A few years back, some friends and I had the crazy idea to utilize my MFJ-1800 2.4GHz Yagi antenna and a PC set up as a “reverse AP” to allow us all to use the hotel’s free wifi at a convention. The only downside to this was that we didn’t have wireless for ourselves, but that wasn’t too big of a deal: we had circumvented the pay access in the room using technology. Sadly, that hole was plugged the next year, and we were forced to pay for access… Such is life.

Moving forward to last year’s convention and our staying in a different hotel, I decided that I’d just suck it up and pay for access as it wasn’t too much. Though, before we actually settled down in the room that evening, I had ran by the T-Mobile store at the nearby mall and came extremely close to purchasing one of the webConnect USB sticks (which I now have) so we would have access without having to pay the hotel. I opted against that, but planned to get one before the year was out. Fortunately for me, T-Mobile had a promo for $10 less/month on the access not long afterwards, so I now have one to use for access mostly everywhere.

The obvious item for aircard owners with friends that attend conventions and trade shows is to pick up one of the aircard routers on the market. While I own a Soekris net4501 and have long thought to emulate the EVDO Stompbox Project using it, the lack of good driver support in OpenBSD for the Huawei UMG181 webConnect stick and my dislike of iptables had me pick up a Cradlepoint CTR350 broadband travel router to use. One thing I missed in the documentation was the client limit of 15 on its wireless. While I seriously doubt I’ll ever exceed that number, having a hard limit on the amount of clients that could be attached didn’t sit well with me at all, so I started brainstorming.

Back last month, I set up an old Power Mac G4 as an OpenBSD router using the macppc port. It functions flawlessly, and the flexibility of pf continues to shine. I thought about one of the major purposes that Soekris boards are used for and ran by Micro Center to pick up a good 2GB CF card to toss in it once I get OpenBSD built out on it. Fortunately for me, the author of flashdist has disk images set aside already for the net45xx series, which I will throw on the CF card sometime this weekend. The only downside to this setup is the utilization of “double NAT” in connectivity. Of course, this is no different than what we’ve already been using, so I really don’t see an issue with it.

Just how am I going to get around the 15-client limit of the Cradlepoint? While I certainly could use the Soekris as an access point: it’s one of those little green boxes’ primary uses, I’d much rather have a dedicated WAP set up like I do at home because of a couple of small things that may not work right: namely, UMA for my Blackberry. Just so happens I have an old La Fonera wireless router with DD-WRT loaded on it. I ran this as my WAP for a while at the house, and I reloaded it with DD-WRT before the convention last year and set it up as the WAP. While it works flawlessly, it gets rather warm. Not too much of an issue for a system that will run very infrequently.

Now how does this all piece together? Turns out that every single device I plan to connect together to create this connectivity backbone runs off either 5v or 12v DC. The two 5v devices, the Fonera and the CTR350, can be plugged into a 12v source using cigarette lighter sockets. The Soekris and my old Netgear EN108TP 8-port hub are 12v, so they will plug right in. My original plan involved debricking the WGR614L I toasted last year and using it as it was 12v and would reduce the amount of cig plugs.

The trick to this was building a small power distribution panel with screw terminals so they’d be very secure. Turns out this would be more of a pain than I originally thought, so I went back to the original plan that I thought of: using Anderson PowerPoles for the power connections and a power panel with those on them. In the end, deciding to go with PowerPoles for the power connections really was best: I won’t be tied down to the power supply, so I could feasibly run the setup off my car’s battery if I so decided. I probably will never do that, but it is an idea.

Converting standard wall current to 12v for the network devices was something I mulled over a lot with my original plan. I needed a small (10A or so) power supply with a cigarette receptacle on it. The smallest I could find at work was 25A and way overkill for what I needed. After I decided on PowerPoles, the decision was simple: Astron SS-10 switching power supply. It’s quite small and supplies enough power: 7A continuous, 10A 33% duty cycle. I seriously doubt all this hardware I have will ever exceed 7A for more than just a short period of time.

Now the really hard part is figuring out how to connect all of this together in a secure matter. I’ve done a lot of research in the past couple of days on the “go boxes” used by people who handle various events. One idea that probably won’t be too difficult to set up is to build a shelf and mount it in a case of some sort for carry. I’d probably pick something waterproof like an ammo box in case I get rained on for the convention like what happened last year. Otherwise, I’ll build out something very easy to set up and carry.

Overall, this is going to be one fun project. I’m very glad I have just over 6 months to get it set up! I do think that in the long run, streamlining my portable network setup will be very beneficial for myself, my friends, my family, and whoever else I can think of.

If anything, it’ll give me something interesting to write about as I continue to build it out.