Data loss over Cat5e cable

[bretherton]

I have just installed a 100 ft Mediabridge Cat5e patch cable to connect from my Router to my TV. My computer reports a download speed of 58 Mbps and upload of 38 Mbps when using a 6 foot patch cable to the router but this drops to about 14 Mbps/5 Mbps over the 100 ft patch cable. Is this typical or is the patch cable faulty?

 

[Someone Somewhere]

Did you terminate it or was it pre-terminated?

I'm guessing poor termination or cheap non-compliant cable.

Try forcing it to 100Mb/s instead of gigabit.

 

[bretherton]

Did you terminate it or was it pre-terminated?

I'm guessing poor termination or cheap non-compliant cable.

Try forcing it to 100Mb/s instead of gigabit.

 

[bretherton]

The cable came pre-fitted with RJ45 at each end and those are what I am using. I did not understand the part about 100Mb/s vs. gigabit and don't know how to force to 100Mb/s

 

[mbarnes86]

Hi

I was not aware modern ethernet cable (cat 5 or 6) could be terminated
Either cable is not cat 5e or it runs near a mains cable or other souce of interference .

If TV is not too large and heavy move TV next to router & use long 100ft cable & see what happens
cable lenght limit is 100m which is more than 3 x 100feet

simple cable testers just test continuity,
testing to cat 5 or 6 requires expensive equipment which profesional cable installers will have

regards
Mike Barnes

 

[bretherton]

Hi

I was not aware modern ethernet cable (cat 5 or 6) could be terminated
Either cable is not cat 5e or it runs near a mains cable or other souce of interference .

If TV is not too large and heavy move TV next to router & use long 100ft cable & see what happens
cable lenght limit is 100m which is more than 3 x 100feet

simple cable testers just test continuity,
testing to cat 5 or 6 requires expensive equipment which profesional cable installers will have

regards
Mike Barnes

Thanks. The Cat5e cable does run within about 4 inches of a mains cable for about 30 feet, is that close enough to cause interference?

 

[digitaldoc]

Interference should not be the issue. The ethernet cable sounds defective. I would try a different one.

 

[bill001g]

This is why I always test my patch cables before I run them someplace hard to replace. If this is a new cable you can try to exchange it at the store you bought it. If you had the ends and the tool you could replace the ends since is the most likely issue but you will pay more for the tool and the ends to make one cable than just buying another cable.

It would be nice if PC and routers showed you the rates the ports are running at and how many packets with errors you are getting but this is a very rare feature on consumer grade equipment.

 

[Someone Somewhere]

Most ethernet switches and NICs have lights for what speeds they're running at. Dropped packets is far harder, though.

 

[bretherton]

OK, so I bought a new 100 foot cable from a different manufacturer (also pre-fitted with RJ45s). Tested it before install (while still coiled up in its packaging) and got 58/38 Mbps throughput. Installed it running from the router located in the second story of my house down an outside wall to the crawl space and then through the crawl space to a TV in the family room. The installation involved no kinks or tight bends, no runs near microwaves or high voltage lines or even as far as I could see near to any 240/120 volt lines. After all this I got a similar result to that obtained with the previous cable (i.e. only about 11/5 Mbps). Any explanations out there? Would moving to shielded cable be worthwhile (though I don't know what I would be shielding against in this simple domestic install)?

 

[digitaldoc]

http://superuser.com/questions/582112/when-does-ethernet-cabling-need-to-be-shielded

Any fluorescent lights that you are passing? I would suggest doing the run with CAT 6 shielded cable at this point.

 

[bill001g]

Now you have a major mystery. Even cat5e cable in very resistant to interference. In the many years I have worked in this field having installed or been responsible for having others install many thousands of cable installed I have only seen 1 that was getting external interference. They had run the cable though a florescent light fixture next to the ballast.

Shielded cable is actually very hard to install correctly. The foil shield must be grounded on both end of the connection. If you do not ground it actually acts as a antenna and increases your interference. What you will see there are special rj45 plugs that have metal tabs on the side. Most equipment that is designed to use shielded cable has corresponding grounding connectors inside the jacks on the sides. You can use special couplers that let you ground the coupler if the equipment can no provide it. Still when you do it externally like this, not on specialized equipment, you run the risk of grounding loops. This happens for example when you would connect 2 buildings that the ground was not exactly the same. This is mostly a safety issue not so much a interference issues. Because this is complex and I have only had it required on telco equipment I have always had a certified electrician install it.

With the cost of the cable and to really get the grounding right I would be looking at low end switches and fiber before shielded cable if I was doing it myself.

Still this is extremely rare to see interference that degrades a cable.

Unfortunately you are at the point you need a special meter called a TDR. I have been looking for a cheap one for years for myself personally but they are expensive even used. These can actually see the interference and they can tell even what pair of wires is having issues.

 

[bretherton]

http://superuser.com/questions/582112/when-does-ethernet-cabling-need-to-be-shielded

Any fluorescent lights that you are passing? I would suggest doing the run with CAT 6 shielded cable at this point.

Thanks, but no fluorescent lights either.

 

[bretherton]

Now you have a major mystery. Even cat5e cable in very resistant to interference. In the many years I have worked in this field having installed or been responsible for having others install many thousands of cable installed I have only seen 1 that was getting external interference. They had run the cable though a florescent light fixture next to the ballast.

Shielded cable is actually very hard to install correctly. The foil shield must be grounded on both end of the connection. If you do not ground it actually acts as a antenna and increases your interference. What you will see there are special rj45 plugs that have metal tabs on the side. Most equipment that is designed to use shielded cable has corresponding grounding connectors inside the jacks on the sides. You can use special couplers that let you ground the coupler if the equipment can no provide it. Still when you do it externally like this, not on specialized equipment, you run the risk of grounding loops. This happens for example when you would connect 2 buildings that the ground was not exactly the same. This is mostly a safety issue not so much a interference issues. Because this is complex and I have only had it required on telco equipment I have always had a certified electrician install it.

With the cost of the cable and to really get the grounding right I would be looking at low end switches and fiber before shielded cable if I was doing it myself.

Still this is extremely rare to see interference that degrades a cable.

Unfortunately you are at the point you need a special meter called a TDR. I have been looking for a cheap one for years for myself personally but they are expensive even used. These can actually see the interference and they can tell even what pair of wires is having issues.

Thanks for the cautions about installing shielded cable, Maybe I will try replacing the RJ45s at each end of the new Cat 5e cable in case the connections inside were damaged during install.

 

[bretherton]

Problem Solved!
I now have the solution, the cable ran too close to a powered sub-woofer beneath my desk. I have relocated the cable so that this does not happen anymore and now get full 58/38 Mbps throughput at the TV end.

Many thanks to all who offered advice.

 

[digitaldoc]

Glad it worked out for you. Speakers with their magnets and coiled wires can definitely cause interference as well.