Extending virgin media cable.

[Steve]

I know I need the decent stuff (WF/CT100), but I need to extend both TV and broadband by about 5 metres.

At present there is a short run at the main outlet into a splitter marked 3.6dB and 4.0dB. the 4.0dB outlet supplies the superhub, the 3.6dB to the TV. On the superhub inlet is a 15dB forward path attenuator. On the TiVo box is a 10dB forward path attenuator. I have no idea what these are or what they do, so . . .

Does any of this affect me extending the outlet from the wall before the splitter by about 5 metres with a length of good quality cable? My thought being that these attenuators are installation specific based on some measurement of signal etc, that extending the cable would change.

And what do these attenuators do?

 

[plugwash]

I doubt a few meters more cable will make any noticable difference to signal levels.

 

[kjacko]

I've done it a few times using CT100 and it's been fine.
Even done it outside the house, used f-connectors then a coupler and then, laughlingly i wrapped black masking tape around it.
It was fine, until we had sky installed which did away with it.

 

[Lucid]

Virgin uses a triple shielded cable called Webro HD100. The shielding is as much to do with preventing interference radiating from the cable as it is to do with stopping external interference.

The electrical performance of HD100 is very close to Webro WF100.

 

[Steve]

It's very stiff cable. The routers position is determined by the cable.

 

[Lucid]

Yes it is. I ran some this weekend in preparation for the Virgin installers visit.

Ultimately it's your choice what you do. But if you find that you're picking up interference on other devices, or there's signal issues with the Virgin gear then you'll end up re-doing the work.

 

[Sam Gangee]

As it's a rental system it belongs to Virgin so do their T&Cs actually allow you to tamper with it?

 

[kjacko]

As it's a rental system it belongs to Virgin so do their T&Cs actually allow you to tamper with it?

good point actually.

 

[Jaidge]

As it's a rental system it belongs to Virgin so do their T&Cs actually allow you to tamper with it?

Yes, you're allowed to disconnect the equipment and replace the cable from the box to the wall.

The cable is "given" to you as part of the installation service, as such it is the only part which you actually own. The cable box, the attenuators, wall inlet thingy and your router all belong to Virgin. They normally ask for the kit back once you end the contract but they don't tend to charge you for replacements if you damage anything, so bodge away!.

The cables are rated for lengths of 100M+ with no impact to signal strength, so an additional 5M will make no difference whatsoever, provided you use high quality shielded stuff.

 

[Sam Gangee]

The cables are rated for lengths of 100M+ with no impact to signal strength

"No" impact? With attenuation of around 15dB at 600 MHz, I'd have thought the impact would be fairly significant. If I attenuate my UHF TV aerial signal by 15dB I lose all channels.

 

[Jaidge]

If I attenuate my UHF TV aerial signal by 15dB I lose all channels.

Correct.

However we're not talking about a UHF TV aerial signal here, we're talking about digital cable which carries a much stronger current.

He has attenuators already attached to his system, so could comfortably extend by 500M or more by removing them.

Bear in mind this cable has to run outside, underground, typically all over the outside walls your house etc. before it reaches you, sometimes distances of several KM. A few extra metres is not going to affect it whatsoever.

 

[Sam Gangee]

we're talking about digital cable which carries a much stronger current.

There's no such thing as "digital cable". It's coaxial cable. And it carries an RF signal - no DC current.

He has attenuators already attached to his system, so could comfortably extend by 500M or more by removing them.

How many will he have to remove for a 5m extension?

 

[Jaidge]

There's no such thing as "digital cable". It's coaxial cable. And it carries an RF signal - no DC current.

Yeah, I'm aware of that, but it's carrying a digital cable TV / internet service is what I meant. Typically when people talk about cable coming in to their house they're either referring to the old analogue cable TV service or the more recent digital cable tv service which Virgin Media do. So when people say "digital cable", they're referring to the content being delivered, not the actual transmission mechanism of the wire.

Sorry for my use of colloquial language to describe what is a very simple idea. I'll be more precise and overcomplicate it for you:

Yes but we're not talking about a UHF signal from your TV aerial, we're talking about a 300-600Mhz signal coming through fully shielded high-spec coaxial cable which is fed from a very high specification head end RF amp and intermediate RF amps which are spaced at regular intervals (usually at least 1km) and buried underground. It has a much stronger signal with a better SNR than OTA TV and suffers from significantly less interference.

Better?

How many will he have to remove for a 5m extension?

Zero.

 

[Steve]

When I moved into the house I ripped out 2 Virgin media outlets in the bedrooms, and the associated cabling around the outside of the house. I didn't keep any of it unfortunately.

If I buy a length of Webro HD100, what connectors do I need on the ends? The virgin ones don't appear to be crimped or anything, are they screw on? I don't have any special tools or anything.

 

[Sam Gangee]

WF100 is perfectly adequate and 'F' plugs are available.