The Basic Guide to Cell Phone Signal

Introduction

More than 95 percent of the population owns a cell phone today, with smartphones accounting for 77 percent of that ownership. Much of the time, these phones work reliably, allowing calls, texts, and data transmission. However, many users lack a solid understanding of how cell signal originates and functions.

Cell phone signal connects users across networks. It functions similarly to two-way radios: a signal transmitter sends a signal to a receiver. When you speak on a cell phone, your voice is converted into a radio wave signal transmitted to the nearest cell tower. The tower then relays this signal back, converting it to sound for the recipient.

A strong cell signal ensures seamless communication. Weak signals, however, lead to dropped calls and stalled data transmissions.

How is Cell Signal Measured?

Cell phone signal strength is measured in decibels (dBm) received by a mobile phone from a cellular network. Strengths typically range from -30 dBm (strongest) to -110 dBm (weakest). A number closer to 0 indicates a stronger signal. A signal better than -85 dBm is considered good.

Mobile devices display signal strength using bars, but these are not an accurate measure. There's no industry standard for what a bar represents, and it can vary based on the carrier (e.g., Verizon vs. Sprint), how the phone is held, the manufacturer, and device activity.

Illustration of a smartphone displaying signal bars.

Using Field Test Mode

Determining the dBm directly on your phone via Field Test Mode offers a more accurate signal strength measurement than relying on bars. This mode is available on Android and Apple iOS devices.

Field Test Mode for iPhone

Field Test Mode on iPhone provides detailed information about signal, cellular connection, and providers. It displays signal strength as a number rather than bars or dots. Note: This feature may work differently on iOS 11 and newer devices.

Requirement: An active cellular connection is necessary.

*Instructions may not work for iPhones using iOS 11 and higher. Visit weboost.com/signalstrength for updated instructions.

1. Open the "Phone" app and dial: *3001#12345#*
2. Press the "Call" button to launch the hidden "Field Test Mode" app.
3. Select "LTE" from the main menu.
4. Select "Serving Cell Meas".
5. Find "rsrp0." The corresponding number is the cellular signal strength in dBm.

Visual guide showing iPhone dialer, Field Test Mode main menu, Serving Cell Meas screen, and signal strength (rsrp0) details.

Field Test Mode for Android

Navigate to your phone's menu (screen locations vary by manufacturer, model, and OS version).

Method 1:

1. Navigate to "About Phone".
2. Select "Status" or "Network".
3. Look for "Signal Strength" or "Network Type and Strength."

Alternate Navigation:

1. "Settings"
2. "More Options," or "More Settings"
3. "About Phone"
4. "Mobile Networks"
5. "Signal Strength"

For older Android devices:

1. "Open Settings"
2. "General"
3. "About Device"
4. Select "Status" to display signal strength in dBm.

If you cannot find the signal strength, consult your device's operations guide or use apps like SignalCheck Lite from the Play Store.

Remember: The closer your dBm number is to zero, the stronger the signal (e.g., -50 dBm is strong, -100 dBm is poor). Cell signal is strongest near cell towers, but environmental factors can impede it.

Visual guide showing Android settings menus leading to signal strength information.

What Blocks Cell Signal?

Dropped calls and stalled transmissions can occur even in areas with many cell towers. Cell signal can be blocked by natural barriers like mountains and thick forests, and by building materials such as brick, steel, concrete, and certain types of glass indoors.

As the number of cell users increases, networks become congested, leading to service lags at events with many people using mobile devices.

Illustrations depicting natural barriers (mountains, trees) and urban buildings, symbolizing signal obstruction.

How Can Cell Signal Be Improved?

Poor cell signal can be frustrating. While many blame their network carrier, external factors often cause signal issues regardless of the network. Even strong networks struggle against dense building materials or natural obstructions.

Fortunately, cell signal boosting technologies offer solutions to improve coverage, even in challenging areas.

How Do Cell Phone Signal Boosters Work?

Despite improvements in 4G and LTE, service gaps persist. Cell phone booster systems capture and amplify existing cell signals, offering scalable solutions for homes and large commercial buildings. These patented technologies enhance available signal strength.

