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[Ham-80211] Why? (was Handoff between access point? )

Larry Cerney lcerney at viawest.net
Thu Nov 25 01:20:24 UTC 2004

Hi Carl, et al;

Part 97 allows for much higher power and gain than the 802.11 limits set by
the FCC.  Off the top of my head I believe you should be legal up to 100
watts output, more than you'll need.  You MUST stay in the Ham band which is
I believe channels 1-3.

If you have the towers and want to fire up AP's on them it sounds like you
could set the AP up in bridge mode back to the 200' tower which I would
imagine would be the central hub location.  Pick a few towers and get the
hardware and experiment.  If it works out, expand.

If you can, go back and read some of the discussion on this list from about
6 months ago about IDing and access limiting and things like that.  I seem
to remember you must restrict access to Hams.  I don't know how large an
area you are looking to cover, but with 13 towers and some good antennas you
just might be able to do what you want to do.

Check out the Linksys WRT54G (embedded Linux) AP's.  They're pretty cheap (a
HAM MUST) and the Sveasoft software.  The sveasoft loads into the WRT54G and
allows you to boost the power out from about 20 mW to about 84mW among other
things like the WDS.  There are some problems with running them hot, but if
you burn one out they are cheap enough to replace.

Good luck and keep us all informed on your progress here on the list.


"The only reason for time is so that everything doesn't happen at once." 
--Albert Einstein 

-----Original Message-----
From: ham-80211-bounces at lists.tapr.org
[mailto:ham-80211-bounces at lists.tapr.org] On Behalf Of Carl Walthall
Sent: Wednesday, November 24, 2004 4:36 PM
To: TAPR Mailing List for Ham Radio Use of 802.11
Subject: Re: [Ham-80211] Why? (was Handoff between access point? )

Hi Larry

Thanks for the information! I have access to a small city wide 802.11B
network setup by a friend 3 or 4 years ago before he learned that he was
violating part 15. The system has 13 towers at 50 feet around the city and
the central tower is 200 feet. Each tower has a 5 watt amp and 14 or 24 DBi
antenna. Currently the system is running, but the commercial usage has been
discontinued. I started thinking about this because of the new 802.11 cell
phones under development and watching this group.

I was think the ham's here could use Voip to communicate with each other
using a laptop or maybe one of the new phones. We could use it for sending
emergency information during a disaster? But I am new to all this and just
experimenting until I make sure we are following part 97.

Thanks Again

----- Original Message ----- 
From: "Larry Cerney" <lcerney at viawest.net>
To: "'TAPR Mailing List for Ham Radio Use of 802.11'"
<ham-80211 at lists.tapr.org>
Sent: Wednesday, November 24, 2004 10:14 AM
Subject: RE: [Ham-80211] Why? (was Handoff between access point? )

> Carl,
> It is doable, technically.  A citywide network would need multiple access
> points spread throughout the city.  They must all be aware of their
> neighbors in the network and in its simplest form be on the same subnet.
> they are all on the same subnet, the mobile could retain the same IP
> across the city.
> Each AP would need connection to the internet via some sort of VPN to go
> back to a central hub subnet.
> Another way would be to build a mesh network in which AP's work together
> pass data wirelessly back to a central hub.  The problem with doing this
> as the data moves to the hub it is concentrated with data from other AP
> this reduces the effective bandwidth of the network.  This might not be
> critical if your only downloading email, but could bring down a network if
> you kid in the back seat is watching Lord of the Rings via the internet or
> down loading LL Cool J's latest CD. ;-)
> Do a Google search on Wireless Distribution Service or WDS which will
> explain how AP's can work together to pass data from AP to AP wirelessly.
> There will be other way of doing this in the future.  There has been much
> said about 802.16 wireless MAN networks which could be run under Part 97
> might come about commercially soon (next couple of years).
> As I said, it is doable, but don't expect to drive into a town and have
> mobile Internet access anytime soon.
> "The only reason for time is so that everything doesn't happen at once."
> --Albert Einstein
> >
> > Carl Walthall wrote:
> >
> > > Hi All
> > >
> > > If a person setup a large 802.11b network under part 97 city wide
> with
> > > multiple access points running infrastructure.  Could a person with
> a
> > > laptop in their car drive from one end to the other without losing
> > > connection? In other words, could the network be setup to handoff
> the
> > > connection from access point to access point the same as a cell
> phone
> > > would (Mobile IP)? I am sure its not the same, but could you stay
> > > connect as long as your getting a strong signal from a access point?
> I
> > > would also like to know the best place to read up on this subject?
> > >
> > > Thanks in advance
> > >
> > > Carl Walthall
> _______________________________________________
> ham-80211 mailing list
> ham-80211 at lists.tapr.org
> https://lists.tapr.org/cgi-bin/mailman/listinfo/ham-80211

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