[MLB-WIRELESS] Waterproof casing advice...

[Donovan Baarda]

G'day again,

minkirri is getting closer to being online, and hooked up to urania.

From: "Donovan Baarda" <abo at minkirri.apana.org.au>
[...]
> From: "Ratbaggy" <notme at iprimus.com.au>
> [...]
> > 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.
>
> I'm not an RF man, but I'm sufficiently fussy that "about 3 or 4 cm"
doesn't
> sound acurate enough.
>
> I found this corner reflector design;
>
> http://www.freeantennas.com/projects/Ez-10/
>
> It uses a full 90degree corner, not the "about 6cm flat with ends bent in
at
> 45 degrees". Any comments on what is better?

In the end I went with ratbaggy's advice and made the 6cm with two 45 degree
bends, rather than the single 90 degree corner... it was easier to make.
After agonising over the dimensions, and comparing the dimentions of the two
designs. I had to admit I had no idea what I was doing. I went with a 6cm
"flat back", two 8cm 45 degree "flanges", and put the omni 3cm from the
"flat back". This makes it almost identical to the above 90 degree design,
except with the 90 degree corner cut off. There were subtle differences in
the dimentions ratbaggy gave and the above design. With no better clues
about aerial design, I just went with a "close enough for rock and roll"
attitude.

> > 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!
>
> I'm taking pictures with my blurry-cam, for what they are worth. I will
wiki
> what I've got at the end of it all.

I've been collecting pictures, and have whacked them up on my system for
now. When I get everything together, I'll clean it all up and probably put
it on more widely used wiki, with detailed dimentions and instructions.

http://minkirri.apana.org.au/Wiki/WirelessHowTo


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Donovan Baarda                http://minkirri.apana.org.au/~abo/
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