Table 9.10 - Near-end cross-talk (NEXT) loss for catedories 3,4 & 5 data cables,
| Table 9.10 - Near-end
cross-talk (NEXT) loss for ------------------ catedories 3,4 & 5 data cables, |
||
| Cable category |
Channel cross-talk(dB) |
Basic link cross-talk |
| Cat. 3 |
19.3
|
21.0
|
| Cat. 4 |
33.1
|
35.3
|
| Cat. 5 |
40.6
|
42.3
|
Attenuation is the loss in the data cables
and is measured in decibels (dB). The measurements taken for
Table 9.10 are made at 16 MHz with a cable temperature of
20oC. The temperature coefficient of resistance indicates
that copper cables increase in resistance as the temperature
rises. The last column of the Table shows the percentage rise
per oC above 20oC.
Table 9.11 - Attenuation
values for some data cables at 20oC, measured at 16 MHz
| Table 9.11 - Attenuation
values for some data cables at 20oC, ------------------ measured at 16 MHz |
|||
| Cable category | Channel attenuation |
Basic link attenuation |
Attenuation increase |
|
-
|
(dB/100m) |
(dB/100m) |
per °C (%) |
|
Cat. 3
|
14.9
|
13.2
|
1.5
|
|
Cat. 4
|
9.9
|
8.8
|
0.4
|
|
Cat. 5
|
9.2
|
8.2
|
0.4
|
The percentage loss from
input to output for a range of losses in decibels is given
in Table 9.13
|
Table 9.13 - Decibel loss expressed
as a ratio
|
|||
| Loss in dB |
V2 as a % of V1 | Loss in dB |
V2 as a % of V1 |
|
0
|
100 %
|
4.0
|
63 %
|
|
0.1
|
98.8 %
|
20.0
|
10 %
|
|
0.2
|
97.7 %
|
40.0
|
1 %
|
|
0.5
|
94.4 %
|
60.0
|
0.1 %
|
|
1.0
|
89.3 %
|
80.0
|
0.01 %
|
|
2.0
|
79.4 %
|
100.0
|
0.001 %
|
Extracted from The Electricians Guide Fifth Edition
by John Whitfield
Published by EPA Press Click Here to order your Copy.