[MLB-WIRELESS] Wireless Network Project

Ratbaggy wireless at smithsgully.net
Fri Jan 16 11:12:39 EST 2009


Hi Steve,

I may have a solution for you using Jason's Minitar contact.

Three years ago, I helped a mate set up a sytem in an identical scenario 
to get some internet up to his parents place 500 m away.  We used the 
old Minitar 11B devices mounted in Jaycar sealed polycarbonate 
enclosures (HB6218 etc.).  The great thing with this setup is you drill 
a hole in the box, mount a gland (Jaycar HP0732 etc.) and poke the 
unit's own antenna down through the gland to be used as the driven 
element in a trough reflector.  Another smaller gland is used for the 
cat5 cable (Jaycar HP0724 etc.)

There is some cutting and 2 bends of a sheet of aluminium which mounts 
on the back of the box to form the trough reflector.  We used a TV mast 
bracket sandwiching the aluminium plate on the back of the box to 
support the aluminium reflector and mount the box to the TV hockey 
stick.  (Brackets from Alvin electronics "FWM" flush wall mount, on this 
page FWM 
<http://www.alvin.com.au/index.cfm?siteaction=catalog&mcat=10&cat=47&sr=21>. 
Bitek in West Heidelberg also have similar brackets)

This setup yields about 8 dB of gain at each end of your link WITHOUT 
buying an antenna or any pigtails or any losses associated with 
connectors or feeders.

We cut the DC plug and a few cm of cable off the power pack and used the 
spare pairs in the cat5 cable to power the unit.  The old Minitars had 
an internal switchmode power supply which tolerated quite a wide input 
range so the DC losses in our 10 m run of cat5 weren't a problem.  You 
may well get away with it with the new units too, I see they run off 9 
Volts.

The costs:
2 AP's @ $35 = $70
2 Boxes @ $17 = $34
2 FWM's @ $7 = $14
Bag small Glands @ $5
Bag larger Glands @ $5
Scrap Aluminium sheet $ 0
Assorted Hardware

Total Cost  $128....   Way under budget!

If you want to give the design a try I can go take some pictures of the 
units (which are still in situ and working after 3 years!) and supply 
you with the dimensions of the aluminium sheet.

Regards

Dave

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