Co-ax Plate Help needed

[jselectrical]

I am an Electrician by trade but as part of my work I add aerial points and move Co-ax points. I have recently moved a sat & co-ax point in a living room but have kept the same cabling, albeit shorter run now. When I put a new sat + co-ax plate on the end of the cables I get no signal. If I put a f type connector and joiner on the sat cable I get near full sky signal strength. Does the plate need to be something in particular? I'm using a standard Click mode sat + co-ax plate.

Any help appraciated

 

[grahamlthompson]

Very often one Satellite and Terrestrial signals are diplexed onto a single cable. At the remote end the two sources are split into the two signals in the reverse process. Why can't you use the original plate with the required splitters ?

 

[Rodders53]

When I put a new sat + co-ax plate on the end of the cables I get no signal. If I put a f type connector and joiner on the sat cable I get near full sky signal strength. Does the plate need to be something in particular? I'm using a standard Click mode sat + co-ax plate.

Any help appraciated

Two possibles spring to my mind:
1) faulty wiring or installation - you've shorted inner to outer when connecting up or one occurs via the back box when screwed in

2) the plate is dc isolating the satellite feed - either due to a faulty plate or by connecting up to the wrong outlet socket


NB Unless the original feed is from an diplexed satellite and UHF TV distribution system the use of a splitter plate, if that's what you've installed, with the attendant losses of the filters, will reduce the signal available anyway.

Have you got one cable or two going to the plate? Has it got one or two cable connections on the 'install' side (we know it has two on the user side)?

 

[Boostrail]

There is an aspect I have recently found as am also in throes of major house changes and new aerial distribution system. (Aerial and cabling by me - F connector wall plates by sparks).

I have found that the sparks installs the metal patress alongside the mains patress and consequently the outer of the aerial cable is effectively connected to mains earth (if as it appears on the ones so far fitted the screws on the wall plates are at "outer" potential)

What effect this has I cannot test as yet* but seem to remember reading on here or elsewhere that the cable outer should not be directly earthed and should at least be decoupled?

*Still waiting for sparks to fit supply for distribution amp in loft.

 

[Rodders53]

What effect this has I cannot test as yet* but seem to remember reading on here or elsewhere that the cable outer should not be directly earthed and should at least be decoupled?

Sparks should seldom be used for professional aerial installations. Many have little idea about RF matters. Let's hope they haven't run the wires as a ring main.

The outer of the cables can earth bonded or grounded - and must be to meet IEE regulations in communal installations. (It is not an essential in a single-dwelling domestic install).

http://www.diybanter.com/uk-diy/84590-aerial-bonding.html is quite interesting.

 

[Boostrail]

Sparks should seldom be used for professional aerial installations. Many have little idea about RF matters. Let's hope they haven't run the wires as a ring main.

The outer of the cables can earth bonded or grounded - and must be to meet IEE regulations in communal installations. (It is not an essential in a single-dwelling domestic install).

Aerial Bonding - DIYbanter is quite interesting.

So from what you are saying a fully grounded outer on a coax or CT100 type cable is of no consequence? I have alwaays thought that the two should be at least capacitively decoupled.

PS am installing my own RF distribution system but am terminated in Sparks provided patresses and wall plates..

 

[Rodders53]

So from what you are saying a fully grounded outer on a coax or CT100 type cable is of no consequence?

Every cable connected to the DA is going to have the screens 'commoned' by the device (which will, if good quality, be metal-clad for screening purposes). If that unit has a 3-core mains lead it and they will be earthed, automatically.

Some loft boxes and multiswitches have dedicated earthing posts - especially those that may be used for multi-dwelling installations - so that all the components are readily 'equipotential bonded'.

 

[Boostrail]

If that unit has a 3-core mains lead it and they will be earthed, automatically.


.

I have not seen an AV product with a three core mains lead since my grand- daughters father was a 5 year old ! (i.e. late eighties)??? Many have "moulded" UK plugs with dummy earth posts to open access plates on socket for L and N???