[Cu-wireless] status report; weekend meeting?
by way of Illustrious niteshad <niteshad at whopper.de>
niteshad at whopper.de
Thu Oct 31 14:24:19 CST 2002
A few more options exist for solving the "long haul" problem of connecting
Peter Miller's house to the IMC. Some of them are social in nature while
others are hardware/physical in nature.
The first social fix that comes to mind is collecting a list/database of
people who would be willing to join the network, either now or at some point
in the future. We seem to enjoy a tremendous amount of support from the
local community; at least I can't really recall anyone who thought that what we
were doing was a Bad Thing...OK, maybe the Ham radio people. At any rate,
if we emphasize that our network is currently somewhere between Alpha and
Beta Test, I think that we still could find people who would be willing to
join the network, even at this phase.
If the _CU-Cityview_ is doing a story/feature on us, one way to find out
how many people are interested would be to put some kind of interactive form
on our website where people could "pre-register" as nodesites. The article
would give us exposure in the community, the website would allow us to start
planning potentially tens or hundreds of nodes. Some of these nodes may be
in the area of PM and the IMC.
An alternate solution might be to steal an idea from Peter and war drive
Urbana, then send a targetted direct mail campaign to those who already have
an interest in wireless networking.
If the IMC's transmitter is "reticent" due to interference from other
local WLANs, perhaps we could, in a neighborly sort of way, contact the owners
of those WLANs and ask that we coordinate our channel allocations. This is a
positive sum game, as everyone winds up with more bandwidth (i.e.
everyone's WAP is now in 11 megabit mode), and it is possible that the parties we
contact may be interested in joining our network.
As Ralph Johnson has mentioned, the quick and dirty fix is to plant a
high-gain directional on the roof of the IMC aimed at Peter Miller's house.
Unfortunately, this fix rather truncates the growth of our network at the very
point that we are hoping it will grow from, namely the IMC.
Dave Young has mentioned installing a more powerful radio at PM's in order
to receive the weak signal from the IMC, as well as locking the network
into a 1 megabit mode. My understanding was that we were already using very
powerful 180mW (yes, I'm aware of the irony) radios from demarctech for our
nodes. Thus, we are already very close to the ERP ceiling imposed on
My suggestion is to put a better omni antenna on top of the IMC, and
possibly to install an amplifier there as well. This would have the effect of
turning the IMC into a "supernode" which would be able to reach much further
into the surrounding neighborhood, and pick up the fainter signals of the
Another option would be to install a second omni on the roof of the IMC to
create a phased array which preferentially broadcasts more of its energy in
the direction of PM's, but remains, for the most part, omnidirectional.
While this practice is somewhat common in amateur radio, to my knowledge no
one has tried it with 802.11B hardware. The phased array would be two
identical omnis fed by the same radio; a path difference of a certain fractional
wavelength would exist between each omni and the radio. That is, the coax
going to one antenna would be very slightly longer than the coax going to the
other antenna. The net effect of this would be that the interference between
the two antennas would alter their broadcast area into an assymetrical
shape, more like an ellipse than a circle, for example.
For the moment, without seeing what we have to work with, these are my
ideas. What this world needs is a good five cent 2.4GHz 30 dBi omnidirectional
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