by Jim Hanks

How often have you stood in the middle of a densely populated city only to find that you cannot get a signal with your cell phone? Most of us blame the poor coverage on our service providers. But is it always their fault?

Sometimes it's not. In this article I'll give you a few pointers that will enable you to get a signal where you normally cannot. But, first, let me present some background information on how cellular phones work.

Sending and receiving cellular signals
The name "cellular phone" is derived from the practice of dividing wireless coverage areas into hexagonal regions or cells. For instance, if you live within a community that is 100 square miles (10 miles x 10 miles), your provider might divide the area into 4 cells, each approximately 5 miles wide. However, if this area is in a densely populated city, obstructions and system traffic will encourage providers to set up cells that are much smaller (often they are only a city block wide).

In the center of each cell, a base station is positioned which consists of radio equipment attached to a cellular tower. This tower sends and receives signals over the range of frequencies assigned to each cellular service provider by the FCC. The technology used to transmit these signals is similar to FM radio technology, except that cellular transmissions are sent in both directions.

When you attempt to make a call, your provider assigns your phone a frequency on which to communicate with a base station. In order to initiate (or receive) a call, one of these frequencies (or channels) must be available.

So, why is your phone often unable to get a channel?

Transmission power levels
Cell phones and cellular base stations both transmit at fairly low power levels, thereby limiting the distances that their signals can travel. Now, you're probably wondering, "Why would providers intentionally limit the range of their signals by using low power transmissions?" Well, there are 2 reasons:

First, the FCC assigns each provider a limited number of frequencies to be used for calls. By dividing areas into cells and using low-power transmissions, these providers can use the same frequency for different calls in nonadjacent cells; since low-range transmissions ensure that signals will never overlap.

Second, high-power transmissions (like those you'd send with a CB radio) require much stronger batteries. Most people don't want to carry car batteries on the backs of their mobile phones.

So, given that there are a limited number of channels, the challenge for providers is to cram as many calls as they can into a single frequency. This is where digital technology becomes useful.

Digital vs. analog
Digital (or PCS) systems¹ are becoming the predominant wireless technologies because they allow more information to be transmitted on a single channel. Much like how music is stored on a CD, a digital wireless network repeatedly samples a voice call and converts it into binary code (a series of 1s and 0s). This code is compressed into digital packets and sent using only a portion of the frequency band. In digital format, up to 10 calls can be held on the same channel, along with features such as Caller ID, voice mail, and web browsing.

On the other hand, analog signals work by transmitting pulses of a voice call—much like cassette tapes do. Since analog signals require their own channels and cannot support the same features as digital signals, analog technology is quickly becoming obsolete. However, because analog signals use a lower frequency band (around 800 MHz) than PCS signals (around 1900 MHz), analog systems have greater range. Right now, analog systems also offer truer voice quality; but as technology improves, digital systems will sample at higher rates and approach the quality of analog.

If you have no idea what type of system your phone uses, here's a quick way to figure it out. If you enter a poor coverage area and you hear static until you lose your call, you are using an analog system. If your caller's voice has that underwater, garbled sound as you begin to lose him or her, you are on a digital system. The reason for this garbled sound is that as you lose reception, digital packets are being dropped. After a certain number of packets have been destroyed, the digital system terminates your call.

Other factors influencing reception (and a few remedies)
Besides the transmission technology, there are other reasons you might be getting poor reception. Fortunately, many of these problems are easily corrected.

Network traffic
Many people think that a poor connection is often caused by a glut of subscribers using the network at the same time. This belief is relatively unfounded. In digital systems, increased traffic doesn't usually impact voice quality since you can't set up a conversation unless the system is available. Once a frequency has been assigned to you and you initiate a call, space is allocated to your phone. For the most part, this is also true of analog systems. Unless a provider in the area has faulty network design, the only case in which high system traffic affects you is when you cannot receive the initial signal necessary to initiate a call. If this is the case, just keep trying. Your call clarity will be fine once you get a signal.

Terrain
Buildings, structures, and mountains can all obstruct the tower-to-subscriber path. As such, a slight correction of where your antenna is pointing is often the difference between service and no service. If you're on foot and buildings are your problem, improve your reception by making calls at street intersections. And don't make calls from deep inside buildings or before walking into an elevator.

If your company cannot receive cellular calls within your building, you might want to talk to your provider about getting a bi-directional amplifier. These devices are often used for conventions, when people within structures require cellular coverage.

Interference
You may experience interference from nearby electronic devices (such as computer screens, blenders, or power saws) while they are in operation. Walk away from these devices while you're on a call, or simply turn them off.

Weather
Everything from humidity to storms can affect the quality of a transmission. Arid days will deliver slightly diminished range because radio waves travel better through moist atmosphere. But if you need to make an important call when humidity is high and there is lightning in the area, expect problems. I have no advice for combating weather. Sometimes you can't beat Mother Nature.

Your antenna
If you're experiencing poor reception in a region that you know has good coverage, check your antenna. Many phones must have their antennae either completely pushed in or fully extended in order to maintain clear connections. If your antenna is only partially extended, you'll hear static or your call will get dropped. If your antenna is fully extended yet you still have constant problems in high coverage areas, there might be a problem with your phone. Call the customer service number found in your phone's instruction manual.

Battery
Often, your battery can be strong enough to attempt a call, but not strong enough to find a signal. Try to keep your battery charged to at least 2 bars on your battery indicator. Buying high-quality batteries (such as lithium-ion batteries) will give you more talk time and therefore more time during which you can obtain a signal.

Other technology
Unlike most countries, the U.S. did not adopt a standardized network when it jumped into the digital wireless world. As a result, the U.S. is experiencing more growing pains than seen in countries such as Finland (where GSM is the standard) and Japan (where CDMA is the standard). U.S. mobile phones support GSM, IDEN, TDMA, or CDMA. Each of these cellular technologies can impact voice quality as can the actual phone or system software. But the reasons why are pretty complicated and preferences are largely a matter of opinion.

Conclusion
So, if you've extended your antenna, you've recharged your battery, and the sun is shining down as you stand on a crest in the middle of Central Park, and you're still getting lousy reception, my last suggestion is to complain to your provider. Getting your company to install additional transmitters isn't always just a matter of the squeaky wheel getting the grease; often providers are unaware of coverage holes.

To notify your provider of poor reception areas, you can usually reach customer service departments for free by dialing 611 from your cellular phone. Or, if you can't get enough reception to do so, here are contacts for 3 of the major networks:

¹ PCS stands for Personal Communications Service. This service usually includes extra features such as Caller ID, voice mail, call forwarding, and web browsing. PCS systems use digital technology, yet operate on a different frequency than standard digital systems. Because the frequency assigned to PCS systems is higher, these systems have a shorter range and thus require more cells—and towers—than generic digital networks do.