EIRP Calculator

Transmitter Power (\( P_t \)):

Antenna Gain (\( G \)):

Losses (\( L \)):

1. What is an EIRP Calculator?

Definition: This calculator determines the Effective Isotropic Radiated Power (EIRP), which is the power that would be radiated by an isotropic antenna to produce the same signal strength in a given direction as the actual antenna system, accounting for transmitter power, antenna gain, and losses.

Purpose: It helps RF engineers and system designers evaluate the effective power radiated by an antenna system, which is critical for assessing signal coverage, link budgets, and compliance with regulatory limits in applications like wireless communication, satellite systems, and radar.

2. How Does the Calculator Work?

The calculator uses the following formula to compute EIRP:

EIRP (dBm): \[ \text{EIRP (dBm)} = P_t + G - L \]

Where:

\( \text{EIRP} \): Effective Isotropic Radiated Power in dBm
\( P_t \): Transmitter power in dBm
\( G \): Antenna gain in dBi
\( L \): Total losses (e.g., cable losses, connector losses) in dB

Unit Conversions:

Input Power (\( P_t \)):
1 mW = \( 10^{\text{dBm}/10} \) dBm
1 watt = \( 10 \log_{10}(1000) \) dBm
1 dBW = dBm - 30
Output EIRP:
1 dBW = dBm - 30
1 watt = \( 10^{\text{dBm}/10} \times 10^{-3} \)
1 mW = \( 10^{\text{dBm}/10} \)

Steps:

Enter the transmitter power \( P_t \), antenna gain \( G \), and total losses \( L \), selecting the appropriate unit for \( P_t \) (watts, mW, dBm, or dBW).
Click "Calculate" to compute the EIRP.
The result is initially displayed in dBm.
Select a different unit for EIRP (dBm, dBW, watts, or mW) from the dropdown after the result to convert the displayed value.

3. Importance of EIRP Calculation

Calculating EIRP is essential for:

Signal Coverage: Determines the effective radiated power, which impacts the range and coverage area of a wireless system.
Link Budget Analysis: Provides a key parameter for calculating signal strength in communication systems, ensuring reliable connectivity.
Regulatory Compliance: Ensures that the radiated power complies with regulatory limits set by authorities like the FCC or ITU, avoiding interference with other systems.

4. Using the Calculator

Examples:

Example 1: \( P_t = 100 \) dBm, \( G = 30 \) dBi, \( L = 2 \) dB, Result in dBm
- \( \text{EIRP} = 100 + 30 - 2 = 128 \, \text{dBm} \)
Example 2: \( P_t = 1000 \) mW, \( G = 30 \) dBi, \( L = 2 \) dB, Result in dBW
- Convert: \( P_t = 10 \log_{10}(1000) = 30 \, \text{dBm} \)
- \( \text{EIRP} = 30 + 30 - 2 = 58 \, \text{dBm} \)
- Result in dBW: \( 58 - 30 = 28 \, \text{dBW} \)
Example 3: \( P_t = 0 \) dBW, \( G = 30 \) dBi, \( L = 2 \) dB, Result in watts
- Convert: \( P_t = 0 + 30 = 30 \, \text{dBm} \)
- \( \text{EIRP} = 30 + 30 - 2 = 58 \, \text{dBm} \)
- Result in watts: \( 10^{58/10} \times 10^{-3} = 10^{5.8} \times 10^{-3} \approx 630957.3 \, \text{W} \)

5. Frequently Asked Questions (FAQ)

Q: What is EIRP and why is it important?
A: EIRP (Effective Isotropic Radiated Power) is the power that would be radiated by an isotropic antenna to produce the same signal strength as the actual antenna system in a given direction. It’s important for evaluating signal coverage, link budgets, and ensuring compliance with regulatory power limits.

Q: How do losses affect EIRP?
A: Losses (e.g., cable losses, connector losses) reduce the EIRP by subtracting from the total power. Higher losses result in a lower EIRP, which can decrease the effective range of the system.

Q: What factors should be considered in real-world EIRP calculations?
A: Real-world EIRP calculations should account for additional factors like environmental losses (e.g., atmospheric absorption), antenna efficiency, and polarization mismatch, which can affect the actual radiated power.