Wireless warehouse

Hello.
We need to cover 256,100 sq. ft. warehouse by wireless network (multiple
rooms). Warehouse if filled by aisles tall almost to the roof. Basically
there is a lot of metal. At the beginning we was thinking about setting up
wireless AP with the same SSID running on different channels, each access
point would have connected two directional antennas through splitter so each
antenna points between two aisles. We already avoided this idea because in
case that we will need to move any of aisles we will need to move antennas
too. This is inconvenient.
My question is following: Does anyone has any ideas, experience, concerns
with this kind of project and would like to share them.

I appreciate all help.

Matthew Weiss
Network Communications
matthew(at)nj-computers.com
--

Maciej <maciej@nj-computers.us> hath wroth:

>Hello.
>We need to cover 256,100 sq. ft. warehouse by wireless network (multiple
>rooms). Warehouse if filled by aisles tall almost to the roof. Basically
>there is a lot of metal. At the beginning we was thinking about setting up
>wireless AP with the same SSID running on different channels, each access
>point would have connected two directional antennas through splitter so each
>antenna points between two aisles. We already avoided this idea because in
>case that we will need to move any of aisles we will need to move antennas
>too. This is inconvenient.
>My question is following: Does anyone has any ideas, experience, concerns
>with this kind of project and would like to share them.

Sure. However, I covered a few warehouse wireless horror stories in
past pontifications in this newsgroup. Using Google Groups search,
try:
| <http://groups.google.com/groups?as_q=warehouse&num=50&scoring=r&hl=en&as_ep q=&as_oq=&as_eq=&as_ugroup=alt.internet.wireless&a s_usubject=&as_uauthors=jeff+liebermann&lr=&as_drr b=q&as_qdr=&as_mind=1&as_minm=1&as_miny=1981&as_ma xd=5&as_maxm=11&as_maxy=2006&safe=off>

As for the splitter, that will work if you control the multipath.
Since a warehouse is the ultimate worst case indoor reflective
environment, and since the contents are always moving around, your
ability to control reflections will be very limited. I ended up with
one AP and one directional antenna per isle, but never tried using a
splitter or had to deal with moving isles.

500ft on a side. That's a big warehouse. It's probably too big to
use "leaky coax" along the roof line. How high is the roof or
ceiling? Is it flat or angled? Reflective, or absorbent? I've
always wanted to try bouncing a signal off a reflective roof and down
into the aisles. I sorta did that during a convention. I installed a
discone antenna near the metal roof line. The signal went out from
the antenna at slightly above horizontal, hit the roof, and bounced
down into the aisles. It worked fairly well, but wasn't up long
enough to determine if it was reliable.

--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On 11/5/06 1:37 PM, in article i3bsk2dk92n8vbatnb7ol69rj2rljhq65a@4ax.com,
"Jeff Liebermann" <jeffl@comix.santa-cruz.ca.us> wrote:


>
> Sure. However, I covered a few warehouse wireless horror stories in
> past pontifications in this newsgroup. Using Google Groups search,
> try:
> |
> <http://groups.google.com/groups?as_q...&hl=en&as_epq=
> &as_oq=&as_eq=&as_ugroup=alt.internet.wireless&as_ usubject=&as_uauthors=jeff+l
> iebermann&lr=&as_drrb=q&as_qdr=&as_mind=1&as_minm= 1&as_miny=1981&as_maxd=5&as_
> maxm=11&as_maxy=2006&safe=off>
>
> As for the splitter, that will work if you control the multipath.
> Since a warehouse is the ultimate worst case indoor reflective
> environment, and since the contents are always moving around, your
> ability to control reflections will be very limited. I ended up with
> one AP and one directional antenna per isle, but never tried using a
> splitter or had to deal with moving isles.
>
> 500ft on a side. That's a big warehouse. It's probably too big to
> use "leaky coax" along the roof line. How high is the roof or
> ceiling? Is it flat or angled? Reflective, or absorbent? I've
> always wanted to try bouncing a signal off a reflective roof and down
> into the aisles. I sorta did that during a convention. I installed a
> discone antenna near the metal roof line. The signal went out from
> the antenna at slightly above horizontal, hit the roof, and bounced
> down into the aisles. It worked fairly well, but wasn't up long
> enough to determine if it was reliable.

Roof is flat, reflective about 30 ft high and it has bunch of pipes and
other stuff right under. I was also thinking hooking up APs right under the
roof but I am really concerned about reflections.

Maciej <matthew@nj-computers.com> hath wroth:

>Roof is flat, reflective about 30 ft high and it has bunch of pipes and
>other stuff right under. I was also thinking hooking up APs right under the
>roof but I am really concerned about reflections.

My guess(tm) is that if you position the antennas parallel to the
ceiling, and at a distance where the reflected wave reinforces the
incident wave (1/4 wavelength), the problems caused by reflections
will be minimal. The basic problem still boils down to a line of
sight issue. However, the chances of maintaining line of sight to the
floor from the ceiling is fairly good if positioned over the aisles.
However, if as you say, the aisles tend to move, line of sight will be
a problem, especially if the merchandise is piled to the ceiling.

30ft range and 500ft long is far too long for leaky coax.

There's no perfect solution so you'll have to do the best you can with
whatever you can afford.

If you can position the antennas above the aisles, a horizontally
mounted sector antenna will have the optimum pattern. 120 degree
"vertical" radiation angle, which will go nicely down the aisle, and
perhaps 15 degree "horizontal" radiation angle, to keep the RF within
one aisle. 12-15dBi gain is more than adequate. With such antennas,
you can probably use power splitters as the likelyhood of a client
radio "seeing" two antennas is only possible up near the ceiling. On
the ground, they're isolated.

Something like these:
http://yu1aw.ba-karlsruhe.de/vhf_ant.htm
http://yu1aw.ba-karlsruhe.de/ANT.htm
http://www.brest-wireless.net/gallery/AntenneAmos
http://www.brest-wireless.net/wiki/materiel:amos
http://pe2er.nl/wifisector/
Look carefully at the antenna patterns.

Commercial version:
http://www.superpass.com/2400-2483M_120.html


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558