[plug] OT: Point to multipoint wireless

[Onno Benschop]

On Fri, 2004-03-12 at 15:36, Kai Jones wrote:
> Ben Jensz wrote:
> > Ventilated = letting the elements in though :)  Especially when we get 
> > that horizontal rain during parts of the year.  If a product located 
> > outside can tolerate the weather conditions we get here during certain 
> > times of the year... its doing pretty well.  I'd personally suggest that 
> > when you purchase this equipment, make sure you factor in spares.  If 
> > you go for 900+ APs, then keep a spare on standby in case one gets blown 
> > up or even blown away :)
> 
> Yahuh, sorta catch 22 but what I'm thinking is to have a bottom-less box 
> with no vents on the side or top, but have the AP sitting on a grill 
> kinda thing so, even though there's no air coming in from around the 
> box, a bit of suction happening from atmospheric pressure differences 
> and blah blah, should get enough breeze in there to keep everything happy.

As you (may or may not) know I'm travelling around Australia with a
satellite dish in the back of my van. I have attached to the dish a
modem, a tuner, several power supplies and a ups. Cooling was a large
consideration for me.

Initially I used a design that was open. There was a fan blowing air
through the system and it cooled well. Except that in the humidity it
also rusted - lots - to the point where I had to replace a circuit
board. (I did investigate water-proofing, long story - for another day.)

My dish (the modem actually) is connected to the world via two DLink
900AP+, which are both connected to a hub and the hub is connected to
the modem. This setup allows me to have a node around the dish and a
wireless bridge with a high-gain yagi pointing somewhere else.

Now, I can finally get to the point I'm making...

The two AP's and the hub are stripped to their circuit boards and bolted
into a waterproof box - IP whatever the highest rating is - waterproof.

The box is in turn bolted to a mast and sits there most of it's days
(except when I'm transporting it to the next destination).

The setup has been across the state, has worked in full sun on a 46
degree day and never missed a beat. There is no rust, no corrosion of
any kind, and the thing never sleeps.

It is *very* unlikely that the electronics of an AP will get anywhere
near the 85 degrees that *might* stop the electronics from working. The
likely hood that if it ever got that hot, it would not actually stop,
but reduce the life-span of the device.

My point is this:

Heat is not your problem. I have set this up in Kununurra, Darwin and in
the middle of Australia with absolutely no problems.

Water is your problem.

So, my advice, get a waterproof box, bolt the thing inside and forget
about it.

Hint: Make sure you can remove the lid so you can press the reset button
if you stuff up the installing of new firmware or configure it to use
DHCP to get an IP address you cannot get to... (or write down the MAC
address before you seal the box)


> A very sturdy mount should hopefully stop it having any hassles during 
> cyclones and unexpected squalls, then again, if a cyclone's coming we 
> could just un-mount it just after yellow alert has been issued and put 
> it up whe the cyclones gone.

If the building is still there...


> If I decide to go with the 900+ AP's I'll factor in two and give reasons 
> and see if the councillors understand the logic.

You will need one for each location, so we're talking three plus one
(that or, you can use a PC as a client, but that is not my
recommendation).

You also need to factor in that 802.11 doesn't like travelling up and
down so much (depending on the antenna), so mounting them all at the
same height is a good idea.

You also can just start with three, put them on top of a shelf in the
tree buildings - if they don't have too many walls between them and the
angle of the signal through the wall isn't too acute (straight through a
wall is *much* better than at an angle - imagine the wall looking 10
times as thick on an angle)

But then again, "What do I know?", I just build it and use it, so you
can ignore anything I said.



Onno Benschop 

Connected via Optus B3 at S41°18'23" - E146°49'07" (Holwell, Tas)
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