other sitting room where the other telly is which is. The signal is not so good by the time it gets here.
What I'd like to do is take a three way splitter take a feed each into each sitting room and one into the bedroom.
If I split the cable in the loft in two and take one downstairs and the other to the bedroom then extend the downstairs one to the other room will that work ( I think not as the signal loss is already quite high) or should I split it three ways in the loft then run seperate feeds? If I spilt it will the quality degrage? Should I use an amplifier?
Can anyone recommend which coax to use as I'm probably using some stugg I had left over from a network install which might not be the most ideal and therefore be the reason for my signal loss in the second sitting room.
Questions, questions...
Cheers
D.
You need a signal booster - the aerial plugs into this and has several outputs which allow you to run a number of TVs at a better signal strength.
If you are getting a digi box remember that it will only output one channel at a time, much like a satelite system - why they can't just convert the whole signal to analogue and allow the TV tuner to select the channel I don't know
If you are getting a digi box remember that it will only output one channel at a time, much like a satelite system - why they can't just convert the whole signal to analogue and allow the TV tuner to select the channel I don't know
Any splitting has to be done as close to the aerial as possible, usually the loft although there are external ones for extreme cases.
Use good quality cable suited fo TV use. The impedance is important here as there are several types of co-ax. Be careful of the bends in the cable. Too tight and it affects the signal and can break the cable. Solder any connectors, pins (center conductor) that is.
Try Argos for the amps/splitters as you can take them back if you are not happy and try another one.
Use good quality cable suited fo TV use. The impedance is important here as there are several types of co-ax. Be careful of the bends in the cable. Too tight and it affects the signal and can break the cable. Solder any connectors, pins (center conductor) that is.
Try Argos for the amps/splitters as you can take them back if you are not happy and try another one.
miniman said: Suspect you won't get cheaper than this:
www.screwfix.com/app/sfd/cat/pro.jsp?ts=36494&id=17158
When they say masthead do they mean it goes on the aerial or that I can have it in the loft?
What sort of power draw will it have?
What rating shold the cable have ? 75 or 100ohm?
thanks
D.
I think that means that as well as being a standard 4-way amp, it will ALSO power a separate masthead amp (so you have less power point requirements in the loft).
Suggest this cable would be OK, also very cheap compared to the "per metre" price you will get in Homebase et al.
www.screwfix.com/app/sfd/cat/pro.jsp?ts=36935&id=13956
Suggest this cable would be OK, also very cheap compared to the "per metre" price you will get in Homebase et al.
www.screwfix.com/app/sfd/cat/pro.jsp?ts=36935&id=13956
If you do not what the freeview in every room then you mite just as well get you self some more aerials and mount them in the loft (this is not to expensive ether).
The two things you need to avoid is splitting the signal (you should be able to run two TV from one aerial) and connectors. For every joint you have in the signal path you will get loss. Old cable and aerials oxidize and reduce signal to so replacing them can help.
The two things you need to avoid is splitting the signal (you should be able to run two TV from one aerial) and connectors. For every joint you have in the signal path you will get loss. Old cable and aerials oxidize and reduce signal to so replacing them can help.
jmorgan said: Mast head amps (external ones) are for extreme problems. Up some dark vally on the limits of a fill in transmitter.
Whats the reception like with you?
>> Edited by jmorgan on Tuesday 14th January 09:53
>> Edited by jmorgan on Tuesday 14th January 09:55
We are in a bit of a valley (if they have those in Cambridge) but the picture quality on the first TV is excellent so I thnk the actual signal is good.
I have a feeling that the cable I used to run the feed into the second room is a bit crap so I'll probably start by swapping it for decent cable and soldering all the connections.
what about taking another cable directly from the aerial? Will that degrade the signal?
D.
Two reasons.
AJLintern said:why they can't just convert the whole signal to analogue and allow the TV tuner to select the channel I don't know
As already stated, digital TV is compressed using a standard called DVB which is essentially MPEG compression. MPEG decompression is not a trivual task - taking around 250-500 million operations per second to perform.
The cheapest DSP that can do that sort of calculation is in the £10-20 in volume. To therefore do all theortical 700+ channels you would need 700 of those, or to just do the 20 channels or so that are already on there would put the cost of the decoder DSP's at £400. Retail it would be over £1500. To that end it's not considered viable.
To put it in perspective - the latest £1500 PC has only the "grunt" to do 4 of "home TV" quality (around 2Mbps).
However, there are other reasons.
To offer more than one channel so you can change channels on the TV, you would need to change the digital decoded 2Mbps+ signals into the standard PAL encoding specification. That is limited to ~5Mhz of analogue bandwidth. To properly encode the 2Mbps of digital data into an analogue signal to ensure the same quality then you would need at least 50Mhz of analogue bandwidth.
Finally - you wouldn't be able to get all the channels on the analogue signal. To stop TV signals interfering with each other, you need to firstly have a very good RF stage that doesn't "leak" too much (to gain "broadcast" quality to pack the channels together as closely as they do currently would take a design that in itself would cost >£50) you need to space the signals out. This spacing leaves only enough room for ~12-15 channels - consequently you couldn't get all the channels anyway!
Couple that with that you would need to not clash with the existing broadcasts (that vary as you move over the country) and it's not going to work!
Hope that answers your question!
J
Nice one Joust. I was considering going off on a technical explanation like that but haven't any facts 'n' figures to hand to back it up! Also, somebody mentioned Sky+ boxes. Don't know about decoding more than one channel at once, but recording is fine, as it records the compressed data stream to HD and decompresses it when you're watching it. Therefore, can theoretically record as many channels as the dish is can receive at once (depending on cabling and speed of disks etc).
This, to me, makes it a better system than Tivo simply because you'd have to (a) receive the signal, (b) decode it, (c) send it to the Tivo box, (d) recompress it again for storage and (e) decompress it again to watch it... all at 1 chnnel at a time.
Rotaree said: Joust you never cease to amaze me!! As well as being a fine legal eagle when required you also seem to be a television engineer - is there no end to your talents?!
Electronics is my speciality - I trained as an electrical and electronic engineer, used to design 64 parallel processor image processing machines (for the MOD - very scary stuff they did with it), IBM PC's that you could fit into small spaces, broadcast graphic systems, laser printer control engines and have been known to do the odd silicon chip design as well in my spare time.
Post that I'm just a nosy bugger that has run my own company (and hence gained a good knowledge of employment law, accounting etc.) and had many a job in business and product development for the last 5 years so I've hung around with a lot of clever people.
Oh - and I use google a lot (which anyone can do) - most of what you need can be found out there and then you too can look dead smart
J
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