[UFO Chicago] Re: [LUNI] Softroad

Nate Riffe inkblot@geocities.com
Mon, 25 Jun 2001 15:57:10 -0500 (CDT)

On Mon, 25 Jun 2001, Peter A. Peterson II wrote:

> Quoting Nero Wolfe:
> > My real questions would center around what kind of wattage can we put out?

Wattage is very limited.... think Antenna Gain instead .

> > and what kind of gain the antennas will have... and then... how much would
> > it cost to set up a node...  Even out of morbid curiosity, even just to
> > have internet in my neighborhood :-)

At current prices, a node with one omni for client nodes and one
directional for an uplink will cost at bare minimum about $600.  At relay
(two point-to-point links) costs about the same.  A combination of the two
(that's one omni for clients, and two directionals for infrastructural
connectivity) starts at about $800.  For a client-serving node that
connects to an existing land line, the cost is significantly lower,
starting at about $325.

The hardware list:

A node with a wireless uplink serving a single client cell:
1) 1 486/Pentium computer	< $50
2) 2 WiFi cards /w ext. ant.	$250 ea.
3) 1 omni antenna		$25 and up
4) 1 directional antenna	$25 and up

> Well, there are apparently a lot of variables that come into account --
> for example, whether you're using the antennas omni or unidirectionally,
> how high the antennas are, what legal power limits are, etc. Pricewise,
> they're not as bad as you might think

I read the relevant FCC regulations a few weeks ago just to get a sense of
what sort of antenna gain was acceptable.  Please note that almost
everything I know about radio technology and wireless networking is all
new to me, as well.  I have done some non-trivial homework over the last
few months.

For the 2.4Ghz band (utilized by WiFi devices, et al):

The band is divided into 11 channels, but I forget what the channel
bandwidth and attenuation requirements are.  Maximum omnidirectional ERP
is 1 watt.  Frequency Hopping Spread Spectrum (FHSS) is allowed, but
deprecated, and Direct Sequence Spread Spectrum (DSSS) is preferred
(mandatory for new devices?); one or the other is mandatory.
Point-to-Point links have special rules that allow you to do more, as long
as identical data is not being sent out multiple antennae (which would
effectively make it omnidirectional).  Point-to-Multipoint must obey the
same rules as omnis.

Those are the rules... Let's Get It ON!

> Nate Riffe would be a better person to ask about all that.

Somehow I never really imagined myself in this position... funny, that.

> Hopefully UFO
> will have a meeting at some point in the near future with a discussion
> about this specifically on the docket, with price information and
> distances, etc. Another important question is how do you get on top of
> tall buildings? I was thinking about the possibility of starting a
> not-for-profit organization that approaches building owners with the
> proposition for allowing us to use rooftop space that they could
> potentially be able to deduct as a donation (especially if they already
> lease space to cellular companies).

I thought about that, too.  If someone wants to take on that job, then by
all means go for it.  Sales, Marketting, and Talking To People Who Aren't
Interested In What I'm Telling Them in general aren't really my cup of
tea.  However, I can provide a list of buildings I would eventually like
to have antennae on :-).

> I'd need to talk to a tax lawyer
> about this, of course. Who knows, maybe some companies would even donate
> equipment. (Probably not, with the current economy though.)
> pedro


Nate Riffe			Bring me a selection of the finest meats
inkblot@geocities.com		and cheeses your nation has to offer!