*Question E9A07:
What is the effective isotropic radiated power (EIRP) of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?*  

*Correct Answer is  B: 252 watts*  

### AI Response: (may contain errors)  

To calculate the effective isotropic radiated power (EIRP) of the repeater station, we need to account for the transmitter power, feed line loss, duplexer loss, circulator loss, and antenna gain. The formula for EIRP is:

$$
EIRP = P_T \times 10^{\left(\frac{G_A - L_F - L_D - L_C}{10}\right)}
$$

where:
- $P_T$ = transmitter power in watts (200 watts)
- $G_A$ = antenna gain in dBi (7 dBi)
- $L_F$ = feed line loss in dB (2 dB)
- $L_D$ = duplexer loss in dB (2.8 dB)
- $L_C$ = circulator loss in dB (1.2 dB)

**Step-by-step Calculation:**

1. **Calculate Total Losses:**
   - Total losses = $L_F + L_D + L_C = 2 + 2.8 + 1.2 = 6$ dB

2. **Calculate Net Gain:**
   - Net gain = $G_A - \text{Total losses} = 7 - 6 = 1$ dB

3. **Convert Net Gain to Linear Scale:**
   - Linear gain = $10^{\left(\frac{1}{10}\right)} \approx 1.26$

4. **Calculate EIRP:**
   - $EIRP = 200 \times 1.26 \approx 252$ watts

**Explanation of Choices:**

- **A: 159 watts**  
  This choice is incorrect because it likely results from a miscalculation of the net gain or incorrect conversion from dB to linear scale.

- **B: 252 watts**  
  This is the correct answer, as shown by the calculation above.

- **C: 632 watts**  
  This choice is incorrect and may result from incorrectly adding gains instead of subtracting losses.

- **D: 63.2 watts**  
  This choice is incorrect and likely results from a significant error in the calculation, such as using the wrong formula or misapplying the dB conversion.

By following the steps and using the correct formula, you can determine that the EIRP is 252 watts, making choice B the correct answer.