How do you compute for cable loss?
- Thread starter kiwi00
- Start date
Phone cable is not coax being operated at RF, so that calculator does not apply.
To do a calculation of losses, start by studying the specifications for Cat3 cable.
Pay attention to the Resistance per 100m, and the Capacitance per foot.
What frequency/pulse shape/amplitude is your signalling?
What is the source impedance?
What is the load impedance?
How accurately do you need to know the signal shape/amplitude at the receiving end?
Great for COAX. For twisted pair -- not so much.
The calculator let's you select from a variety of different cable types, including the RJ11 the OP asked about.
However, we don't have the background information to understand exactly how the calculator works, so if it's wrong, we'd need to do some hand calculations to show it. Anyone have some good formulas for RJ11?
However, we don't have the background information to understand exactly how the calculator works, so if it's wrong, we'd need to do some hand calculations to show it. Anyone have some good formulas for RJ11?
Just to be clear RJ11 refers to the connector, NOT the cable. The cable is usually dual twisted pair and I didn't see that alternative in the calculator, but maybe I missed something.
The following slides may be of interest to you
https://www.ceid.upatras.gr/webpages/faculty/alexiou/ahts/other_pdf/4_Twisted_p.pdf
The following slides may be of interest to you
https://www.ceid.upatras.gr/webpages/faculty/alexiou/ahts/other_pdf/4_Twisted_p.pdf
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True. I assumed the OP was referring to typical phone cable. The calculator has a selection for RJ11, and again I assumed that it was for typical phone cable.
@sailorjoe : RG-11 coax cable (Belden 8213 or 8261) has nothing in common with Cat3 phone cable, except that they might both have some Copper in them...
Yeah, Mike, I know. OK, my bad. I went back and checked the calculator, and I apparently misread the RG-11 entry as RJ-11.
Perhaps the OP can get some insight from this article, plus the one in post #6.
http://www.scatmag.com/technical/techarticle_dec02.pdf
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