ETS-Lindgren 7405 E & H Near Field Probe Set - Manual (Page 38)

38 Common Diagnostic Techniques www.ets-lindgren.com
 Differential mode data is generally well behaved. The amplitude
measured with the H-field probe will be significantly higher than that
measurement with the E-field probe. Also, the H-field will drop off at a
much faster rate than the E-field.
 Common mode measurements are generally less well behaved. Often
the best indicator is the relative amplitude. The E-field probe will have
a much higher reading than the H-field probe. The drop-off rate will be
faster when measured with the E-field probe. However, experience
shows that the E-field, being a high potential field, is much more
susceptible to perturbation. Often the reading will be sensitive to cable
placement and differences in the position of the person holding the
probe. This susceptibility to being perturbed can be a hint that the field
is coming from a high potential source.