What sort of Cable?

Originally Posted by Proppinupthebar

Cable uses something like 100MHz upto 800MHz. Satellite uses between 900MHz and 2GHz. The coax for each is designed specifically for the use.
CT100 will work but may not have the low loss specified in the cable frequency range.

As MB says tho, don't mess with it.

CT100 has a loss of 0.064dB/m @ 100MHz & 0.21dB/m @ 1000MHz
RG59 has a loss of 0.13dB/m @ 100MHz & 0.46dB/m @ 1000MHz

CT100 is used widely for DTT installations too, as the double screen prevents impulse interference from entering the signal path which could cause momentary pixellation or sound chirp.

Originally Posted by XFS03

CT100 has a loss of 0.064dB/m @ 100MHz & 0.21dB/m @ 1000MHz
RG59 has a loss of 0.13dB/m @ 100MHz & 0.46dB/m @ 1000MHz

CT100 is used widely for DTT installations too, as the double screen prevents impulse interference from entering the signal path which could cause momentary pixellation or sound chirp.

I stand corrected I've always know CT100 as satellite cable. Its blatantly not!

Have you got specs for RG6 and RG11? I'd be interested to see them.

Originally Posted by Proppinupthebar

I stand corrected I've always know CT100 as satellite cable. Its blatantly not!

Have you got specs for RG6 and RG11? I'd be interested to see them.

Generally, satellite cable will work at TV frequencies and give a much lower loss than 'normal' TV coax. A cable which is designed to give low loss at 2GHz will give even lower losses when used at lower frequencies, as shown in spec tables.

The problem when using some satellite cables for TV use, is their inflexability. Generally, the lower the loss, the thicker the cable, so they become very hard to handle. CT100 is a good compromise (IMO).

I've found a few sites with tables for various cables. The figures I quoted in my previous post, were from the Maplin catalogue. Depending on the manufacturer, the figures for the same cable can vary slightly.

http://www.epanorama.net/documents/video/videocoax.html
http://www.satcure.co.uk/tech/cablespecs.htm
http://www.wessexcdt.co.uk/coaxct.htm#specs

[Mr_Burns]

ntl uses RG-6 internally. I've only seen RG-59 used on very rare occasions. And it's of a much better quality than some RG-6 cable you can buy. I've seen cable which is labelled as RG-6 but is not even screened and on further investigation has a much higher attenuation than the cable ntl uses.

The loss for ntl's RG-6 internal cable is 0.1854dB/m @ 750MHz and something like 0.05dB/m @ 65MHz

[altis]

There's masses of info on cables here:
www.belden.com

click on products, then Belden catalog and the technical info.

RG-59, RG-6 and RG-11 are just different classifications of cable. There are plenty of options within each class although they are broadly similar. Belden call them Series-59, Series-6 etc. I'm not sure which manufacturer NTL uses - probably not Belden as they are probably the most expensive!

[orangebird]

Originally Posted by altis

There's masses of info on cables here:
www.belden.com

click on products, then Belden catalog and the technical info.

RG-59, RG-6 and RG-11 are just different classifications of cable. There are plenty of options within each class although they are broadly similar. Belden call them Series-59, Series-6 etc. I'm not sure which manufacturer NTL uses - probably not Belden as they are probably the most expensive!

Yes, we DO use Belden.

[altis]

LOL - my apologies!

I think it's time for a universal re-classification of coaxial cables.

It gets a bit silly when you can't just go by the RG number to select your cable.

I notice on the Belden site, that their RG11 cable is listed as only having a nominal loss of 12.37dB/100m (13.88dB max) @1GHz, whereas the Maplin RG11A/U has a loss of around double that at 25.5dB/100m @1GHz.

As for ntl using Belden's RG6, which one of the 59 types of RG6 cable do they use?

[Mr_Burns]

Originally Posted by orangebird

Yes, we DO use Belden.

Not for drop cables or distribution coax cables though - they're supplied by Commscope.

The attenuation figures for the Belden RG-11 are almost, if not identical, to the Commscope RG-11. I think, and don't quote me, that drop cables are single screened, but cables used in the headend/hub are double screened.

[t31os]

So for those of us still confused can we narrow it down to a cable?

I want to move my cable across the room, i currently only have about 1 metre of cable from the splitter to the box (and we asked for at least 4 metres on the install), damn stingey engineer handily forgot this when he was installing and only had a few metres on him when he arrived (apparently).

So just to narrow it down, because i'm not waiting god knows how long for an NTL engineer to come, which cable will i need to use?

Sorry to a bit bashy, but i'm re-decorating the front room and i have literally 2 days to go out, get cable and put it down.

I'd appreciate it big time if anyone could email some information regarding the necessary cabling, i should also mention i have broadband, of which has enough cable for now, but would also appreciate advice for cable should i want to replace in the future.

Please send info to munksmadness(at)hotmail(dot)com

Thanx anyone that can help

[jtwn]

IIRC, when i extended by about 5m i got some RG6 with f-type couplers and that did the job fine.

[t31os]

Whats the best place to buy thos bits in the UK?.........

I got 2 days, i could'nt see RG6 on maplin, did i miss them or should i be looking elsewhere?

[Tezcatlipoca]

Originally Posted by t31os

Whats the best place to buy thos bits in the UK?.........

I got 2 days, i could'nt see RG6 on maplin, did i miss them or should i be looking elsewhere?

From earlier in the thread....

http://www.cableforum.co.uk/board/sh...06&postcount=9

Originally Posted by XFS03

My internal cable is CT100, which is double screened satellite grade coax and has half the loss of RG59.

Maplin sell it as FT100. It costs twice as much as the RG59, but I would recommend it.

Maplin code is XS17T for white and XS16S for black @ 99p per metre.

A quick search of the Maplin site failed to find FT100, but they do have...

http://www.maplin.co.uk/Module.aspx?...ID=2&doy=24m10

Originally Posted by Maplin's

Low Loss Satellite Cable FT125
-


Uprated version of FT100 XS16S. 5-celled polyethylene insulator. Sheathed overall in black PVC. Compatible with CT125 cable and connectors.

They also sell F plugs.

It'd probably be better to go in a Maplin store & get a cable made up properly (costs a fiver I think), rather than put the connectors on yourself....unless you have the correct tools & know how to do it properly.

Originally Posted by Matt D

...A quick search of the Maplin site failed to find FT100, but they do have...

http://www.maplin.co.uk/Module.aspx?ModuleNo=278&TabID=1&source=15&WorldID =2&doy=24m10

The "new, improved" Maplin website is pretty useless!
They do still sell the FT100 cable (it is actually listed down the left-hand side of the link you provided). However, doing a search for it produces no results!

Also there are no specifications given for either cable. Very useful.

The specs. in the printed catalogue are as follows:-
FT100 overall diameter = 6.6mm / nominal conductor area = 1 sq mm / impedance = 75 Ohms / attenuation per 100m = 6.4dB @ 100MHz and 21dB @ 1000MHz.

FT125 overall diameter = 7.8mm / nominal conductor area = 1.25 sq mm / impedance = 75 Ohms / attenuation per 100m = 4.9dB @ 100MHz and 18.74dB @ 1000MHz.

[t31os]

Thanx guys.......