[MLB-WIRELESS] Waterproof casing advice...

[Ratbaggy]

Hi,

A $15.00 box is cheaper than a wet Minitar that's eaten itself.

Will and I have used a couple of the Jaycar boxes on our links and found
them just about perfect for the job.  The mounting holes in the base are
isolated from the sealed section via voids to the top of the box.  We used
these to mount via standoffs to an aluminium plate with slots to accommodate
hose clamps to the mast.

Teamed up with the Jaycar glands for cat-5 and antenna cables on the bottom
side we have had no ingress of moisture at all.  If you wanted to use the
smallest box (cheaper) that fits the minitar, you could poke the antenna out
through a gland.

If you extend the aluminium plate past the box so as it sits behind the
antenna it will act as a reflector and give you a bit of directionality and
an extra 3 dB of antenna gain.  Ideally the antenna should be about 3-4 cm
away from a plane reflector.

BTW it is easy to mod a Minitar for POE, just cut the two tracks that run to
the terminating resistors for the unused cat-5 pairs.  Then run a wire at
the back of the Ethernet connector from each of the unused pairs to the
power inlet connector.  Make sure you get the polarity right!

David Nuttall.


----- Original Message -----
From: "Donovan Baarda" <abo at minkirri.apana.org.au>
To: <melbwireless at wireless.org.au>
Sent: Tuesday, June 08, 2004 10:03 AM
Subject: [MLB-WIRELESS] Waterproof casing advice...


> G'day,
>
> In the process of getting together all the gear to connect to another
> site about 50~100m away. I have minitar AP's, cable glands, POE stuff
> etc. The only things I'm missing is a waterproof box to put the minitars
> in, and a pole and mounting bits and pieces.
>
> As the distance is so small, I wanted to try using the standard little
> minitar omnis instead of some sort of additional aerial. This way I can
> put the minitar+aerial in a sealed plastic box, with only the cat5 with
> POE going into it via a single gland.
>
> I had a look at the Jay-car boxes. There are two boxes that could fit
> the minitar+aerial (on an awkward angle, but the larger sizes were too
> big). They both have nice rubber seals, and the only difference appears
> to be different plastics (one grey, the other white, with different
> plastic TLA's). They are $15+ each, which seems kinda pricey for a
> plastic box.
>
> I was thinking a $2 tupperware container sealed with silicon and mounted
> on a pole with large cable ties should be good enough for the job.
> However, I have a few concerns;
>
> 1) will tupperware plastic perish badly under UV exposure. Will a coat
> of white spray paint help? Will some paints interfere with the RF?
>
> 2) most tupperware seems to use clear thermoplastic. Will the light
> going through the tupperware heat and/or UV degrade the AP itself? Will
> a coat of white spray paint help? Should a choose a non-clear tupperware
> container?
>
> 3) Are cable-ties a bad idea for pole-mounting? I have a heap of very
> big cable ties (50cm long, 1~2cm wide) that I have used outdoors before,
> and they seemed to degrade a bit, but only broke under repeated flexing.
> I _think_ they would be OK for this application, but welcome feedback.
>
> 4) I want to mount it on the existing TV aerial pole. Ideally I would
> attach it to the pole just below or above the TV aerial. Would this
> interfere with the TV? I could try attaching an extension pole to the TV
> aerial pole; any hint's on the best way to do this? What about
> lightning?
>
> The best sized case I've found is a black-plastic VHS video container.
> However, I don't know how the black plastic would handle UV, and it
> would probably be trickier to silicon seal than a tupperware container.
> Anyone tried using one of these?
>
> Basically, what is a decent budget RF transparent case that would fit a
> minitar+aerial, and what's the best way to mount the sucker up a pole.
>
> --
> Donovan Baarda <abo at minkirri.apana.org.au>
> http://minkirri.apana.org.au/~abo/
>
>
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>


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