Calculadora de Perda no Espaço Livre
Calcule a atenuação do sinal eletromagnético no espaço livre com base na frequência e distância.
Free Space Path Loss
120.0 dB
Free Space Path Loss vs Distance
Formula
## How Free Space Path Loss Works FSPL is the loss in signal strength as a radio wave spreads out over distance, assuming no obstacles. ### Formula **FSPL (dB) = 20 x log10(d_km) + 20 x log10(f_MHz) + 32.44** This comes from the Friis equation: FSPL = (4 x pi x d / lambda)^2, converted to decibels. ### Key Points - Doubling the distance adds 6 dB of loss - Doubling the frequency adds 6 dB of loss - This is the absolute minimum loss; real-world losses are higher due to obstacles, rain, and atmospheric absorption
Exemplo Resolvido
2.4 GHz Wi-Fi signal over 10 km in free space.
- 01FSPL = 20 x log10(10) + 20 x log10(2400) + 32.44
- 02= 20 + 67.60 + 32.44
- 03= 120.0 dB
Perguntas Frequentes
Why is FSPL so high even in free space?
FSPL accounts for the spreading of energy over the surface of an expanding sphere. It is geometric, not absorption loss.
Does free space path loss depend on power?
No. FSPL is independent of transmit power. It describes attenuation, not the received signal level.
When is the free space model appropriate?
For satellite links, point-to-point microwave, and as a baseline for more complex propagation models.
Aprender