*Question G9D02:
What is the feed point impedance of an end-fed half-wave antenna?*  

*Correct Answer is  D: Very high*  

### AI Response: (may contain errors)  

The feed point impedance of an end-fed half-wave antenna is considered to be very high. Here's a breakdown of why this is the case and why the other choices are incorrect.

### Correct Answer: Very High
- An end-fed half-wave antenna typically has a feed point impedance that can be in the range of several thousand ohms, often around 2000 to 5000 ohms. This high impedance is due to the antenna's design, where the feed point is located at one end of the half-wave length, resulting in a high voltage and low current at that point.

### Why Other Choices Are Incorrect:
- **A: Very Low**
  - A very low impedance would suggest a high current and low voltage, which is not characteristic of an end-fed half-wave antenna. Such antennas do not present low impedance at the feed point.

- **B: Approximately 50 ohms**
  - A feed point impedance of approximately 50 ohms is typical for center-fed dipole antennas, not for end-fed half-wave antennas. The end-fed design results in a much higher impedance.

- **C: Approximately 300 ohms**
  - While some antennas, like a folded dipole, may have an impedance around 300 ohms, this is not applicable to end-fed half-wave antennas. The impedance is significantly higher due to the end-fed configuration.

### Useful Formulas or Rules of Thumb:
- For a half-wave dipole antenna, the feed point impedance is generally around 73 ohms when fed at the center. However, for an end-fed half-wave antenna, the impedance is much higher due to the location of the feed point.
- A common rule of thumb is that the impedance increases as you move away from the center of the antenna towards the ends.

In summary, the end-fed half-wave antenna has a very high feed point impedance, making "Very high" the correct answer.