STP or UTP, in regards to Home Theater, Home Networking and HDMI over Ethernet ?

[ahmadka]

Hi guys, so I have another confusion to settle .... I need to know if I should use STP or UTP cables for connectivity in my home. Done significant reading on this already, and it seems that STP cables are generally recommendable for outdoor or industrial use, or where "there's a lot of RF interference". Problem is, I don't know if the 3rd clause applies to me or not. I say this because in my HT room, I have a 4" tall skirting running all around the room which will be used for cabling placement. Inside this space, I will have a bunch of cables running, which includes HDMI cables (2 or 3), Ethernet (4 or 5), USB cables (2 or 3) and Power cables (2 or 3). The Power cables I'll use will be shielded, however I don't know if that will be enough or not. Would this close proximity to a shielded power cable warrant the use STP over UTP ?

Within my HT room, I'll also be running Ethernet cables for HDMI over Ethernet use in the future, so I need to know if STP is really needed for this or not.

Additionally, I also want to network internet connectivity for all floors in my home (4 floors), and will be passing the cable through conduits inside walls. The conduits may or may not come close to any power cables.

So given all this info, should I use STP or UTP ?

STP cables also seem to require grounding for effective use. I honestly don't know if I'll be able to ground them or not.

 

[kevnich2]

You need to use UTP.

Shielded cable is only used when you KNOW you need it. This is really only for Manufacturing environments where there's alot of electrical RF interference. The shielding shields this. If you use it in the wrong environment and don't terminate it properly, you're asking for ALOT of issues.

 

[Emulex]

http://www.biamp.com/blog/when-should-you-use-shielded-vs-unshielded-ethernet-cable/

http://electronicdesign.com/components/how-determine-when-shielded-network-cabling-required

goes over shielding for low smoke - no fire jacketing as well.

 

[ahmadka]

You need to use UTP.

Shielded cable is only used when you KNOW you need it. This is really only for Manufacturing environments where there's alot of electrical RF interference. The shielding shields this. If you use it in the wrong environment and don't terminate it properly, you're asking for ALOT of issues.

But since the power and data cables are all grouped together, won't the power cable cause RF interference ?

http://www.biamp.com/blog/when-should-you-use-shielded-vs-unshielded-ethernet-cable/

http://electronicdesign.com/components/how-determine-when-shielded-network-cabling-required

goes over shielding for low smoke - no fire jacketing as well.

Have already seen the first of those links. Will read through the second one.

 

[azazel1024]

It can.

It isn't likely too. I've run ethernet bundled with power wiring over a distance of a good 50ft in the past (because it HAD to be done). No detectable impact on the wiring run. Granted, only doing 1000BASE-T, maybe with 10GIGABASE-T there might be enough interference to cause problems.

I just don't see it likely to be happening. Most of the interference you are generating is not in the relevant frequency range for ethernet operation (125MHz for 1000Base-T, 600MHz I think for 10GIGABASE-T), you are generating interference at 60Hz from power wiring (or 50Hz, not sure where you are). HDMI is also at a vastly different frequency than Ethernet.

Shielding is generally for one of two things.

Alien cross talk from OTHER ethernet wires or from RFI interference in an environment where you might have RF generated in the ~125MHz range. Cat5e is designed to handle wiring bundled of DOZENS of Cat5e wires bundled together operating at 1Gbps/1000Base-T to a length of 100 meters. A few dozen feet with a few HDMI, ethernet cables and some power wires bundled together shouldn't be an issue at all. If you are that worried about it, run Cat6 instead of 5e. It utilizes tighter pair twists, which reduces interference along with often having the pairs seperated, which also helps reduce interference.

Higher standards are only more stringent and later upping to various levels of shielding because they have to handle even higher frequencies, which also means higher levels of attenuation which means that much more suceptible to any kind of interference (primarily from alien cross talk, or even internal cross talk, IE the adjascent wire pairs within a wire producing interference in each other).

Shielding is really just for specialized cases (cat6a+ and/or industrial/scientific applications where there WILL be real interference).

 

[seepy83]

I installed some HD-BaseT (HDMI over Cat6) stuff a couple of years ago. At the time, all of the documentation and recommendations I read said to use STP. The product I was using (don't recall exactly what it was) was designed to use patch cables between the transponder and receiver ends. I bought pre-terminated STP patch cables to meet their requirements/specs.

Looking over the HD-BaseT docs I can find online now, it looks like they're not saying to only use STP anymore.

 

[ahmadka]

Thanks for that. Given that info, I think it would be better if I just went with UTP after all ..

What about factory made short STP patch cables (various lengths between 3 ft ~ 15 ft which I've already purchased from Monoprice) ? Is it okay to run them in parallel alongside long UTP cables and a few power cables within the same 4" tall skirting running around the HT room? Or should I use UTP cables in their place too ? I ask because I read somewhere that STP cables can 'attract' interference and possibly cause problems in nearby cables too. I just don't know if this occurs in the presence of factory made STP cables or not.

Also, do factory made STP cables also require grounding ? I don't see any ground wire coming out of them which you'd connect to ground.

 

[kevnich2]

Thanks for that. Given that info, I think it would be better if I just went with UTP after all ..

What about factory made short STP patch cables (various lengths between 3 ft ~ 15 ft which I've already purchased from Monoprice) ? Is it okay to run them in parallel alongside long UTP cables and a few power cables within the same 4" tall skirting running around the HT room? Or should I use UTP cables in their place too ? I ask because I read somewhere that STP cables can 'attract' interference and possibly cause problems in nearby cables too. I just don't know if this occurs in the presence of factory made STP cables or not.

Also, do factory made STP cables also require grounding ? I don't see any ground wire coming out of them which you'd connect to ground.

STP cables usually a special RJ45 termination that's all metal that connects to the shielding and sometimes even a drain wire that attaches to the terminator. This then grounds to the female adapter it plugs into. If you use STP without the proper grounding, yeah it attracts interference, can create ground loops, etc. Again, you only run STP when you're told or know you need to run STP. If you use it just because, you're going to cause more issues.

 

[Emulex]

You can wrap your UTP wiring in a foil based sheath to prevent crosstalk from outside sources.

 

[azazel1024]

You can wrap your UTP wiring in a foil based sheath to prevent crosstalk from outside sources.

That has to be grounded though. If you don't ground it, you are just creating a big antenna. Same principal around STP and not properly grounding it (and ONLY on one end, otherwise it can create a ground loop).

Improperly terminated STP leads to ground loops or additional interference.

Properly terminated STP is simply more expensive than UTP and can reduce interference. If you don't need to reduce it, it is simply expensive and a pain.