TV Aerial Install.

[Spudnik]

Chaps,

Just a quickie,

I have been asked to look at a block of 9 flats that require standard TV aerial points in each flat.

Anyone have any recommendations on tv boosters and the like?

Been using the SLx range, but would like something of a little more quality if such a thing exists.

Much obliged.

 

[Aok1]

Antiference or proception are abouth the best and both have vaiable gain and TETRA filtering.

Don't forget about using a good quality cable and earthing each coax.

 

[ian.settle1]

Chaps,

Just a quickie,

I have been asked to look at a block of 9 flats that require standard TV aerial points in each flat.

Anyone have any recommendations on tv boosters and the like?

Been using the SLx range, but would like something of a little more quality if such a thing exists.

Much obliged.

Amplifier which are designed for analogue TV signals may not work on digital Tv signals so check, last thing you will want to do is fit it all and then when it is all digital not work and you get told to replace at you own cost.

 

[Aok1]

There is no such thing as a analogue or a digital TV amplfier, dont let people rip you off by telling you there is. The only exception is for large system which may incorporate filters and very old amplifiers.

 

[Spudnik]

Thanks for that,

only trouble is, i cant find any with 9 outputs.

I am assuming ill have use an 8 alongside one with maybe 2 outputs or similar?

Ta

 

[Aok1]

Purchase a 8 way amplifier which has a 8 outputs including a full output, also purchase a 10 dB attenuator and fit this on the full theres your 9 output.

Dont daisy chain amplifers as it increases the amountof noise on the system. also fit fully screened outlet plates in the flats.

 

[Spudnik]

Thanks for that.

I never normally get that involved in aerials except domestic.

 

[andyb]

Don't forget about using a good quality cable and earthing each coax.

Aok1, what exactly do you mean when you say earth each coax?

I assume you just mean take the screen to the plate on the outlet.

 

[Aok1]

Aok1, what exactly do you mean when you say earth each coax?

I assume you just mean take the screen to the plate on the outlet.

No mate the actual braiding on the coax should be bonded to earth, this is acheived by taking a 4mm earth from the CU or pipework and then connecting in to a earth bar or earth kit on the amplifier.

This is a requirement of BSEN 60728-11, BSEN 50083-1 and a few others.

This was mainly a concern for commercial properties and blocks of flatthat have large systems.

This has now been brought into the domestic sector due to the high touch current that could be acheived by having several class II appliances connected together.

All coaxial cables should be connected to earth including aerial and satellite feeds.

 

[andyb]

That's interesting, at my niceic inspection last year I was picked up because I'd used a metal connector to couple a single ko box to a double. The double was for a socket & the single for a coax outlet.
The inspective said that this was introducing an earth and I had to remove the connector.
Since then I have kept them seperate, I need to look up the bsen numbers you quote.

 

[Aok1]

That's interesting, at my niceic inspection last year I was picked up because I'd used a metal connector to couple a single ko box to a double. The double was for a socket & the single for a coax outlet.
The inspective said that this was introducing an earth and I had to remove the connector.
Since then I have kept them seperate, I need to look up the bsen numbers you quote.

It's not un-common to find plenty of TV distribution systems without earths. The CAI (confederation od aerial industries) has plenty of info available on this subject.

To be fair TV systems is my field thtas what i have done for 12 years design and commision large TV systems projects, 95% of sparks dont know about it because it is only picked up by a aerial contractor that knows what they are doing and it is not common knowledge in the electrical trade.

The same now applies to coaxial cable they must be of a certain standard.

Andy i think with socket it may of been down to seperation issues but i know a couple of sparks who say there is no need for a earth for our outlets as they are plastic.

 

[Spudnik]

Is the current really that high to be worried about?

How does it find its way onto the coax?

 

[Aok1]

When a number off classII items are connected together the touch current can rise quite a bit, think of this in the living room - TV, Sky receiver, DVD, xbox, then in the bedroom a TV, freeview box and so on. They are all interconnected so that is how they derive at a current that maybe high enough.

For commercial say a 12 storey block of flats the same applies, also i have seen over the years a TV which had 130V ac floating around it caused by a faulty TV set. Many years ago when local aurthority installled communal aerials all of the outlets were isolated, a series of capicitors on the pcb. Virgin uses a simlar method with earthing of the splitter and galvanic isolation outside the property.