[MLB-WIRELESS] Waterproof casing advice...

[Ratbaggy]

Unless there is an obstacle quite close to your antenna, the difference in
height with inverted or non inverted placement will make very little
difference.  As Dan said, the radiation pattern should be the same either
way.  Hence it comes down to water ingress and the most likely candidate
would be around the gland, so my vote would be for an antenna pointing down.

If you wanted to take this one step further, you could make a couple of cuts
in the plate along the edge of the box from the outsides towards the centre
leaving about 6 cm in the middle and bend the 2 sides forward on a 45 degree
angle.  This would form a 90 degree corner reflector antenna and if you
started with a 20 cm wide plate, this would give you up to 10 dB gain.
Maybe overkill for a 100 m link but something like that should be good for a
km or so under LOS conditions.

Yes, if it works out, publish it on the wiki.  I doubt I'll get around to
experimenting with short range stuff where I live.  Oops, there is that last
300m from the ridge to here....  Let my know how you get on!

David Nuttall.


----- Original Message -----
From: "Dan Flett" <conhoolio at hotmail.com>
To: "'Melbourne Wireless'" <melbwireless at wireless.org.au>
Sent: Wednesday, June 09, 2004 2:58 PM
Subject: RE: [MLB-WIRELESS] Waterproof casing advice...


> > > Good idea... I didn't think of that. How would the little minitar
> omni
> > > hold up against the weather?  Should I put it in heatshrink? Is it
> OK
> > > for the aerial to point down, reducing the chance of water getting
> in,
> > > or does it need to point up?
> >
> > The Minitar omni is about 2dB gain - that means it radiates pretty
> well
> > in almost every direction except straight up and straight down.  You'd
> > be pretty safe to use it upside down I think.  Glue heatshrink will do
> a
> > pretty good job of keeping the water out - it's not really watertight
> > and I imagine water would get in and corrode the radiating elements
> > inside the plastic.
>
> Just thought I'd correct my own poor grammar here: The glue heatshrink
> *is*  quite waterproof, the Minitar omni antenna is not really
> waterproof.
>
> Dan
>
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