*Question G4E04:
Why should DC power for a 100-watt HF transceiver not be supplied by a vehicle’s auxiliary power socket?*  

*Correct Answer is  B: The socket’s wiring may be inadequate for the current drawn by the transceiver*  

### AI Response: (may contain errors)  

The correct answer to why DC power for a 100-watt HF transceiver should not be supplied by a vehicle’s auxiliary power socket is:

**B: The socket’s wiring may be inadequate for the current drawn by the transceiver.**

### Explanation of the Correct Answer:
- **Current Draw**: A 100-watt HF transceiver typically draws significant current, especially during transmission. The current can be calculated using the formula:
  
  $$I = \frac{P}{V}$$

  where:
  - $I$ = current in amperes (A)
  - $P$ = power in watts (W)
  - $V$ = voltage in volts (V)

  For a 12-volt system, the current draw would be:

  $$I = \frac{100 \text{ W}}{12 \text{ V}} \approx 8.33 \text{ A}$$

- **Auxiliary Socket Limitations**: Most vehicle auxiliary power sockets (cigarette lighter sockets) are typically rated for 10-15 A. If the wiring is not designed to handle the high current, it can lead to overheating, voltage drop, or even a fire hazard.

### Explanation of Incorrect Answers:
- **A: The socket is not wired with an RF-shielded power cable**  
  - While RF shielding is important for preventing interference, the primary concern with power delivery is the current capacity of the wiring, not the shielding.

- **C: The DC polarity of the socket is reversed from the polarity of modern HF transceivers**  
  - Most modern HF transceivers are designed to work with standard automotive DC polarity (positive on the center pin). Reversed polarity would typically damage the equipment, but this is not the main issue with using an auxiliary socket.

- **D: Drawing more than 50 watts from this socket could cause the engine to overheat**  
  - This statement is misleading. The engine itself does not overheat from the power drawn by accessories; rather, it is the wiring and the socket that may overheat if they are not rated for the current. The engine's cooling system is separate from the electrical system.

### Summary:
When using a vehicle's auxiliary power socket for a 100-watt HF transceiver, the main concern is ensuring that the wiring can handle the current draw safely. Always check the specifications of the socket and consider using a direct connection to the battery with appropriate fuses for high-power devices.