[lug] Wireless router question (OT)

[Stephen Queen]

On Wed, 27 Oct 2004, Daniel Webb wrote:

> On Wed, Oct 27, 2004 at 09:12:34AM -0600, Warren Sanders wrote:
>
> Your post reminded me of something I've been wanting to ask on this list in an
> off-topic thread: given that all the consumer 802.11b gear is either so-so or
> total garbage, are there pro-quality brands that sell consistently good gear?
> If so, how much is the price difference?  Do any of you have experience with
> 802.11 gear that doesn't suck?  I want the wireless networking equivalent of a
> HP Laserjet 4 printer.
>

We installed 3 wireless AP's on our Newmont Time Domain
Eletromagnetic data collection system (NEWTEM). This
instrument had some rarely encountered problems because it
is made of 3 nodes. One node, the controller resides inside
the cabin of a helicopter ( usually a Lama ). The second
node, the receiver is suspended approx. 30 m below the
helicopter, and the 3rd node, the transmitter is suspended
30 m below that. This arrangement causes the antenna
coupling to be constantly changing.

The operating systems on all 3 nodes is linux of course. The
RX and TX are network boot, so that the root file systems
for both reside on the controller inside the helicopter. A
hard disk would never survive all the take offs and
landings.

We started with 3 units from Lincsys. Even while testing on
the ground it was difficult to maintane consistant
communication. But on take off, we lost newtork connection
long enough for either node 2 or node 3 or both to crash
around 2 out of 3 times. With the price of helicopter time,
this was unacceptable.

We then bought some AP's from a company that makes PLA's .
The company name is Data-Linc. The model number was FLC810E.
We started with their 8dbi omni directional antennas. For
those who are reading this who don't know, an antenna like
this boost its power rating by focussing the power in a more
concentrated pattern. In other words it is not truely
omni directional. The radiation pattern can be viewed as a
doughnut. The higher the power rating, the flatter the
doughnut. We oriented the antennas into a horizontal plane
so that most of the energy was radiated vertically. In our
testing, we only had 2 drop outs, and both of those occured
on landing. We attributed the drop outs to pour coupling as
the antennas ended up pointed right at each other. It also
could have occured because of static discharge, as the
instruments touched the ground. ( There is a high static
charge built up from the prop wash.)

To resolve these drop out problems we have purchased the
6dbi antennas, but as of yet have not flown with them, so I
cannot comment on them. I can say the industrial strength
FLC810E's were far superior to their SOHO counter parts. But
the purchase price was $995.00. The antennas were
additional. They do come with a small dipole though.

Steve