*Question T4A05:
Where should an RF power meter be installed?*  

*Correct Answer is  A: In the feed line, between the transmitter and antenna*  

### AI Response: (may contain errors)  

To determine where an RF power meter should be installed, let's analyze the options:

### Correct Answer: A - In the feed line, between the transmitter and antenna

- **Explanation**: 
  - Installing the RF power meter in the feed line allows you to measure the actual power being transmitted to the antenna. This is crucial for ensuring that the transmitter is operating efficiently and that the antenna is properly matched to the transmitter's output. 
  - By measuring the power at this point, you can also identify any losses in the feed line or issues with the antenna system.

### Why the Other Choices are Incorrect:

- **B: At the power supply output**  
  - **Explanation**: Measuring power at the power supply output does not provide an accurate representation of the RF power being transmitted. The power supply output measures DC power, not RF power, and does not account for losses or gains in the transmitter or feed line.

- **C: In parallel with the push-to-talk line and the antenna**  
  - **Explanation**: This setup is not appropriate for measuring RF power. The push-to-talk line is a control line, not a power line, and placing a power meter in parallel with it would not yield any meaningful RF power measurements.

- **D: In the power supply cable, as close as possible to the radio**  
  - **Explanation**: Similar to option B, measuring power in the power supply cable only provides information about the DC power being supplied to the radio. It does not reflect the RF power output, which is what the RF power meter is designed to measure.

### Summary

- The RF power meter should be installed in the feed line to accurately measure the RF power being transmitted to the antenna.
- This ensures that you can monitor the performance of your transmitter and antenna system effectively.

### Useful Rule of Thumb

- Always measure RF power at the point where it is delivered to the antenna to get the most accurate assessment of your system's performance.