Why cell phones still hit 'dead spots' sometimes

Gary Krakow Columnist • E-mail

I get a lot of reader e-mail in response to my technology columns — much of it unprintable. But many of the questions are more basic: Why doesn't this stuff work? How do I get it to work? What should I look for when buying something that will work? And why aren't we all flying around in jetpacks already?

Starting today, I'm going to take up these questions on a regular basis (well, not the jetpacks, but we will discuss equally mythical tech promises from time to time) and try and shed some light on the confusing consumer nightmare that is often our digital world. Got a question? Fill out the form to the right, and please include your first name and hometown.

In today's installment, A.P. Garcia from San Benito, Texas, wants to know why there are "dead spots" in cell phone coverage, Cindy from Sacramento seeks a cell phone that will work in China and Mike from New Jersey is trying to connect his iPod to his car.

Why are there "dead spots" in cell phone coverage?  I live about a 1/2 mile from several cell phone towers and this situation has me confused.
A.P. Garcia, San Benito, Texas

Why is it that I cannot use my cell phone inside my house? I have to go outside to be able to get a minimum signal. ... I have been with Verizon until early last year and then switched to Cingular thinking that they can provide better service. You guessed it — the service I get is the same as with Verizon — zero, ziltch, poor.
Zgoblu, Irvine, Calif.

Both questions have similar answers. Cellular phones are really sophisticated two-way radios — think of them as very intelligent walkie-talkies that operate on more than 1,600 channels.

When you use a mobile phone, it sends and receives signals to and from radio cells located on local broadcast towers — hence the term, cell phone. Local cells in your area decide which one is getting the best signal and that one handles your phone call. If you are moving, either in your car or just around your house, the actual call may be transmitted and received by a number of different cells — depending on which one is best.

Your cell phone broadcasts and receive on very high frequencies at very, very low power levels. That’s so you don’t fry your brain when you hold your phone next to your ear. The cells that send and receive the signals are also low power. That’s how come so many cells can co-exist on the same tall cell tower.

It also means that cell phones are subject to interference from everything and anything that can get in the way, both electrical and physical.

When everything works well, then all is right with the world. But this is not a perfect world. Sometimes there aren’t enough free cells to handle your call. Sometimes, even at maximum power, your cell phone signal simply isn't strong enough to reach the cell tower. Or there could be a large object in the way, such as a tree, a wall — or even just a large truck passing by.

For the most part, larger or better antennas for your cell phone might help with reception, but don't really exist. Could you imagine walking around with a 12-inch antenna on your 4-inch long phone? Same for boosters. If someone claims you can stick something on your phone and achieve better reception, forget it. The only thing it will help is the seller's bank account.

If you have signal problems, your best bet is to just keep moving around while you're on the phone until you find a spot with good signal strength. When you find it, stop moving until you're done with the call. If you’re indoors, try using your cell phone near a window — or, sorry, go outside.

I'm going to China soon and would like to contact my family while I’m there. I’ve been told my cell phone won’t work there but what about e-mail? Is there something I need to add to the e-mail address to get it to the USA?
Cindy, Sacramento, Calif.

Your cell phone probably won’t work in China, unless you currently use a GSM handset. GSM is a cellular transmit/receive technology in use almost everywhere on the planet. In this country, however, many of the big wireless companies use a different standard. T-Mobile and Cingular, however, both use GSM. 

Having a GSM phone may not be enough, however. Your particular handset may not work properly with foreign phone systems in each locale. But most people won't want to buy a new phone unless they plan to travel to a particular country on a regular basis.

Instead, consider renting a phone for the trip — it's cheaper and easier to do than you might think. A quick Internet search for "China cell phone" should give you a list of companies that offer rental services, such as Roadpost and Planetfone. In addition to a flat fee for the rental and a delivery fee (they'll mail it to your U.S. home before you go), you will also need to purchase a SIM (a small memory card with your phone account information) and either load it up with prepaid minutes or arrange to pay as you go. If you run out of minutes, you can always purchase more. Actual costs will vary by vendor and country.

Another approach would be to rent from a local provider once you're at your destination, or even buy an inexpensive handset outright.  You will again need to buy a SIM as well. This is usually a cheaper option than the one outlined above, but can also be more hassle.

As for e-mail, unless you're in a very remote area of China (and even then you might be surprised), you should be able to cheaply rent an hour or two of time from one of the many local Internet cafes.  If you have a Web e-mail account now (i.e., one that you can log into from a Web browser, instead of or in addition to using an e-mail program such as Outlook), you should be able to access it from anywhere with Web access.

However, security at Internet cafes (not just in China) can be a dicey matter — it's not necessarily the proprietor who's the risk, but whoever used the computer right before you (or a week before). So many people prefer to create a special e-mail account, just for use on a trip, and then delete it once they're home. You can set up a new free e-mail account easily with services such as Google's Gmail or Microsoft's Hotmail or Yahoo! Mail. Sending e-mail from these accounts works just the same whether you're in China or in the U.S. -- if you don't know your family's e-mail addresses by heart, you can add them to the new account's address book or just write them down on a card.

Lastly, it should hopefully go without saying that an Internet cafe in the middle of a foreign country is NOT the place from which to check your online banking account.

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