*Question T3A05:
When using a directional antenna, how might your station be able to communicate with a distant repeater if buildings or obstructions are blocking the direct line of sight path?*  

*Correct Answer is  B: Try to find a path that reflects signals to the repeater*  

### AI Response: (may contain errors)  

When using a directional antenna to communicate with a distant repeater, obstructions like buildings can block the direct line of sight. The correct approach is to find a path that reflects signals to the repeater.

### Correct Answer: B - Try to find a path that reflects signals to the repeater

- **Explanation**: 
  - When direct line of sight is obstructed, signals can still reach the repeater by reflecting off surfaces such as buildings or hills. This is known as multipath propagation. By adjusting the antenna direction or position, you may find a reflective path that allows your signal to reach the repeater.

### Why the Other Choices are Incorrect:

- **A: Change from vertical to horizontal polarization**  
  - **Explanation**: Changing polarization may not help if the signal is blocked by obstructions. The polarization of the antenna should match that of the repeater, but simply changing it does not address the issue of line-of-sight blockage.

- **C: Try the long path**  
  - **Explanation**: The long path refers to a longer route for the signal, often involving the curvature of the Earth or ionospheric reflection. However, if there are obstructions in the direct path, the long path may not be effective either, especially if it does not provide a clear line of sight.

- **D: Increase the antenna SWR**  
  - **Explanation**: Increasing the Standing Wave Ratio (SWR) is not beneficial. A high SWR indicates poor matching between the antenna and the transmission line, which can lead to signal loss. The goal should be to minimize SWR for optimal performance, not increase it.

### Useful Rules of Thumb:

- **Multipath Propagation**: Signals can reflect off surfaces, allowing communication even when direct paths are blocked.
- **Antenna Positioning**: Experimenting with the angle and height of the antenna can help find a better reflective path.
- **SWR**: Aim for an SWR of 1.5:1 or lower for efficient transmission.

By understanding these concepts, you can effectively navigate communication challenges with directional antennas.