I’m researching the feasibility of “unwiring” our community center in North Portland. The wireless proposal would tie students and teachers together. The school is just 4 blocks away and the neighborhood is tightly knit and has many low income families.

In order to lower costs, I was looking at cheap Wireless Bridges for client devices and stock 200 mW, 802.11b (which also provides hand-held compatibility in the neighborhood).

Anyway, I was thinking these products might work:

1. Two, 200 mW outdoor Engenius Access Points ($795) feeding 2, +14 dB gain antennas ($119) on the mast would cost about $2500.
2. Fifteen students and 5 teachers or advisors get a Wireless Ethernet Bridge ($90) with a +13 dB gain antenna ($35). With 20 of these units, the total cost would be about $125/each or $2500.

Some combination of end-user device would also be provided in each of 20 homes. I’m looking at D-Link’s DVC-1000 i2eye VideoPhone ($300), a $199 Playstation or X-Box, $199 Walmart PC running Lindows OS, $299 CD/RW Lindows machine or a $299 XP computer. Lots of slower Pentiums may also be used (at little or no cost) through Free Geek.

What kind of range can we get from a Linksys-type Bridge? It depends. A 200 mW, SMC Bridge with a +13dB panel might blast through trees and bounce around corners.

A Community LAN might supply 4 watts EIRP. The mast-mounted Senao 200mW SL-2011CD (+23 dBm) has a sensitivity of (-90dBm) at 5.5 Mbps and feed two, +14dB sector antennas. One points south (towards the school) and one points north (towards the housing). That should hit the majority of our clients. At the client-side, a +13dB flat panel or +16dB panel on the window-mounted, Bridge, might do the trick. I averaged the sensitivity (-86 dB) and power (+21dB) of the two radios to streamline the calculations and took off (-1.5dB) for cable losses on both sides (-3dB). Michael Young recommends a minimum of +10 dB to +20 dB “fade margin”. So let’s run the numbers on YDI’s calculator:

1. Range = .25 miles with +38.8 dB Fade Margin.
2. Range = .5 miles with +32.8 dB Fade Margin.
3. Range = 1 miles with +26.8 dB Fade Margin.
4. Range = 2 miles with +20.8 dB Fade Margin.
5. Range = 4 miles with +14.8 dB Fade Margin.
6. Range = 6 miles with +11.2 dB Fade Margin.

Twenty users might share a single $100/month DSL line. That’s $5/month. The wireless CPE including a flat panel, mount, pigtails, and a Linksys Bridge totals $200. Then add $300 for the computer or video game console. How long until a wireless PocketPC costs $150? About a year, I figure. So kids will have them. That’s why stock 802.11b for the “first mile” might be more useful than gear like Tsunami’s MP-11. With stock 802.11b, you can also flood the school yard and provide education-specific content. It’s cheaper, too.

Any high-school student can tell you; Wi-Fi is chump-change, cost/effective and cool. It could easily scale to 500 or more students. Add three, Vivato outdoor antennas and pull in those brain-dead home schoolers.

But what about software?

I’ve been reading about Microsoft’s new Office 2003 which has collaborative powers. An administrator can create a password-protected site that allows for file sharing and discussions and is navigable through any browser. Users can save to a SharePoint site directly from their Office XP applications. Here’s how to use SharePoint, a set of Web extensions that build the Office 2000 Server Extensions. But it’s way too expensive and far more complex than what we need.

So I looked though Open Source groupware for alternatives. They could include:

• Open Office, the Microsoft Office “clone” is free (or nearly so). OpenOffice 1.1 beta features new import/export formats such as PDF, Macromedia Flash, DocBook, several PDA Office file formats, flat XML and XHTML, Support for Complex Text Layout (CTL) and languages such as Thai, Hindi, Arabic, Hebrew.
• phpGroupWare is a multi-user groupware suite written in PHP. Its provides a Web-based calendar, todo-list, addressbook, email, news headlines, and a file manager.
• OpenWiki is a web based application offering a quick and easy way to post your thoughts to the web from anywhere and retrievable from anywhere. It can be collaboratively edited, by anyone or a selected few, using a web browser.
• Wikipedia is a multilingual project to create a complete and accurate open content encyclopedia. Started on January 15, 2001 they are already working on 112176 articles in the English version.
• The Collaborative Virtual Workspace is a software environment that provides a “virtual building” where teams can communicate, collaborate, and share information, regardless of their geographic location. For documentation, see the “Home Page” link above.
• Electronic Laboratory Notebook - (ELN) - a collaborative, web-based analog of the paper notebook. The ELN can be used to share and record text, images, 3-D molecular structures, live graphs, etc. and can be extended to support additional data types.
• Virtual Access Foundation VA is a well-established win32 mail news and collaborative conferencing tool, currently being converted to Open Source.
• LearnLoop is a web based GroupWare for collaborative learning with Forums, calendars, webmail, quiz, peer-review, etc.
• The Collaborative School Community Project is a system for collaboration and communication between the faculty and student body at K-12 school. Project elements include a homework submission and lookup database, class scheduler, and a web-based management interface.

Collaborative groupware and wireless are made for each other. Schools and students might be at the vanguard. Open source software could make it happen.

The Economist explains the latest in anti-plagerism software:

With a few clicks of a mouse, a student can outsource any academic chore to “research” sites such as Gradesaver.com or the Evil House of Cheat.

One market opportunity, however, frequently creates another. …The subscriber base of Turnitin, a leading anti-plagiarism software house based in Oakland, California, has risen by 25% since the beginning of the year. Around 150,000 students in America alone are under its beady electronic eye.

Turnitin’s software chops each paper submitted for scrutiny into small pieces of text. The resulting “digital fingerprint” is compared, using statistical techniques originally designed to analyse brain waves (John Barrie, the firm’s founder, was previously a biophysicist), to more than a billion documents that have been fingerprinted in a similar fashion. These include the contents of online paper mills, the classics of literature and the firm’s own archive of all submitted term papers, as well as a snapshot of the current contents of the World Wide Web.

According the Economist story, “…good universities, such as Duke, Rutgers and Cornell, employ it. Those that like to think of themselves as top-notch, such as Princeton, Yale and Stanford, do not. According to Dr Barrie, ‘You apply our technology at Harvard and it would be like a nuclear bomb going off.’”

Posted by Sam Churchill on Saturday, March 29th, 2003 at 10:16 am.