Wireless Interference?

[OMaraSTO]

Could signals from a Wireless networking (802.11b) hub cause interference with nearby cat5 cabling?
I have a cat5 cable which runs right next to a 3com wireless hub, and am having problems with the cable link: The cable tests OK on cable testers, and gives a link light in the back of the PC, but no activity lights, and I can't get it to see the network. I'm thinking it's losing the data because of interference?
Any thoughts?

Thanks

Steve

 

[Grenage]

Is it possible for you to Turn off the wireless access point for a brief period to give you a definate answer ?

 

[daronwilson]

I'd be quite suprised if the low power wireless gear would do that, but anything is possible in cabling. Good suggestion to turn off the AP and see if the problem goes away. You say the cable tests ok, what are you testing it with?



It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[OMaraSTO]

The problem I have is that I am based at head office, and the site in question is quite a long way away, so I can only get over there myself on a limited basis. I have asked an end user at that end to try unplugging the wireless box, but am still waiting a response on that (trouble is it is an end user, and I might not get the whole story)
I'm using a 'Quintest' cable tester by EBI communications.
I don't know a lot about this unit to be honest, it's been at the company longer than I have! Let me describe it, maybe you can shed some light...
It is basically two 'L' shaped units, almost identical which magnetically fit into each other, one is the 'remote unit'
Each unit has two sockets at the top, labelled '568A/B' and 'USOC'
(I always use the 568A/B socket)
Each unit has Bi-Coloured LEDs down the middle labelled with the pin pairs: 4-5, 3-6, 1-2, 7-8 under the 568A/B socket, with a final one at the bottom labelled 'Screen', which never comes on.
If a cable is OK, the LEDs on both units light up green in sequence from top to bottom, if there is a problem, one or more LEDs will either not light at all or light red.

The cable run on the site tests OK in the sense that when tested with the above tester, both units of the tester show the correct top-down green LED sequence.

Thanks again

Steve

 

[lopes1211]

Sounds like you have a basic continuity tester. It's showing you that all of the wires are terminated to the proper locations on each jack but it does not tell you if the cable passes cat-5 specs. You need a better tester to correctly verify the cable.

-CL

 

[Bobg1]

Are you sure about the nic settings on the pc?
Are they set up properly for the network?

 

[daronwilson]

Hmm, sounds like you have a management problem if you are trying to troubleshoot and fix this remotely. Not sure how to help you with that.

Your continuity checker won't let you know anything about interference, but a cable scanner capable of testing noise/attenuation/crosstalk/etc. on the line would provide you with that information. If you are getting a link light, I'm going to guess it's a configuration problem not a cable issue UNLESS it's very bad noise or attenuation.

Good Luck!

It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[OMaraSTO]

Thanks for the replies.

I know for sure that it is a cabling issue, not configuration. The computers used in our site offices are laptops, so can easily be moved around. Last time I was on site, I tried a couple of different laptops, in different locations. They both work fine on a connection in the office which has the wired hub in it, they also both work fine on a cable run i did to another office just opposite the office with the wired hub in it, they just won't work on the connection that runs past the wireless hub further down the hall (its not a length issue though, its only about 20 metres)

Also, a couple of you have said there that I need a better cable tester. As I may be doing similar installations in the future, I think I could probably get authorisation to spend a bit of money on one. Can any of you guys reccommend a good tester for cat5 installations???

Cheers

Steve

 

[Bobg1]

Is this cable just a long patch cord that you put together?
(stranded cable with plugs on the ends)
If so 20 meters is pretty long. A proper install would have solid conductor cable going from a patch point by the hub to a wall jack in th office space, where you would then use short patch cords on each end to make the final connections.

You also say you have tried conecting at other locations. Have you connected to the actual port you are trying to use this cable in? preferably with the notebook you want to use at the other end.

 

[OMaraSTO]

Yes, it is essentially just a long patch cable using stranded cable.
There are only three users on this hub, and the cabins don't actually belong to us (its a joint venture), so we can't do much in the way of installing wall sockets etc., this is really just a small-scale temporary patch job.

Having said that, I want the patch to run from the hub direct to the users desk, and not move about much, so would I be better to run the same type of 'patch cable' scenario but using solid cat5 instead of stranded??

I also considered only wiring in pins 1,2,3 and 6 to restrict the bandwidth to 10MBPS instead of 100MBPS, to cut down on interference, would this help??

(and yes, I have tried the same laptop in the same port on the hub it works ok, except when using the long cable)

Also still wanting reccommendations on a good cable tester??

Thanks very much for all your help

Steve

 

[Grenage]

I would imagine only wiring your pins would gain your nothing, if not hinder your connection.

My personal recommendation if you can gain access is to check all your settings and ports, and swap out of the cable you are using.

 

[lopes1211]

My vote is also for the "stranded" wire being the issue. Swap it out with some solid cat-5.

-CL

 

[Bobg1]

You can install a solid conductor cable and attach jacks at each end, they don't have to be mounted in the wall or a patch panel. Then use patch cords from the jacks to the hub and pc.