*Question G0A09:
What type of instrument can be used to accurately measure an RF field strength?*  

*Correct Answer is  B: A calibrated field strength meter with a calibrated antenna*  

### AI Response: (may contain errors)  

To accurately measure an RF field strength, the best choice is:

**Correct Answer: B: A calibrated field strength meter with a calibrated antenna**

### Explanation of the Correct Answer:
- A calibrated field strength meter is specifically designed to measure the strength of RF fields. 
- It provides accurate readings because it is calibrated to account for various factors that can affect measurements, such as frequency and environmental conditions.
- The use of a calibrated antenna ensures that the measurements are consistent and reliable across different frequencies.

### Why the Other Choices are Incorrect:
- **A: A receiver with digital signal processing (DSP) noise reduction**
  - While DSP can improve the quality of received signals, it does not measure field strength directly. It processes signals to reduce noise but does not provide a quantitative measurement of RF field strength.

- **C: An SWR meter with a peak-reading function**
  - An SWR (Standing Wave Ratio) meter measures the efficiency of power transfer from the transmitter to the antenna, not the actual RF field strength. It indicates how well the antenna is matched to the transmission line but does not provide a direct measurement of field strength.

- **D: An oscilloscope with a high-stability crystal marker generator**
  - An oscilloscope can visualize waveforms and measure voltage levels, but it is not designed to measure RF field strength. The crystal marker generator helps in frequency stability but does not contribute to field strength measurement.

### Summary:
For accurate RF field strength measurements, a calibrated field strength meter with a calibrated antenna is essential. Other instruments may provide useful information but do not directly measure field strength.