DWL-900AP+, 5v Power over Cat5, Slotted waveguide.

Lyle Williams lyle.williams at bigpond.com
Fri Dec 27 07:52:08 EST 2002

I only have enough Cat5 to get up the mast here, and I'm using pairs of
conductors for power and ground.  At present, things seem to be working, but
I haven't really gone through any temperature extremes, nor had anything

I have built some 5v power supplies for mobile AP testing using 7805
regulators and 2955 power transistors, but they really do produce a
tremendous amount of heat.  I'd like to keep that heat out of the box.  I
guess I could rivet the regulator/transistor to the back of the waveguide
(call that a heatsink?  THIS is a heatsink!), but I was trying to keep
things neat.

Lyle Williams

----- Original Message -----
From: "Alastair D'Silva" <deece at newmillennium.net.au>
To: "'Lyle Williams'" <lyle.williams at bigpond.com>;
<wireless at lists.samba.org>
Sent: Thursday, December 26, 2002 9:58 PM
Subject: RE: DWL-900AP+, 5v Power over Cat5, Slotted waveguide.

> Hi Lyle,
> Looks pretty funky! One thing you'll with running 5V POE to the unit is
> that once you start adding a bit of distance on the cat5, you'll have a
> significant voltage drop. At MonashHub, we were getting about 3.5V at
> the AP, waaaay too low to make it function.
> I ended up making up some 5V switchmode regulators (thanks to
> Maxim-ic.com for the schematic and sample controllers), which fit within
> a 1" diameter piece of heatshrink, and powers the AP fine. We're using
> them on 2 900AP+ and a 1000AP, with no problems.
> We drive the Aps with modified realtek NICs, with molex connectors added
> to feed +12V down the line.
> Since you've offered to provide one of your waveguides to the Canberra
> Freenet, I'd be happy to make up a couple for your use. If anyone else
> wants one, email me or check back on http://canberra.freenet.in-a.us
> (I'll update the site when I get back to Canberra on the 4th).
> --
> Alastair D'Silva   mob: 0413 485 733
> Networking Consultant
> http://www.newmillennium.net.au
> > -----Original Message-----
> > From: wireless-admin at lists.samba.org
> > [mailto:wireless-admin at lists.samba.org] On Behalf Of Lyle Williams
> > Sent: Thursday, 26 December 2002 6:01 PM
> > To: wireless at lists.samba.org
> > Subject: DWL-900AP+, 5v Power over Cat5, Slotted waveguide.
> >
> >
> >
> > I've finished weatherproofing a DWL-900AP+, and it has been
> > mounted on the side of a 8-slot waveguide.  Power (5v) is
> > supplied over unused pairs on the Cat5 ethernet cable.
> >
> > A picture (~200kB) is at http://www.qsl.net/vk1xlw/DSCF2198.JPG .
> >
> > Currently I'm testing with the waveguide 2m off the ground.
> > If things continue to go well (after a really hot day...),
> > I'll pull my mast down and mount the waveguide at about 6-7 m.
> >
> > Lyle Williams
> > VK1XLW
> > 26DEC02
> >
> >
> >
> >

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