Yes, I wonder why! need to fix it for sure. Thanks for the feedback.

Hi, not really, I think perhaps you slightly missed the point. The point I wanted to make was, when making a measurement on a high speed board, coupling can affect your results. In other words, what you see on the scope may not be how the system behaves. Sometimes, in extreme cases, the person who performed the measurement can "fix" a problem by simply measuring the circuit, this is because the noise was bypassed by the engineer him/herself. This subject is quite complex, perhaps you can start from some basics, I am sure when you have seen enough issues in the filed, you will understand this a lot better.

Hi, the cable is part of the Tekbox near-field probe set, www.tekbox.com/product/tekbox-tbps01-emc-near-field-probes/, the cable is co-aixal SMA SMB one.

telonic.co.uk/product/tekbox-smbf-smam-75-rg316u-smb-female-to-sma-male-75cm-50ω-rf-cable/

Hi, definitely not the 1M ohm input, here, we are using a 50 ohm system in a sense that the transimisision line (the co-axial) is 50 ohm, and the RF current probe only works with 50 ohm. by selecting 1 M ohm, the characteristics of the RF monitoring probe will change completely and even place a negative impact on the signal you want to measure.

@@MachOneDesignEMCclear! Measurements always influence the system because the total sum of energy stays the same, except if it’s added like with an active probe.