cat 5 cable

[fireman22]

i spoke to a guy this week who said that aerial guy's are now using cat 5 cable for tv socket work, as digital signal is better etc. anyone heard this? wondered if they are using it for all parts of the installation or just certain
parts

 

[MasterAbacus]

Hi, Cat 5 (Cat5e) is slowing become the norm to use to distribute tv around a house. Ive never come across an instalation that has the main feed...ie the ariel to fist device in anything other than coax.

Ive installed Cat5e, Cat6, Cat6e, Cat 7 and Cat 9 to distribute tv / entertainment throughout homes / offices etc.... its better than using coax for signal distribution, as you have the one cable with 4 pair (cat5e) so only need to run one cable for multiple feeds. Oh and the signal loss / interference is a little better than coax too.

Hope that helps.

 

[jwilliams]

Hmm... cat5 is a completely different type of cable to co-ax. I don't think it could be used as a direct replacement - co-ax prevents interference with the outer grounded shield, whereas cat5 requires the inverse of the signal to be carried in the second wire in the pair.

 

[Spark123]

I don't think it will be a direct replacement, I envisage there will need to be some converters from analogue to digital in there somewhere as well.

 

[MasterAbacus]

Hmm... cat5 is a completely different type of cable to co-ax. I don't think it could be used as a direct replacement - .

Yes, it certianly is different....LOL... Dependng on what kind of job your doing, its a much better option to use than coax for tv signal distribution.

theres a lot of Modern houses that are now being fitted with Cat5e or Cat6 points in everyroom.... For use as telephone / Internet or TV / Media connection points.

 

[MasterAbacus]

I don't think it will be a direct replacement, I envisage there will need to be some converters from analogue to digital in there somewhere as well.

In good quality new build houses, im pretty sure it will be used as a direct replacement for TV distribution, instead of coax.

And as for the need for Analogue to digital converters, then depending on what kind of signal your sending, very rare you need any special Analogue to digital converters..... Just the right Link-Up cables... ie, Scart to RJ45, or Bnc to Rj45.....etc etc

 

[RF Lighting]

I have wired PTZ cameras over cat 5. It enables you to have power, serial data and video running down a single cable rather than three seperate wires. This means you can utilise existing structured cabling already run within the building.

The ends of the cable is terminated with a video balun which has a BNC connector aswell as the terminals for power and serial data.

 

[MasterAbacus]

I have wired PTZ cameras over cat 5. It enables you to have power, serial data and video running down a single cable rather than three seperate wires. This means you can utilise existing structured cabling already run within the building.

The ends of the cable is terminated with a video balun which has a BNC connector aswell as the terminals for power and serial data.

Yeah works really well with CCTV systems too....

Simple answer is lots of devices / signals on only one Multicore cable....

 

[Softus]

...cat5 requires the inverse of the signal to be carried in the second wire in the pair.

This confuses me - could you explain how this method eliminates interference?

 

[plugwash]

the basic principle of a balanced line twisted pair system is that any interference hits both wires in the pair equally and so is easilly cancelled out.

coax is generally better for high frequencies though, i think you'd have great trouble getting UHF or worse satalite down twisted pair, compositive video could probablly be done without much issue with just the impedance and balanced/unbalanced conversions.

 

[Softus]

the basic principle of a balanced line twisted pair system is that any interference hits both wires in the pair equally and so is easilly cancelled out.

Sorry - I didn't mean to convey the impression that I didn't know that. I was referring to the part about the "inverse of the signal" in the second wire, which was news to me.

 

[jwilliams]

Interestingly, cat5 seems to be getting used as a general-purpose cable.

For some reason, my basic, 2-wire thermostat is connected to the boiler using cat5. All the solid wires to one terminal, all the white-striped wires to the other

 

[jwilliams]

the basic principle of a balanced line twisted pair system is that any interference hits both wires in the pair equally and so is easilly cancelled out.

Sorry - I didn't mean to convey the impression that I didn't know that. I was referring to the part about the "inverse of the signal" in the second wire, which was news to me.

That's certainly the principle of ethernet transmission, which cat5 was designed for.

It's not a necessity for other types of signal, but is does allow interference to be cancelled out using a simple algorithm.

 

[Softus]

I was referring to the part about the "inverse of the signal" in the second wire, which was news to me.

That's certainly the principle of ethernet transmission, which cat5 was designed for.

Another bit of news to me is that UTP cable was designed for Ethernet, in view of the facts that (a) Ethernet is not its only application, and (b) Ethernet existed long before UTP cable was used for LANs.

Also, Ethernet is a protocol, and doesn't dictate the transmission medium, although it's compatible with many. Moreover, since Ethernet was designed as a broadcast protocol, with provision for CSMA/CD, the expected medium is actually the antithesis of UTP cable, the topology of which is a star network instead of a bus.

It's not a necessity for other types of signal, but is does allow interference to be cancelled out using a simple algorithm.

I'm still concerned about this idea that the second wire of each pair (in a UTP cable) carries the inverse of the signal on the first wire. I remain unconvinced that such an idea is anything other than inaccurate conjecture.

 

[plugwash]

its not so much that the second wire has to be an inverse (in ethernet i belive the signal lines are are actually completely isolated from the system power rails so they probablly do end up as an inverse at least for the high frequency components) as that the receiver discards all common mode changes and only looks at the difference between the two wires.

and yes both ethernet and twisted pair predate ethernet over twisted pair though i belive cat5 was more or less designed specifically for fast ethernet.