Earth leak affecting signal?

[Singlespeed]

Greets all, not sure I should be putting this in this section, but here we go...

On a terrestrial FreeView (TNT France) system with a dish running down the same cable via a splitter at the top and bottom, I can't get more than a 30% signal. This sucks frankly. I had it working for a while but it's now not getting enough down the cable to get a steady picture.

Here's why I'm in this forum: I keep getting small (and one slightly larger) shocks from the cables. French electrics are notorious so there may be an earth prblem on the whole house... If I use a standard multimeter, is there any way of testing what the 'leak' may be and tracing it?

This has been ongoing since about February!

 

[Vipersan]

Hi M8..
Not exactly sure what your configuration is ...
Are you saying that you are using the same cable for a terrestrial aerial and a satellite dish feed ...
With 2 receivers at the bottom of the single cable run ...
If so you are presumably using a diplexer arrangement ..
I personally would never use a single cable to double up its function ...you are to some extent asking for trouble...and I certainly would expect some gain loss /signal reduction.
Is it not possible to run another cable ?
As to the shocks you are getting ...what eactly are you getting them from ....the dish ..the aerial ..the cable ends ....the diplexer outlet ...or the receivers themselves ..??...and what else are you touching when the shock happens ?? a damp wall perhaps ?
most electrical appliances are only 2 core mains connected these days ...(some TVs plasma etc do have an earth)
Few small items such as set top boxes ...have an earth connection anyway ..though its not inconceivable there could be a potential difference between the various box cases (chassis or ground ) ...particularly as you have them joined together at the common cable ..
rgds

 

[Singlespeed]

there is only a single cable, routed through some small conduit, no chance of a second cable
Some of the tingles come from the cable, and some from the mast the dish and antenna are mounted on. The splitters are 2-in to 1-out, labelled SAT, TV, and IN/OUT, made by Konig?
I dont seem to need to touch anything else to get tingles. The recievers are a fairly old skybox and a new but low-end TNT box. I tried a different one and it was the same.

The thing is, looking at the OSD signal meter, when I plug the cable in to the TNT box, it flashes to 97% signal, the after a second drops to 30%. Some weird kind of capacitance?

 

[Vipersan]

Hmmm ....I'm gonna take a wild guess at whats happening/happened
Since the two boxes cases are not earthed through the mains ... there would effectively be a potential difference of a few volts between the boxes ...
Its likely that both the aerial and the dish/lnb are both isolated ...but very likely that moisture has infiltrated the diplexer at either the top end or at the wall connection ..
This can effectively earth the dish/aerial and again a potential difference is created realive to the set top boxes ..
The most likely point of your trouble.
You could then get a shock when connecting anything to this diplexed output ...and has the potential to damage the tuner in either box ...
(Always power down set top boxes when making the connection )
A damaged tuner would certainly account for the low signal ...as would moisture leakage behind the wall socket.
This would be the first point to check ...followed by the diplexer at the roof end ...then the aerial itself ..
Since the dish/lnb are isolated ...I'd consider this point blameless..
rgds
VS

 

[Singlespeed]

Well I changed the 'weathered' top splitter for a new out of the bag one, and got no signal at all. Nil. Nada.

What I can't get my head around is why it would be working a few weeks ago and now there's almost nothing. Most frustrating. This all started as a favour... :-HB and now looks like going down the ...

On another subject this site has the best collection of emotes I've seen...

 

[Vipersan]

I still favour water/damp ingress into the backbox of your wall mounted connection point ...
As to replacing the top end 'splitter' ..
Unless you replaced with the same time of unit ...
A simple 'splitter' isn't what you need ...
You need to combine/multiplex the 2 signals ...
rgds

ps
You may already know this ...but in case you don't ...
These are the sort of items you need ..
_http://www.satellitetv.ie/shop/index.php?controller=product&path=21_25&product_id=47

 

[Singlespeed]

Hmmm the url did'nt quite work... just gave Product not found ' on the website.
What I have is these _http://shop.satelliteonline.co.uk/signal-splitters-f-type-174-p.asp
Do I need something beefier?

 

[Singlespeed]

Found the diplexer thing... are they powered?

 

[Vipersan]

From what I saw regarding the device you're using ...
Its not a multiplexer
...and I suspect totally unsuitable for the job your doing ..
It would be suitable for just splitting a TV signal
..or splitting a satellite signal ...with control of the lnb on the power pass side ..
The other output being passive ...

not both at the same time ..

rgds

 

[Singlespeed]

Well that's not the best news I've had all day! Thanks for the help VS. That may well close off this thread...

 

[Vipersan]

Well you still can do the job if you get the right devices..
exterior multiplexer .....interior diplexer
hope I've helped..
rgds
VS

 

[Singlespeed]

Just took out the LNB input and the signal went to 80%. Still n ot getting all channels, biut I suspect that's it. Cheers!

 

[Channel Hopper]

Well I changed the 'weathered' top splitter for a new out of the bag one, and got no signal at all. Nil. Nada.

Some of the Global diplexers supplied through the UK had their labels on the wrong way round.

Additionally if the satellite receiver has a loopthrough then it is possible to ignore a diplexed wallplate and its inherrent losses, and loop the terrestrial receiver straight onto the back.

 

[Vipersan]

Just as an afterthought ...
I know your conduit is narrow ...but wondering if you might get single run of shotgun gable down it ?
Assuming ...the original gable moves freely ...it might have been possible if the path is wide enough ..to use the existing cable to pull the shotgun through..
Its the same impedance so you could in theory have your 2 seperate cables afterall..
rgds
VS

 

[Singlespeed]

Thanks both, but there is no way to get anything down the conduit. I think even a hoover/ piece of cotton, tie the cotton to a string, tie the string to a line etc would not work, too many corners.

Channel hopper, that sounded like greek to me... I really am a beginner at this!!!
Cheers chaps

 

[Singlespeed]

Just tried to order the diplexers / multiplexer set from Ireland.... €92 in postage alone!! Any suggestions?:-Nooo

 

[Vipersan]

Channel hopper, that sounded like greek to me... I really am a beginner at this!!!
Cheers chaps

He means like this ...
..but you will still need the multiplexer at the top end of the cable..
rgds