An 82 mile link across the Great Salt Lake may soon be eclipsed as better WiFi chips and MIMO antennas boost range.

Atheros Xtended range chips claim receive sensitivities up to -105dBm. That’s more than 10 dB better than other 802.11 chips. Twice the range. Easy.

It’s used in Netgear’s access points and other “Super G” products. D-Link firmware may double WiFi range while remaining compatible with 802.11g and 802.11b networks.

FCC regulations say a 2.4 GHz client can use a 30 dBm transmitter with a 6 dBi antenna. For every 3 dB increase in antenna gain, the transmitter power output must be reduced by 1 dB. Clients are classified as point-to-point so their EIRP can exceed 4 watts. Refer to the following table:

How about testing a 100 mile long shot. Is it possbile? Probably not. But here’s what I’d try:

• Two Xtended Range devices on each side would use -105dB (+15db output) chips.
  ($100 each) x 2 = $200
• Two, 250mw “G” bidirectional amps increase the output of the 30mw radio (+15db) to 250mw (+23db) That’s ($329 each) x2 = $650
• Two, 23dB dishes ($75 each) x 2 = $150
• Optionally, two 1.2 megapixel Toshiba Netcams ($600) or DLink Webcams like the D-Link’s Securicam ($449, with pan, tilt, CCD Sensor, mike and MPEG-4) or D-Link Videophones ($150-$250) could be used on each end.

For less than $2,000, you might break a record AND showcase cost/effective technology. That’s better than $2k spent in advertising. It combines the maximum FCC legal output (250mw) that can feed a +23db to +27db antenna, coupled with the maximum sensitivity 802.11b chip (-105db) and maximum video compression (MPEG-4). Add a Single Chip MPEG-4 Audio Video CODEC and a Motia Smart Antenna for good measure.

The Atheros 5004x brings “Xtended Range” to the 5.8 GHz band. You might feed a couple Proxim MP.11a bridges ($600) into a 500mw, 5.8 GHz amp ($675), with a 28 dBi 5.8 GHz flat panel ($535) on each side. That’s cheaper than a couple of $5,000, 802.16a bridges. It might get you 15-20 miles. Easy. The Atheros 5004x chips might be available in $120, 5.8 GHz bridges or USB clients. An external +21dB panel might deliver the “last mile”. Cheap.

QuickTime Broadcaster allows just about anyone to produce a live broadcast event — direct from Mount St. Helens, for example. QuickTime Broadcaster sends out a single stream that can be viewed by one QuickTime Player. If more than one QuickTime Player will view your broadcast you will need access to a streaming server or a multicast-enabled network. The combination of QuickTime Broadcaster, QuickTime Streaming Server 4 and QuickTime 6 provides the industry’s first end-to-end MPEG-4-based Internet broadcasting system. Real’s Helix Producer 10 and Helix Gateway Server, can perform similar duties. Real’s Mobile Server delivers live and on-demand MPEG-4 over the Internet and to 2.5G and 3G cellular networks.

A remote software access point, running on a laptop 30-50 miles away, might support multiple presenters using WiFi locally.

• Microsoft Portrait could provide mobile videoconferencing using PocketPCs velcroed on everyone’s jacket.
• A “radio station in a box” provides streaming audio before and after the live event, along with a slide-show.
• Earthview lets anyone do real-time, cosmic zooms and 3D flybys into hundreds of cities, inexpensively. Broadband delivers 7 terabytes of realtime satellite and aerial photography to a PC. It features 1 meter resolution and advanced analysis tools.

There’s your emergency network. For the people.

FEMA, DHS and first responders will talk amongst themselves. This network would deliver public services over the open internet. Broadcasters may not be much help. Radio is satellite fed and television has less staff and motivation. Bloggers and camphones can suppliment newspaper and television coverage with on-the-spot live feeds. The Internet was designed to survive a nuclear attack.

Students, community LAN activitists, and local businesses are untapped assets. A network plan that benefits everyone wouldn’t be hard to define. Stuff it into 3-4 flight cases. It’s a class project. Students could build it. Volunteers could run it. Schools could use it.

YDI’s Operating Margin Calculator can help you estimate operating range. Show everyone that you can pan, tilt and zoom a remote camera 10-20 miles away (without amplifiers) and further with an external amp. Soon, 802.16a antennas will be going up on a broadcast tower near you. Plan on it.

I smell a grant!

Posted by Sam Churchill on Thursday, January 8th, 2004 at 7:23 am.