ETS-Lindgren 7405 E & H Near Field Probe Set - Manual (Page 17)

www.ets-lindgren.com Operation 17
 How closely you want to define the location of the source: Choose
the probe that gets as close to the signal source as required. Select a
large probe and begin outside a unit, then move closer to the source
and switch to smaller probes to identify the location of the source.
For example, the smallest probes should allow you to determine
exactly which circuit on a printed circuit board is radiating. This kind of
refinement provides the ability to stop the radiation at the source rather
than shielding an entire unit.
Preamplifier Use
The optional preamplifier increases the sensitivity of your test system. The
preamplifier is connected to the input of the signal analyzing device, and the
coaxial cable from the probe is connected to the preamplifier. A switch on the
preamplifier activates power to the unit; when power is activated, a panel light
illuminates.
The preamplifier is powered by a wall-mounted DC power supply. Both 115 VAC
and 230 VAC models are available. The preamplifier includes a standard
DC power connector.