10 dBi Antenna Range Calculator

Introduction

This tool computes the maximum range or distance (in meters, feet, miles or km) that can be achieved with a 10 dBi gain antenna.

The communication system includes a transmitter, receiver, antennas and cables.

Calculator

To calculate the max distance, enter the following:

  • Frequency of operation (Hz/KHz/MHz/GHz)
  • Transmit Power (dBm)
  • Receiver Sensitivity (dBm)
  • Receive Antenna Gain (dBi) – the default value is 2 dBi
  • Total Cable and Other Losses (dB)

Formula

The calculator uses the Free Space Path Loss (FSPL) equation:

PTx – PRx = 20*Log10(d) + 20*Log10(f) + Lc + 20*Log10(4Ï€/c) – GTx – GRx

The distance d is given by

Log10(d) = (1/20)*(PTx – PRx – Lc + GTx + GRx – 20*Log10(f) – 20*Log10(4Ï€/c))

Example of a Practical 10 dBi Antenna

The picture below shows a 10 dBi Antenna used in Wi-Fi applications

WiFi Antenna Dual Band 2.4GHz 5.8GHz 10 DBI RP-SMA Router for PCI-E WiFi Network Card USB Wireless Adapter Security IP Camera and ASUS RT-AC68u

It’s dual band covering both 2.4 GHz and 5.8 GHz. We could not find a data sheet for it, but based on the physical design, it’s an example of a monopole antenna.

Example Range Calculation

At a frequency of 2.45 GHz (Wi-Fi band) and transmit power of +20 dBm, let’s calculate the range for a 10 dBi transmit and receive antenna

With

  • Receiver sensitivity = -90 dBm,
  • Cable loss = 0 dB

the maximum range is 30,793 meters or 30.8 km.

Note the difference in range for the same power level between the 10 dBi and 5 dBi which covers a distance of 9.7 km.

The 10 dBi antenna therefore has over 3x the range of the 5 dBi.

Important to remember that this calculation is outdoors and in free space which represents an ideal signal propagation condition. In practice, the range would be lower.

How to use the Calculator

Below is a list of the terms used in the calculator and what each of them mean.

Frequency of operation

This is the frequency at which the communication system operates. At lower frequencies, wavelength is commonly used and if that’s the case, then use the wavelength to frequency converter.

Transmit Power

This is the power at the output connector of the transmitter. It is usually specified in dBm. However many vendors specify this quantity in Watt. Convert from Watt to dBm.

Transmit Antenna Gain

This depends on the type of antenna used and is expressed in dBi (dB relative to isotropic antenna).

Total Cable and Other Losses

This includes losses between connectors and antennas. If RF Splitters are used, the loss should be accounted for as well. It is specified in dB. Use this calculator to find the loss due to antenna cable.

The sum of the Transmit antenna power and Gain minus cable and connector losses is also called Effective Isotropic Radiated Power or EIRP for short.

Receiver Sensitivity

Minimum level of input signal that a radio receiver can detect and demodulate. Use this calculator to find the sensitivity as a function of temperature, SNR and receiver noise figure.

Receive Antenna Gain

Depends on antenna used and is expressed in dBi. In cases where the signal is from a particular direction, a high gain antenna (8 dBi for instance) can be used. This allows focusing of energy instead of receiving from all directions. Antenna gain can be calculated from the Antenna Factor and frequency of operation.

Background

A 10 dBi antenna is designed to offer higher gain compared to lower dBi antennas, making it more directional and capable of transmitting or receiving signals over longer distances. The increased gain of a 10 dBi antenna means it focuses the signal more narrowly, which can significantly enhance the signal’s reach and quality in its preferred direction.

Applications

Here are some common uses for a 10 dBi antenna:

  1. Long-Distance Wi-Fi Links: For establishing Wi-Fi connections over longer distances, a 10 dBi antenna can provide the necessary range, making it suitable for connecting networks between buildings or across extensive outdoor areas.
  2. Fixed Wireless Broadband: In rural or remote areas where cable or fiber internet is not available, ISPs (Internet Service Providers) may use 10 dBi antennas to deliver internet service to customers’ homes from a central wireless tower.
  3. Directional Links: For creating point-to-point (PtP) wireless links, a 10 dBi antenna can focus the signal tightly between two locations, optimizing bandwidth and connection stability over considerable distances.
  4. Outdoor Surveillance Cameras: To ensure reliable wireless communication between outdoor surveillance cameras and the monitoring station, especially over large properties or in challenging environments, 10 dBi antennas are used.
  5. Amateur Radio and Ham Operators: Ham radio enthusiasts might use 10 dBi antennas for specific VHF/UHF applications to achieve better range and signal clarity when communicating over longer distances.
  6. Wireless Bridge Systems: For connecting two or more network segments without the need for physical cables, especially in scenarios where laying cables is impractical due to physical barriers or cost considerations.
  7. Remote Sensing and Telemetry: In agriculture, environmental monitoring, or industrial applications, 10 dBi antennas can be used to transmit data over long distances from remote sensors back to a central collection point.

The choice to use a 10 dBi antenna is often driven by the need for longer range and more directed signal propagation. However, the increased directionality means that precise alignment between the transmitting and receiving antennas becomes more critical. Additionally, the environment and regulatory constraints (like limits on transmission power) will also influence the effectiveness and suitability of using a 10 dBi antenna for a particular application.

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