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.
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.
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.
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
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!
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
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..
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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