Engineering Articles

Judging a Gadget by Its Coverage

"TIRED OF SPOTTY cell phone coverage? We've got the solution for you!"

Wireless Extenders, a company based in Norcross, GA, has released a product dubbed the YX500-PCS Wireless Extender. It is supposed to provide improved in-building coverage for suffering cell phone users who are experiencing poor signal strength indoors. According to the manufacturer, approximately one third of the wireless subscribers in the U.S. have in-building coverage problems. Somehow that number seems much lower than I would have expected. Nonetheless, that adds up to 50 to 60 million consumers who may be interested in a product like this. The device only works with PCS phones operating at 1850 to 1990 MHz.

Meanwhile, a different company is launching a similar gadget geared for consumers who use their cell phone in their car. Illinois-based Richardson Electronics is manufacturing a new product called the Call Capture. Richardson Electronics claims the device will improve the signal strength and coverage of cellular phones inside a car.

While I do not see these products replacing the need for more antenna sites any time soon, they may entice some misguided person at a zoning meeting to say, “Why can’t everyone use a signal amplifier instead of companies having to build those ugly towers?”

Hopefully these devices really do work, which will increase cell phone usage, increase revenues for our clients, and decrease network capacity. ■

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Up, Up and Away...

SEVERAL TELEVISION STATIONS and newspapers are talking about a company called Sanswire Networks. They claim to be close to completing a prototype of an unmanned airship that is will deliver mobile phone service from the Earth's stratosphere and replace cellular telephone towers altogether. I am very skeptical. Let me tell you why.

Many companies have tried to resurrect the popularity airships had before World War II. The U.S. military used airships for a variety of purposes. Each time the effort was scuttled. Other companies thought airships could be used as sky cranes. Those efforts also failed. Now someone wants to put high-tech balloons at an altitude of 65,000 feet to provide wireless telephone coverage to 180 million subscribers? Say it ain't so, Joe.

Sure, technology has come a long way since the 1930s and 1940s, but I am reminded of the promises of Motorola's Iridium debacle. Remember, they were going to replace towers, too. I just don't see how a network of airships can provide seamless cellular telephone coverage efficiently and cheaply.

Let me tell you a short story. Several years ago when I moved to Madison, WI I purchased my first satellite TV receiver. The only problem was that my satellite TV provider did not offer local Madison, WI channels. They did offer local channels to the people of Milwaukee, WI, though. I asked them if I could have Milwaukee, WI channels instead. I was told "no." I then asked them if my receiver was technically capable of receiving the spot coverage of the Milwaukee, WI channels. They said I was too far outside of Milwaukee for the beam to even hit my dish. They were wrong.

I also had a Milwaukee, WI address. I told them (I know, I'm a bit ashamed of this, but no one got hurt in the process) that my receiver was in Milwaukee and my billing address was in Madison. Which was true; my receiver was in Milwaukee...for a brief time. They turned on the Milwaukee, WI local channels and instantly they were transmitted to my living room in Madison, WI.

Where am I going with all this? According to Sanswire Networks, these blimps will cruise at 12 miles above and provide coverage to 300,000 square miles on Earth. They also say it will only take 12 airships to provide coverage to most of North America. While I am not an engineer (and nor do I play one on TV), I find it hard to believe Sanswire Networks can have an airship at that altitude and transmit signals with pin-point accuracy.

Yes, I have many questions about this application. Even if Sanswire Networks could deploy these airships with the most sophisticated phase array antennas (like the radar used on the F-14 Tomcat), how much would all of the necessary antennas, batteries and equipment weigh? What kind of equipment will be needed to provide coverage to 500,000 or more subscribers over 300,000 square miles? How much power will a phone need to transmit to transmit to a blimp flying 12 miles up in the sky? How will battery life be affected? How big will the antenna on the phone need to be? These are all issues that plagued Iridium.

Can Sanswire Networks overcome all these hurdles? I think not. ■

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