*Question T7B05:
How can fundamental overload of a non-amateur radio or TV receiver by an amateur signal be reduced or eliminated?*  

*Correct Answer is  A: Block the amateur signal with a filter at the antenna input of the affected receiver*  

### AI Response: (may contain errors)  

To address the question of how to reduce or eliminate fundamental overload of a non-amateur radio or TV receiver by an amateur signal, let's analyze the options provided.

### Correct Answer: 
**A: Block the amateur signal with a filter at the antenna input of the affected receiver.**

- **Explanation**: 
  - Fundamental overload occurs when a strong signal from an amateur radio transmitter interferes with the normal operation of a nearby non-amateur receiver. By placing a filter at the antenna input of the affected receiver, you can attenuate the amateur signal before it reaches the receiver's front end. This helps prevent the receiver from being overloaded by the strong signal, allowing it to function properly without distortion or interference.

### Why the Other Choices are Incorrect:

**B: Block the interfering signal with a filter on the amateur transmitter.**
- **Explanation**: 
  - While filtering on the transmitter can help reduce unwanted harmonics or spurious emissions, it does not address the issue of the receiver being overloaded by the fundamental frequency of the amateur signal. The receiver is still exposed to the strong signal, which can cause overload.

**C: Switch the transmitter from FM to SSB.**
- **Explanation**: 
  - Changing the mode from FM (Frequency Modulation) to SSB (Single Sideband) does not inherently reduce the strength of the signal being transmitted. In fact, SSB can be more efficient in terms of bandwidth, but it does not solve the problem of fundamental overload at the receiver. The signal strength remains the same, and the receiver can still be overloaded.

**D: Switch the transmitter to a narrow-band mode.**
- **Explanation**: 
  - While narrow-band modes can reduce the bandwidth of the transmitted signal, they do not reduce the power level of the signal itself. The fundamental frequency can still cause overload in the receiver, as the issue is primarily related to signal strength rather than bandwidth.

### Summary:
- The most effective solution to prevent fundamental overload is to use a filter at the antenna input of the affected receiver (Choice A). This method directly addresses the problem by reducing the strength of the interfering amateur signal before it can affect the receiver's performance. 

### Useful Rule of Thumb:
- **Filtering**: Always consider using filters to manage interference, especially when dealing with strong signals that can cause overload in sensitive receivers.