WiFi Problem

James Cameron quozl at laptop.org
Tue May 13 18:24:38 EDT 2014

On Tue, May 13, 2014 at 09:28:31AM -0500, Juan Carlos Garcés Mariño wrote:
>   (dBm)                 rssi           snr          nf
> Bad laptop               -85           13          -98
> Good laptop              -40           53          -91

The RSSI is much lower than usual, the noise floor is a bit lower than
usual, as a consequence the signal to noise ratio is too low for
reliable operation.

There is a major fault in the radio system of this bad laptop.

I do not recall what you have tried so far, but my advice is to change
the system a component at a time to find out which component is at
fault.  There are only three components that can be changed;

- change the left-hand antenna and coax,

- change the right-hand antenna and coax,

- change wireless card.

Test again after each change.  Record the results.  Identify the
faulty component and replace it.

Predictable causes of failure for each component:

- antenna physical impact damage,

- water in antenna case,

- broken coax cable termination inside antenna,

- coax cable twist, compression, abrasion or water damage,

- coax cable connector physical damage,

- wireless card connector physical damage,

- wireless card electrostatic discharge damage,

- wireless card water damage,

- wireless card product lifetime or thermal cycle damage.

James Cameron

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