DWL-900AP+ External Mounting

[Jim Carter]

On Mon, 24 Mar 2003, Akash Heimlich wrote:
> got myself 3 DWL-900AP+ (firmware 2.5) units.  Since it get rather hot
> in India, I decided to house the units in a large PVC pipe.

I have the vision of a PVC cylinder open at both ends, with maybe an
umbrella on top -- or the solar panel -- and the aluminum plate vertical on
a diameter, so air can flow freely up and down.  Anything in thermal
contact with the plate, like the LM317 regulator, would stay fairly cool.
However, there is essentially no thermal contact between the DWL-900AP+
processor and PCMCIA card and the plate, so the plate would just act to
support the AP while letting air circulate, not to cool it.

Be careful that a bird or wasps don't make a nest in your AP.  Screens
across the ends would help.  Also beware of high winds; the solar panel and
upper sunshade need to be mounted strongly.

> I then wrapped
> the entire tube in silver foil to protect it from the heat.

Real silver foil?  That's hard to get, at least where I live.  Aluminum
foil has to be replaced periodically due to corrosion, but cost is no
issue, only the labor of retrieving your device once or twice a year.

> Second, sometimes the speed would drop to 1 MBit due to something or
> other.  ...  I am
> wondering if this could have anything to do with the aluminium plate the
> ap is tied to?

With an omni antenna well away from the plate and the foil, there should be
no problem.  It would be another story if you were using the internal
antenna :-)

> And third and wierdest, every day between 10 am and 1:05 pm, the unit
> connected to the solar panel/battery resets randomly every 30 seconds or
> 1 minute.  ...  Any ideas?

We had AP's lock up on us with firmware 2.2 and 2.3, but we haven't seen
the behavior you describe with firmware 2.5.  One colleague says he
uploaded over 1 GB of data successfully, while another (with better signal
strength) says that (with his partner card) he can't keep up a reliable
connection.  This is to the same AP.  Firmware 2.56 is on the web site, and
upgrading it is on our "to do" list.

James F. Carter          Voice 310 825 2897    FAX 310 206 6673
UCLA-Mathnet;  6115 MSA; 405 Hilgard Ave.; Los Angeles, CA, USA  90095-1555
Email: jimc at math.ucla.edu    http://www.math.ucla.edu/~jimc (q.v. for PGP key)