Received Power Calculator Software

Friis Transmission Equation:

\[ P_r = P_t \times G_t \times G_r \times \left( \frac{\lambda}{4 \pi d} \right)^2 \]

Transmitted Power (P_t):

Transmit Gain (G_t):

Receive Gain (G_r):

Wavelength (λ):

Distance (d):

Received Power (P_r):

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1. What is the Friis Transmission Equation?

The Friis transmission equation is a fundamental formula in telecommunications that calculates the power received by an antenna from another antenna some distance away. It's essential for wireless communication system design and link budget analysis.

2. How Does the Calculator Work?

The calculator uses the Friis transmission equation:

\[ P_r = P_t \times G_t \times G_r \times \left( \frac{\lambda}{4 \pi d} \right)^2 \]

Where:

\( P_r \) — Received power (W)
\( P_t \) — Transmitted power (W)
\( G_t \) — Transmit antenna gain (dB)
\( G_r \) — Receive antenna gain (dB)
\( \lambda \) — Wavelength (m)
\( d \) — Distance between antennas (m)

Explanation: The equation accounts for free-space path loss and the gains of both transmitting and receiving antennas.

3. Importance of Received Power Calculation

Details: Accurate received power calculation is crucial for designing reliable wireless communication systems, determining signal coverage areas, and ensuring proper signal-to-noise ratios for effective data transmission.

4. Using the Calculator

Tips: Enter all values in the specified units. Transmitted power and distance must be positive values. Antenna gains are entered in dB and converted to linear scale internally.

5. Frequently Asked Questions (FAQ)

Q1: What is free-space path loss?
A: Free-space path loss is the attenuation of radio signal strength as it propagates through free space, proportional to the square of the distance and the square of the frequency.

Q2: How are dB gains converted to linear scale?
A: dB gains are converted using the formula: \( G_{linear} = 10^{(G_{dB}/10)} \)

Q3: What are typical values for antenna gains?
A: Typical values range from -3 dB to 20+ dB, depending on antenna type and design. Isotropic antennas have 0 dBi gain.

Q4: Does this equation account for real-world obstacles?
A: No, the Friis equation assumes free-space propagation without obstacles, reflection, or diffraction. Real-world calculations may require additional loss factors.

Q5: How does wavelength relate to frequency?
A: Wavelength (λ) = speed of light (c) / frequency (f), where c ≈ 3×10⁸ m/s. So λ = 300/f for f in MHz, or λ = 0.3/f for f in GHz.