*Question E9A06:
What is the effective radiated power (ERP) of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?*  

*Correct Answer is  A: 317 watts*  

### AI Response: (may contain errors)  

To calculate the Effective Radiated Power (ERP) of the repeater station, we need to account for the transmitter power, losses, and antenna gain. The formula for ERP is:

$$
ERP = P_T \times G_A \times 10^{\frac{L}{10}}
$$

where:
- $P_T$ = transmitter power in watts
- $G_A$ = antenna gain in linear scale
- $L$ = total losses in dB

### Step-by-step Calculation:

1. **Transmitter Power ($P_T$)**:  
   The transmitter power output is given as 200 watts.

2. **Antenna Gain ($G_A$)**:  
   The antenna gain is given as 10 dBd. To convert this to a linear scale, we use the formula:
   $$ 
   G_A = 10^{\frac{10 \text{ dB}}{10}} = 10 
   $$

3. **Total Losses ($L$)**:  
   We need to sum the losses from the feed line, duplexer, and circulator:
   - Feed line loss: 4 dB
   - Duplexer loss: 3.2 dB
   - Circulator loss: 0.8 dB

   Total losses:
   $$
   L = 4 + 3.2 + 0.8 = 8 \text{ dB}
   $$

4. **Calculating ERP**:  
   Now we can substitute these values into the ERP formula:
   $$
   ERP = 200 \times 10 \times 10^{\frac{-8}{10}} 
   $$
   Simplifying further:
   $$
   ERP = 2000 \times 10^{-0.8} 
   $$
   Using $10^{-0.8} \approx 0.1585$:
   $$
   ERP \approx 2000 \times 0.1585 \approx 317 \text{ watts}
   $$

### Why the Correct Answer is Correct:
- The calculated ERP of approximately 317 watts matches choice A. This value accurately reflects the transmitter power adjusted for the losses and the antenna gain.

### Why the Other Choices are Incorrect:
- **B: 2,000 watts**: This value does not account for the losses in the system. It assumes no losses, which is not realistic.
- **C: 126 watts**: This value is too low and does not reflect the correct calculations based on the given parameters.
- **D: 300 watts**: This is close but still incorrect; it does not accurately reflect the calculated ERP of 317 watts.

### Summary:
- The effective radiated power (ERP) is calculated by considering the transmitter power, losses, and antenna gain.
- The correct answer is 317 watts, as it accurately reflects the adjustments for losses and gain.