Les <hlhowell@xxxxxxxxxxx> wrote:
On Sun, 2007-02-04 at 11:07 -0700, David G. Miller wrote: Snip!
> Oh yeah. One other thing I do is my AP is in my basement. The basement
> walls are concrete with rebar so they do a good job of attenuating the
> WiFi signal. Makes it even harder to crack my network on a drive by but
> someone on my neighbor's roof would probably still get a decent signal.
>
> I always like the saying, "Locks keep an honest person honest." To this
> I add, "... or divert the dishonest person to look for someone with a
> weaker lock."
Hi, Dave,
Have you confirmed the signal condition from your basement? The WLAN
signal is very multipath capable, and the receivers for good systems can
pick it out of the mud with only about a 1db SNR. That is about 10
times as sensitive as most Ham Radios, and about 10000 times more
sensitive than most AM or FM table radios.
The technology is really amazing.
Regards,
Les H
Actually, it was experimentation while visiting my parents. Turns out
that one of their neighbors runs an open AP. I get a good signal to the
neighbor's AP when I'm on the main floor of my folk's place but an
unusable signal when I'm in their basement. I get the best signal when
I'm at the end of their house closest to this neighbor. This is with
concrete block foundations and wood frame houses. I don't know where
their neighbor has his AP. This also fits with my experience helping
some folks get wireless coverage everyplace they wanted it by moving
their AP around inside their house (bad AP location: bad coverage with
lots of dead spots; good AP location yields minimal dead spots but
probably accessible to "others").
I ran into this same effect at my last employer where some of the sales
engineers had set up a rogue AP. The steel frame of the office meant
that the AP was only accessible from certain locations on the floor we
occupied (e.g., not at all when the elevators were between the AP and
the person attempting to connect). I also vaguely remember reading an
article on suggestions for EM hardening to take advantage of this for
securing wireless. I put my experience with the neighbor's wireless
together with the strategy described in the article on EM hardening and
came up with putting my AP in my basement should make the signal fairly
unusable off of my property.
The radio signal used by wireless does a good job of penetrating wood,
drywall and most home building materials (no multipath involved). It
doesn't do as well with steel, wiring or *enough* earth. This is
especially true when the steel forms a "cage" as is the case of rebar in
a poured foundation.
Cheers,
Dave
--
Politics, n. Strife of interests masquerading as a contest of principles.
-- Ambrose Bierce
