5
Subject to change without notice
Important hints
I n t r o d u c t i o n
Introduction
Probe power is supplied directly from HAMEG
HM5010 / HM501 / HM550 Spectrum Analyzers.
In case different instruments are used, probe
power is supplied from an optional 6 V
DC
power
supply.
The connection of the probe to the spectrum
analyzer, oscilloscope or measurement receiver
is made via a supplied SMA- to N-connector cable
of approximately 1. meters length. This length
is generally sufficient for most measurements.
If for special reasons a longer cable is used, the
insertion loss of this cable must be added to the
output values at the higher frequencies.
For normal measurements, the probes are
connected to a spectrum analyzer. These instru-
ments generally have an input impedance of 50
Ohms. This impedance is the normal termination
impedance for the probes. If an oscilloscope
or measurement receiver with a different input
impedance is used, an additional 50 Ohms feed-
through termination must be used. If the probe
is not loaded with a 50 Ohm impedance, it is not
calibrated.
The different probes are used for different tests
since their electric characteristics are quite
different. The E-field probe is normally used at a
distance of 0.5 to 1.5meters from the RFI source.
The thereby observed frequencies are then further
localized near the source by use of the H-field
probe. The high impedance (Hi-Z) probe makes
further localization possible by directly contacting
the source and to judge the effectiveness of sup-
pression measures.
Because of its electrical characteristics, the E-
field probe is not intended to perform measure-
ments within an equipment or directly on parts
that are live. Electrical contact of the antenna
with live parts exceeding 0 VDC or + 10 dBm at
RF may cause damage to the built-in pre-amplifier.
These limits also apply to the Hi-Z probe; however,
electrical contact to parts that are below 0VDC
or + 10dBm are permitted.
Safety notice
Basically, it is not permissible to per-
form measurements on parts that are
live above 30V. Since a significant part
of the measurements are performed
on exposed parts, it is a prerequisi-
te that the user is familiar with any
potential electrical hazard. Under
no circumstances may the probes be
used on equipment that is not safety
grounded. When in doubt, a safety
isolation transformer must be used.
The probes may not be used to perform accurate
quantitative measurements. It is not possible to
relate the probe measurements directly to final
values of field strength in V/m necessary for
certification tests. The probe kit is intended as an
aid for developmental tests to obtain a qualitative
amplitude as a function of frequency. These values
are strongly influenced by the limiting conditions
of the measurement which may change as a func-
tion of frequency.
