# Antenna Range Calculator

This tool computes the maximum range that can be achieved in a communication system. The system includes a transmitter, transmit antenna, receiver and receive antenna.

To calculate the max distance, enter the following:

• Frequency of operation (Hz/KHz/MHz/GHz)
• Transmit Power (dBm)
• Transmit Antenna Gain (dBi)
• Total Cable and Other Losses (dB)

## Formula

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

FSPL = 20*Log10(d) + 20*Log10(f) + Lc + 20*Log10(4π/c) – GTx – GRx

## Example Range Calculation

At a frequency of 2450 MHz (ISM band) and transmit power of +20 dBm, let’s take a look at the range of a Wi-Fi system in free space.

With a receive sensitivity of -90 dBm, transmit and receive antenna gain of 0 dBi, and 0 dB cable loss, the maximum range is 3.1 km or 1.9 miles.

Important to remember that this calculation is outdoors and free space which is an ideal condition.

Assuming indoor conditions, using our indoor Wi-Fi range calculator the same level of received signal is achieved at only 55 meters. A much smaller range. This is to be expected as signals are attenuated more indoors than in free space.

## How to use the Calculator

### Frequency of operation

This is the frequency at which the communication system operates. The range is higher at lower frequencies, so entering the highest operating frequency will give you an upper limit on the achievable range. In the case of L-band for instance, use f = 2.1 GHz.

### Transmit Power

This is the power at the output connector of the transmitter. It is usually specified in dBm. If specified in Watt, use this calculator to convert to dBm.

### Transmit Antenna Gain

This depends on the type of antenna used and is expressed in dBi. It can be calculated from the Antenna Factor and frequency of operation.