#379: How to measure coax loss using a NanoVNA
2 min read
4 months ago
Published on Apr 21, 2024
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Table of Contents
Step-by-Step Tutorial: How to Measure Coax Loss Using a NanoVNA
1. Introduction to Coax Cables:
- The video discusses measuring the loss of coax cables used for portable HF amateur radio operation below 30 MHz.
- The presenter compares different types of coax cables like RG316 and RG174 for HF QRP operation.
2. Prepare for Testing:
- Gather the necessary equipment: NanoVNA, coax cables (RG316, RG174), SMA to BNC adapters, open, short, and load calibration standards.
3. Calibration Process:
- Set the frequency range for testing, typically up to 30 MHz.
- Calibrate the NanoVNA by connecting open, short, and load calibration standards using SMA connectors.
- Use high-quality BNC to SMA adapters for calibration.
4. Perform Measurements:
- Connect the coax cables to be tested to the NanoVNA.
- Measure the attenuation (S21) of each coax cable at frequencies commonly used for portable operation (e.g., 40m, 20m, 10m).
5. Analyze Results:
- Compare the measured losses of different coax cables (RG316, RG174) at different frequencies.
- Note any differences in performance, such as the presence of a common mode choke affecting the results.
6. Interpretation of Results:
- Evaluate the losses of each coax cable at various HF bands.
- Consider factors like cable condition, connectors' cleanliness, and potential damage affecting the results.
7. Conclusion and Recommendations:
- Summarize the findings and compare the measured losses of the tested coax cables.
- Assess the suitability of each coax cable for portable HF operation based on the measured losses.
8. Appreciation and Bonus Content:
- Acknowledge any contributors or viewers who have provided support or gifts related to the testing equipment.
- Express gratitude for the audience's support and interest in the content.
By following these steps, you can effectively measure the loss of coax cables using a NanoVNA for amateur radio operations below 30 MHz.