# How are weak signals possible?

Member Posts: 105 ■■□□□□□□□□
Hi

A repeater basically sends a copy of a signal to where the signal has to go right. It makes the signal stronger. Now firstly how can a signal become weak? Isnt it just ones and zeroes? What is meant by a signal becoming a weak?

Secondly I am sure the Ohm's law of resistance applies to cables. So do networkers actually study physics and stuff to try and reduce resistance or whatever? Do they use transformers to increase the voltage and so decrease resistance?

Embarrassingly dumb questions.

• Member Posts: 4,884 ■■■□□□□□□□
Now firstly how can a signal become weak? Isnt it just ones and zeroes? What is meant by a signal becoming a weak?

It's called "attenuation". The signal is ones and zeros, but they are represented by electrical impulses. Electricity is subject to degradation over long distances.
Secondly I am sure the Ohm's law of resistance applies to cables. So do networkers actually study physics and stuff to try and reduce resistance or whatever?

Networkers just familiarize themselves with the standards for things like CAT5 being 100 meters, and the different distances allowed on certain fiber cables, etc. Just whatever you happen to be using. It's the design engineers of the manufacturers that go deeper into it.
All things are possible, only believe.
• Member Posts: 2,111 ■■■■□□□□□□
Hi

A repeater basically sends a copy of a signal to where the signal has to go right. It makes the signal stronger. Now firstly how can a signal become weak? Isnt it just ones and zeroes? What is meant by a signal becoming a weak?

Secondly I am sure the Ohm's law of resistance applies to cables. So do networkers actually study physics and stuff to try and reduce resistance or whatever? Do they use transformers to increase the voltage and so decrease resistance?

Embarrassingly dumb questions.

You should read up about the electrical characteristics of th different cable types, ITU-T is a good start.When you say a signal is just one's and zero's , do you know how a one and a zero are actaully represented? Its not as simple as a high and low voltage,its a waveform, and there are strict amplitudes defined to distinguish between a one and a zero.So as current flows through the cable it gets weaker due to heat loss, and it gets distorted due to external electromagnetic fields.So all these external forces play a part in modifying the waveform and hence make the signal weaker.
Networking, sometimes i love it, mostly i hate it.Its all about the \$\$\$\$
• Member Posts: 1,218
how can a signal become weak? Isnt it just ones and zeroes? What is meant by a signal becoming a weak?

Sprkymrk hit it. It has to be converted to an electrical signal before it can be sent over the wire. You cant put a visual or tangible graphic representation into a data cable.

As far as it being weak, think of your voice. If you talk to someone in the same room, they can hear you fine. If you tried to talk to someone accross town, your sound waves would not be strong enough to get there.
• Member Posts: 105 ■■□□□□□□□□
oh ok I get it now Thanks for clarifying that.