Why the 100m CAT5 cable length limit, signal strength or timing? and does the length include hubs/switches?

Question

I have a CAT 5 cable that should be under the 100m/300ft length limit but not getting good/any performance. Cable tester shows working for straight-through connection. Can sometimes load a webpage but usually not.

If length limit is based on signal strength, then shaving off a few feet won't matter, but if based on timing, a few feet can make a big difference.

Connection is this: modem to wireless router feeding signal to one building, then cable from this router to a switch in a second building about 75' away, then cable from switch to second wireless router in another building about 200-300 feet away.

a) timing or signal strength driving length limit?

b) is the max length from modem to last computer, or from one "box" to the next?

c) could the switch be causing me grief, and why?

Alternatives welcome, however this is a home system so cost is a major factor.

Thanks

Answer 1

a)  Technically speaking, it's the resistance in the copper of the cable that's limiting the distance.

b) The length is from one computer to another, or from a switch or a hub to a computer.  If it was the physical distance between two computers, you and I couldn't have this conversation :)

c) No, the switch isn't causing the problem, it's the cable distance.  Just put another switch halfway along the cable length and you should be fine.

MLindahl

Answer 2

when i bought my 100' ethernet cable to hook my laptop

to the internet i was told that the cable shouldn't be over 300'

personally i would try to go wireless as much as possible.

matbe somebody with more knowledge than me can help

you better.sorry best i can do.

Answer 3

Actually it is a little of both, the signal will degrade to the point the equipment can't tell the 1s from the 0s anymore and it will appear as a steady current. (simplified answer)

And it is between any 2 devices, so final switch to PC is the only length you need to worry about.

If you are well under 300' I would look for the following.

-Bad Cable, ends not crimped correctly fully, cable damaged

- Are ends in the correct order for pairing? Pairs are 1&2,3&6,4&5,7&8

-Bad Switch or Switch port

-Does the cable run near any fluorescent lamps or run parallel to electrical lines in the home

Also what kind of cable tester do you have? the cheaper ones (under $100) only check basic continuity and correct wirring on both ends. A higher grade model will check cable pairing (very important) and for interference. Pairing is very important to stop crosstalk.