Archived from groups: alt.internet.wireless (
More info?)
Leaky Coax works well with 11b, and actually better with 11g as OFDM is more
forgiving. Multi-path has not been an issue with our installs as we only
run 1 radiator in
an area... Even with multiple radiators, each antenna is only x-mitting and
rcving at the same
instance (TDD) as it is hooked to the same Radio..
Multi-Path from the perspective of the client has not happened... I can only
guess why..
perhaps because the area from the cable that is in the radiation zone is
small, low DB after
a reflection and phase shift, the difference in gain is great hence no
problem???
We have actually loaded Radio's farther
down the line with Duplexors made by Motorola (but I am not sure how they
take care
of issues.. already a done design) This was done on a Metal Vessel..
3 Radios per cable... 1,6,11
The only problem with the design of these systems and 802.11 is CSMA...
Hidden node
can become an issue for obvious reasons.. so RTS/CTS helps... I have found
great results
in limited clients, and good results for internet access which can take
collision reduced bandwidth
with higher number of users...
For a lower loss for 2.4Ghz but a super high price, there is Leaky
Waveguide... but will suffer
the same problems.
The stuff is just to expensive for me to experiment with for
more qualified data
"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote in message
news:ftemr0tkhfpsuqishq288qoc7n1ob360kf@4ax.com...
> On Sat, 11 Dec 2004 09:16:36 GMT, "Fresnel Fadermargini"
> <RSSI@pathloss.dbm.com> wrote:
>
> >Actually "Leaky Coax" is available for 2.4Ghz, but it is quite costly..
> >I have worked with many different distributed antenna systems for 2.4..
> >Many Installers of Malls, Hotels, Train Tunnels, i.e. Sprint etc.. use
DAS
> >instead of gobs of AP's...
> >
> >Andrew makes a great one for 2.4 that I have used in a tunnel in Europe..
> >It is a combination of their RADIAX and HELIAX cables:
> >
http://www.andrew.com/search/docviewer.aspx?docid=3892
> >
> >Very cool stuff that works, but probably way way too costly for your
home..
> >Besides 5/8" hardline is not easy to pull anyway
>
> Does it work with 802.11b/g? When I tried some lab experiments with
> multiple antennas on a coax run, I found that multipath was just
> killing the data with delay spreading and generating intersymbol
> interference. I got great signal signal strength, thruput just stunk.
>
> We didn't use leaky coax as we didn't want to lose signal by radiating
> inside walls, risers, ducts, etc. The system was a number of fairly
> high impedance radiators, located on multiples of a half wave
> electrical along the coax. The end was terminated to eliminate
> reflections. The match was tolerable (-15dB return loss) mostly
> thanks to cable loss. A typical large room had 4 radiators.
>
> It worked well if I had only one radiator per room, but would screwup
> badly with 4 due to multipath. I never tried leaky coax because I
> assumed it would have the same problem. However, this was before
> 802.11g, where OFDM may have helped deal with the reflections.
>
> Duz leaky coax work with 802.11b/g?
>
>
> --
> Jeff Liebermann jeffl@comix.santa-cruz.ca.us
> 150 Felker St #D
http://www.LearnByDestroying.com
> Santa Cruz CA 95060 AE6KS 831-336-2558