*Question G4E03:
Which of the following direct, fused power connections would be the best for a 100-watt HF mobile installation?*  

*Correct Answer is  A: To the battery using heavy-gauge wire*  

### AI Response: (may contain errors)  

To determine the best direct, fused power connection for a 100-watt HF mobile installation, let's analyze the options:

### Correct Answer: A - To the battery using heavy-gauge wire

1. **Why this is correct:**
   - **Voltage Drop:** Heavy-gauge wire minimizes voltage drop over the distance from the battery to the radio. This is crucial for maintaining the performance of the radio, especially under load.
   - **Current Capacity:** A 100-watt HF radio typically draws around 8-10 amps (using $P = V \times I$, where $P$ is power in watts and $V$ is voltage). Heavy-gauge wire can safely handle this current without overheating.
   - **Direct Connection:** Connecting directly to the battery ensures a stable power source, as the battery can provide the necessary current without the fluctuations that might occur if connected to the alternator.

### Why the other choices are incorrect:

2. **Choice B: To the alternator or generator using heavy-gauge wire**
   - **Alternator Fluctuations:** The alternator's output can vary with engine speed, leading to potential voltage fluctuations that can affect radio performance.
   - **Distance Issues:** The connection to the alternator may be farther away than the battery, increasing the risk of voltage drop.

3. **Choice C: To the battery using insulated heavy-duty balanced transmission line**
   - **Inappropriate Use:** Balanced transmission lines are designed for RF signals, not for DC power connections. Using them for power can lead to inefficiencies and potential safety hazards.
   - **Not Suitable for Power:** They are not intended to carry the DC current required for powering a radio.

4. **Choice D: To the alternator or generator using insulated heavy-duty balanced transmission line**
   - **Combination of Issues:** This option combines the problems of both B and C. It is not suitable for DC power and is subject to the voltage fluctuations of the alternator.

### Useful Rules of Thumb:
- **Wire Gauge:** Use the American Wire Gauge (AWG) system to select appropriate wire sizes. For 10 amps, a minimum of 16 AWG is recommended, but 14 AWG or lower (thicker wire) is better for longer runs.
- **Fusing:** Always include a fuse close to the battery to protect against short circuits. A fuse rated slightly above the expected current draw (e.g., 10-15 amps for a 100-watt radio) is advisable.

In summary, the best choice for a 100-watt HF mobile installation is to connect directly to the battery using heavy-gauge wire to ensure stable power delivery and minimize voltage drop.