Wireless IP for Canyon Rd.

I've been working with and using ``wireless Ethernet'' (802.11b) for a while now, both at work and at home. However, my initial approach to using wireless at home was the simplistic one: hang an ``access point'' (``AP''), acting as a ``dumb bridge,'' off of the internal network. I turned on WEP, restricted the AP to talk to only certain known MAC addresses, and configured the AP to not divulge the SSID in its beacons. And when I used the wireless net to access the machines I cared about, I did so via SSH.

Well, that certainly worked, and it had the virtue of (relative) simplicity. However, there was a concern: I wanted to migrate to a point where I could feel reasonably comfortable ``opening up'' access to the wireless net to those of our good neighbors who were interested in taking advantage of this. And no matter how much I trust our neighbors, I did not want them running around on my internal net. (For that matter, were the situation reversed, I wouldn't want to be running around on someone else's internal net, either.)

Long ago, I had placed a 3rd NIC (network interface card -- an Ethernet adapter) in my firewall machine. So the straightforward approach seemed to be to configure the firewall so the wireless AP was connected via the 3rd NIC, to a completely separate network. Well, around the beginning of October, I finally got the firewall re-configured in a way that seems to work OK:

So I think I'm just about ready to let some neighbors in on the fun. I expect that at first, I'll do it by manually "registering" their MAC addresses, until I get a feel for how well things are working.

But I think there may be an issue with getting the signal(s) where they need to be. Where my spouse & I live is a semi-rural area of Redwood City, just below Emerald Hills. And the ground doesn't tend to have too many horizontal planes around our area. Indeed, as the below diagram depicts, the upper part of our back yard is above the peak of our roof; our garage is under our (nominally single-story) home; the floor of the garage is about 5' above the street. And the ground across the street is below street level (the creek that inspired the name for Canyon Rd. runs in back of our across-the-street neighbors' houses).

Profile of lot, looking west

We see here a rough diagram of the profile (looking due west) of the area where our house is. The salient features, from the left, are:

I'm thinking that the better part of valor would be to see if my neighbor (across the street) -- who has a ham license... -- can cobble up enough of an antenna to get our signal the way things are right now. If so, we should be able to experiment without needing to deal with lengthy cable runs, weather exposure, lightning protection, and expense -- not one of which seems like something I'd miss terribly.

An idea that recently (July, 2002) occurred to me -- as a means of reducing the exposure to damage even in the event of an admittdely rare lightning strike, if nothing else -- would be to use a passive reflector on the top of that post, and beam the RF to it from the house. I'm not sure how good an idea it is, but it is still an idea....

Comments? Please send them to wireless@catwhisker.org -- thanks!

$Id: wireless.html,v 1.5 2002/07/07 04:02:46 david Exp $