Boosters use antennas to pick up signals from existing towers. These signals are then electronically amplified and redistributed throughout a location via smaller antennas, potentially increasing signal strength by up to 32 times. Boosters can be installed zonally, allowing for customized coverage improvements, with commercial installations often requiring more antennas than residential ones.

A diagram of a cell tower emitting radio waves, symbolizing signal transmission.

Active vs. Passive Distributed Antenna Systems (DAS)

Cell phone boosters are based on either active or passive DAS technology.

Active DAS creates cell coverage by generating and distributing its own signal. These systems require complex, hardwired fiber optic networks, making them costly and infrastructure-intensive, often prohibitive for average consumers. Costs can range from $2-$4 per square foot for single-carrier solutions and up to $10 per square foot for multi-carrier solutions.

Passive DAS offers a more feasible and affordable option. It uses existing cellular signals, requiring less invasive and more affordable installation, typically costing between 30 to 70 cents per square foot. Passive DAS solutions are carrier-agnostic, benefiting all users regardless of their network carrier. They capture existing signal via donor antennas, route it to a booster for amplification, and redistribute it through smaller broadcast antennas.

Diagrams illustrating the concept of Distributed Antenna Systems (DAS), comparing active and passive approaches.

Conducting a Site Survey

Choosing the right antenna requires a site survey to identify areas with strong and weak signal. Relying on phone bars for assessment is misleading. A survey accurately determines the best location for a donor antenna for maximum efficacy and estimates necessary cable and accessories.

Professional installation experts use a signal meter, a handheld device, to detect and display signal frequency, bandwidth, and strength with certainty during a site survey.

An image of two individuals in hard hats reviewing a plan or blueprint, suggesting a site survey or installation.

Choosing the Right Antenna & Benefits of Cell Signal Boosters over Wi-Fi

Choosing the Right Antenna

A site survey helps determine the type of "donor" (outdoor) antenna needed to capture signal for indoor amplification. Donor antennas are critical for the system. They are installed on the roof or near windows to capture outdoor signals. Indoor broadcast or "inside" antennas (panel or dome) then transmit the amplified signal.

There are two main types of donor antennas: omnidirectional (omni) antennas, which receive signals from any direction, and directional (Yagi) antennas, which are highly directional and receive signals from a specific direction.

The installer must identify the strongest signal source and potential interference to select the best antenna for a location.

An illustration of a directional antenna.

Benefits of Cell Signal Boosters over Wi-Fi

Many users rely on Wi-Fi when cellular connections fail. However, Wi-Fi can be insecure, putting uploaded or downloaded data at risk of snooping and cyber-attacks. Wi-Fi networks are inherently more susceptible to these threats.

Cell signal boosters improve signal strength while keeping data secure. They also provide faster upload and download speeds compared to Wi-Fi connectivity.

Carriers Endorsing Passive DAS

Major cellular network providers are shifting towards carrier-agnostic solutions, allowing all users to benefit from existing infrastructure, regardless of their carrier (Verizon, Sprint, AT&T, T-Mobile). This move is driven by the realization that improving cell signal benefits everyone.

Historically, carriers were concerned about boosting solutions negatively impacting their networks. However, Federal Communications Commission (FCC) regulations mandated in 2014 established standards to prevent this, creating a win-win for carriers and customers. WilsonPro has been a leader in passive DAS solutions and partnered with the FCC on these standards.

As 5G technology develops, carrier-agnosticism plays a crucial role in achieving a true 5G network.

An image of a WilsonPro cell signal booster device.

Boosting Cell Signal Where You Need It

If you're interested in improving cellular signal in your home, or if you manage a building and need to enhance signal for tenants, WilsonPro offers solutions. They provide a variety of passive DAS solutions configurable for buildings and spaces of all sizes.

Contact WilsonPro to learn more and start benefiting from reliable cellular connectivity.

Illustrations of a smartphone receiving a signal and a cell tower broadcasting signals.