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SCAN-LAN VI
8.2.3 A
TTENUATION
The Attenuation test measures the reduction in the strength or amplitude
of a signal as it travels over the length of a twisted-pair cable. The amount
of this loss is expressed in decibels (dB) (refer to Figure 8-9).
Figure 8-9. Attenuation.
Attenuation varies with frequency and length. Typically, attenuation
increases with higher frequencies and longer cables.
The table below lists some common causes of attenuation and possible
solutions.
Common Causes of
Solutions
Attenuation
Incorrect grade cable
Be sure to use the correct grade of cable for the
for application
specification being tested. Lower-grade cable can cause
greater attenuation.
Patch cables
Patch cables may not be twisted pair. A common mistake
is to use untwisted telephone wire for data applications.
Make sure patch cable is data grade.
Excessive Length
If specification is based on a maximum length, check length
and correct if necessary.
Poor termination
Check all terminations for proper connections. Follow
troubleshooting tips in “
Common Problems for Attenuation
.”
(Sending unit)
(Receiving unit)
Summary of Contents for SCAN-LAN VI
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