- vCommons Home
- Free-Space Path Loss (using frequency)

# Free-Space Path Loss (using frequency)

DavidC.Free-Space Path Loss (using frequency)

The **Free-space Path Loss (FSPL)** calculator computes the loss of signal strength on a line-of-sight path which has no obstacles or other disturbances based on the distance (**d**) and the frequency (**f**) of the signal.

**INSTRUCTIONS:** Choose the preferred units and enter the following:

- (
**d**) This is the distance between receivers. - (
**f**) This is the frequency of the signal.

**Free-Space Path Loss:** The calculator returns the loss in dB. However, this can be automatically converted to a real or percent via the pull-down menu.

##### Related Calculators

- Free-Space Path Loss (wavelength): This computes the FSPL as function of wavelength instead of frequency.
- Free-Space Path Loss (using frequency)
- Fiber Optic Cable dB Loss Budget Calculator:
- Compute Frequency from Wavelength
- Compute Wavelength from Frequency

#### General Information

The formula for the Free-Space Path Loss using frequency is:

FSPL = ` ((4 pi * d*f)/c)^2`

where:

- FSPL is the Free-space path loss
- d is the distance between receivers.
- f is the frequency of the signal.

This equation uses the frequency and the constant for speed of light to calculate the FSPL.

This equation is only accurate at a distance from the transmitter where spherical spreading can be assumed. This equation is not accurate for short distances.

**Free-Space Path Loss (using frequency)**, references 1 equation/constant.

**Equations and Constants **