[Soekris] Soekris 5501 with Many Errors Using Metrix miniPCI 802.11

[gavrik peterson]

Nice images illustrating your shielding fix.

It appears that you are using the U.FL to RP-TNC pigtail that Metrix
supplies. While it's coaxial cable is small in diameter this does not
mean that it is not effectively shielded. The thickness of the outer
conductor does not matter at 2.4GHz because the skin effect causes
current to only penetrate a small distance into conductors. Because of
this the cables return current flows in a very thin layer on the
inside surface of the outer conductor -- much thinner then the outer
conductor itself. At these frequencies most of the copper in a coaxial
cable is wasted as current only flow as thin "surface" currents.

Have you tried testing with the hard drive connected but located far
from the CM9?

  --  Gavrik


On Jan 14, 2008 2:45 AM, Randy Bush <randy at psg.com> wrote:
> For our Tokyo apartment border device, I hacked together a Soekris 5501
> with a large SATA hard drive, a Metrix CM9 802.11abg miniPCI card, and
> FreeBSD 8-CURRENT. All worked well except the wireless was significantly
> damaged due to very very frequent errors causing TCP back-off. It was
> pretty useless. I spent a number of hours chasing it down, some with the
> help of the FreeBSD Net mailing list and Sam Leffer in particular.
>
> I attempted to better shield it.  A full description with pretty
> pictures is at <http://rip.psg.com/~randy/5501-abg.html>.
>
> Bottom line so far: hokey household supply shielding has not fixed the
> problem.  I suspect the hard drive mounting over the miniPCI may be the
> problem, but really do not know.
>
> Help/clue still needed.
>
> randy
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