As companies like Nextel Communications and Sprint PCS eagerly upgrade their data offerings to lure more customers to access the Web wirelessly, they may be sowing seeds for a future gridlock.

Just as dial-up modem users have trouble going on-line during peak hours, wireless Webheads could face a similar fate, a Purdue University researcher warns.

"The problem will be when numerous users want to download from the Web through wireless links at the same time," said Michael Zoltowski, a Purdue engineering professor. "The interference created will choke the wireless Net connection."

The answer may be giving wireless handsets multiple antennas, Zoltowski said in a report presented to an international signal processing conference last month.

Putting two or more antennas on a wireless phone or laptop computer could expand the capacity of the wireless Net by three times and would vastly improve reception, he said.

Interference can be generated when radio signals bounce off buildings to arrive at different times and when a cellular handset gets signals from two different base stations, causing confusion. In both cases, having a second antenna can help sort out the problem just as having two ears helps people to hear better, Zoltowski said.

Theoretically, the most sophisticated digital wireless phone systems should accommodate up to 64 users in each band of radio frequency at the same time.

"But the reality is, because of these kinds of interference effects, they can only allow about 20 users in a given band, or, at most, one-third the potential number," he said.

Computer simulations suggest that putting two antennas on a cell phone can solve the problem, the Purdue researcher said. But that solution isn't without its own problems because additional antennas will increase the energy consumption of the handset and reduce battery life.

No missing links: A problem proposed 32 years ago to challenge computers has finally been solved by a group of Midwest-based researchers using more than a thousand computers around the world working on it.

Researchers from Northwestern University, Argonne National Laboratory and the University of Iowa used software developed at the University of Wisconsin to link the computers.

Even though experts didn't think the current generation of computers is advanced enough to solve the problem, the machines did the job in just under a week once they were harnessed to work on the same problem.

The problem concerns discovering the best way to locate 30 facilities, each at a separate site, so that transferring materials from one location to another will take the least effort.

This is a common type of problem faced by designers of factories, hospitals or other buildings where a lot of material is regularly transferred from one spot to another.

The researchers programmed computers to eliminate possible combinations that couldn't possibly lead to an optimal configuration. They then used a computing system called Condor to enlist 1,000 or more computers hooked to the Internet to work on the problem when they weren't busy doing other things.

"The availability of this powerful, easily programmable, low-cost computing platform has tremendous implications for the solution of complex optimization problems and for computational science in general," said Jean-Pierre Goux, a research associate at Northwestern and Argonne.

Featured speaker: Christie Hefner, chief executive of Playboy Enterprises Inc., will deliver the keynote speech to the big Midwestern Internet confab, called Chicago Internet World 2000, which will be held Tuesday through Thursday at the Hyatt Regency Chicago.

Other hot Internet topics like the Linux system and cable modems for high-speed connections will be discussed when convention-goers aren't playing with new gadgets.

Next month more than one thousand educators from across the country are expected to come to Chicago for the SchoolTech Exposition & Conference held at the Hilton Chicago and Towers.

That gathering will help teachers learn to create Web sites, introduce them to new wireless Web technology and hold discussions of how to integrate computer material into the existing curriculum.

Space mines: When the day comes that we mine and process materials on the moon or Mars, the National Aeronautics and Space Administration wants to be ready, and it has enlisted a local firm to help.

Packer Engineering Inc. of Naperville is doing some experiments to help create software that simulates processing metals in low gravity. The firm is designing an experiment that will fly on NASA's space plane later this year and will design an experiment that will be done aboard the space shuttle or space station later.

While the long-range purpose of this work may help design materials processing operations years or decades from now in space, there also is a shorter-term goal, said firm Chairman Ken Packer.

"As we learn more about the effects of gravity on casting and other processes, it will enable us to make better materials right here on the Earth," Packer said. "This knowledge will translate into things like lighter-weight engines."

The Packer project is being headed up by Vicky Demas, who is a senior at the University of Illinois at Urbana-Champaign.