Aerial Splitter


My mum has just got a freeview TV for her bedroom and the aerial signal is not good enough from the aerial in the loft, I presume because of the signal not passing through the concrete tiles very well, on her old analogue TV the picture was never up to much either! She has another aerial (on the chimney stack outside) that is connected to her downstairs set up, which includes a freeview STB, so I know this aerial signal is good enough. The outside aerial cable is on the roof and then down the wall and enters the house above her front door. Where the cable goes down the wall this is directly outside her bedroom window, so I was thinking of cutting the cable and putting a splitter in and running a new piece of coax in through the window frame corner. Can you get waterproof splitters any where or will I have to get a suitable box and put an internal splitter in there. I have look at Screwfix, Maplins and RS but cannot seem to find anything suitable.
TIA
John
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John wrote:

CPC do them
http://cpc.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU ¯CS1000&NA1
See thread in d-i-y group called "Aerial Spitters" too.
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Mark
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Before you cut the downlead I suggest that you fit a 6dB attenuator between the aerial lead and the STB. If the STB functions properly on all channels after this remove the attenuator and split the aerial as you propose. If the signal is not strong enough when doing this test you can still split the aerial but you will need some amplification or some other remedy.
Richard
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Richard wrote:

3dB attenuator would do as that is the same as splitting the signal in half
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On 8 Jan,

A /very/ good splitter would be unlikely to be less than 3.5db. A resistive splitter would be 6dB minimum. Testing with 6dB or even 10dB seems a very good idea to me. It will give an indication that signals won't be on the digital cliff after the aerial feed is split.
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®ÖÐ wrote:

No, halving the signal voltage would be 6dB (You're thinking of power ratios)
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Mark
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Mark Carver wrote:

OK, its just I have a passive splitter here on my TV and it says each output is 3.5dB less than input.
I take it the 0.5 is for insertion loss.
Than again I always get a bit confused when working with dBs
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John wrote:

I briefly tried those sorts of bodges, and then went for the far superior option of moving the aerial outside.
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The aerial I want to use IS outside, I just want to break into the cable and have it supplying two TV sets. I know it is possible as my own is split into three but the main bulk of my wiring is in the loft space or in the walls, so I didn't need an external splitter box. I know they are available as my In Laws have one on their house but there are no manufacturing marks etc that I can see and my father in law cannot remember who installed it.
Thanks for your input anyway!
John
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John wrote:

As,IIR, Richard suggested - it may be worth checking to see if the existing set can manage on the reduced signal.
IIUC, splitters come in three forms:
1) Cheap and nasty passive - basically a few resistors. Best avoided unless you can pick up stations on a coat hanger..
2) Low loss passive - using more expensive inductors to split the signal. Half the signal goes to each and very little is lost in the splitter, unlike (1).
3) Active (masthead amplifier) - which typically have a plug-in power supply at the downstairs aerial socket to power the splitter via the coax.
Whether you risk (1) or (2) - with or without trying an attenuator first to see the likely effect, or go straight to (3) - which /will/ work, is up to you and how much you like ladders.
At least with (3), if you ever want to feed yet another TV, it won't be a problem.
However, (1) and (2) are pretty immune to nearby lighning. Whereas (3) isn't. Not a problem if living in a valley with loads of houses/trees higher up to attract the nasties. But, if you live in Bleak House or look down on the plebs..maybe best avoided unless essential - although perhaps better the masthead box goes than the TVs..
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[2 way external splitter]

We have them in stock most of the time.
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AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems
http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk
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wrote:

How much are they incl p&p and do you have a picture, or a manufacturer and part no. so I can look at one on line?
TIA
John
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John wrote:

You wrote that there was one inside aerial and one outside; that is what I had as well. Splitting the outside aerial outside the house was a bodge. Moving the inside aerial to be outside and feeding one TV off each aerial was far superior, and in my case required no extra hardware.
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