| Playing with a snap-on ferrite | |
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This little test has been made with a 6.5mm inside diameter ferrite like the one shown on the left picture. The value of its material is unknown. Since a long time i have used those snap-on ferrite clamp as a RF choke to try to mitigate the common mode currents (CMC) on my station's cables. (USB cables, control cables, power lines, command cables and coaxial cables). |
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Make sure you have calibrated your NanoVNA for the 3 MHz to 30 MHz range |
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Setup for measurments The ferrite is connected to the 'PORT_1' and 'PORT_2' of the NanoVNA-F as follow:. 
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Setup of the NanoVNA-F V2 To activate the various menus, click on the right side of the VNA display and select the following values: |
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- STIMULUS / START / 3 M - STIMULUS / STOP / 30 M - DISPLAY / TRACE / TRACE_0 (only) - DISPLAY / CHANNEL = S21 (THRU) - DISPLAY / FORMAT / LOGMAG - MARKER / SELECT / MARKER 1 |
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Results:
For 1 pass through the attenuation is 4.8 db at 15 MHz For 2 pass through the attenuation is 13.8 db at 15 MHz For 3 pass through the attenuation is 19.2 db at 15 MHz For 4 pass through the attenuation is 25.0 db at 15 MHz |
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