HOW TO FIND CABLE BEHIND WALLS (Non-destructive!!)

[strokebow]

Hi,

I am new on the forum.

Hope you can help me out.

Here's the situation. I know there are 2 TV aerial cables running down through my bedroom wall. (How? Because I have seen them run down in to the wall from within the loft space). One of them clearly goes to the TV aerial output socket directly below in the bedroom.
The question I ask myself is: where is the other one going. Well clearly its going down. And no doubt it is travelling through the wall down in to the ground floor front room. But there is no TV aerial output in that room. I believe (from looking at old plans) that the wire does actually run in to this room. I just want to find it and use it!!
Sounds simple enough but I dont want to go smashing plaster off walls to find it. I've already had some floorboards up in the bedroom but I cant see the wire going down the wall because there is a beam that is directly under the skirting board. So the wire running behind is definitely out of view.
Is there any way of knowing where it is? Any gadgets out there that can help you identify where the TV aerial might be?

Cheeeeeeeeeeers

 

[Diyisfun]

How long have you lived there?
Do you still have contact details for previous occupier?

 

[Sam Gangee]

It is possible to inject a modulated RF carrier into the cable and to use (for example) a small, portable AM transistor radio to detect the signal.

In fact a basic astable multivibrator will produce enough harmonics to be heard on a radio and can be put together in minutes (by anyone with sufficient knowledge of electronics). If the coaxial cable is sufficiently "leaky" (poorly screened) the high frequency harmonics will be detectable by a radio, anywhere along the length of the cable, provided that the radio can be held close.

(This presupposes that the end of the cable is not short-circuit.)

The (free) downloadable eBook "Beginners Guide to Electronics" contains a multivibrator circuit, which could easily be adapted:
http://www.The-Cool-Book-shop.co.uk/electronics.htm

 

[strokebow]

It is possible to inject a modulated RF carrier into the cable and to use (for example) a small, portable AM transistor radio to detect the signal.

Many thanks for your response and help!

However, how can I inject the RF signal into the cable when I cannot get to the end of it??
:-s

 

[Sam Gangee]

(How? Because I have seen them run down in to the wall from within the loft space).

^^^^^^^^^^^^^^^

 

[strokebow]

(How? Because I have seen them run down in to the wall from within the loft space).

^^^^^^^^^^^^^^^

haha

Yes, I have seen them but not the ends of them... because the aerial is on my neighbours house and the cables pass through the joining wall from his loft in to mine.

Do you think I should just cut the wire at the point where I can get to it, to inject the signal?

thanks again

 

[chapeau]

If you have an external wall where you want to place your new tele then bring a new cable down the outside and drill a hole where you want it to come in.

 

[Sam Gangee]

the aerial is on my neighbours house and the cables pass through the joining wall from his loft in to mine.

Do you think I should just cut the wire at the point where I can get to it, to inject the signal?

That would be safer than climbing onto your neighbour's roof to disconnect the cable end.

Then you'll need something like this: http://www.satcure.net/accs/page7.htm#jointkit