Gigahertz Solutions HF58B Instruction Manual page 8

Digital High Frequency Analyser HF58B
ated with pulse-modulated HF radiation since
through the "averaging" of steep HF pulses,
HF radiation exposure can be underrated up
to a factor of 100, such as in 2.4-GHz cord-
less phones.
Signal Evaluation – Peak Hold
Many measuring technicians work with the
function "Signal Evaluation" "Peak Hold". In
"peak hold" mode the highest value of the
signal within a defined time span can be ob-
tained /"collected".
Clear the display with the push button "Reset
Peak Hold". While this button is pushed and
held the readings are regular "Peak" read-
ings. To start a new "Peak Hold" measure-
ment, push and hold this reset button for 2
seconds, then release it.
In everyday measurement practice this func-
tion has great value. The peak value is re-
lated to the actual signal situation. This is
important because the immission situation
can change rapidly with time, direction of the
radiation, polarization, and the points of
measurements.. The "Peak Hold" mode
guarantees that you do not miss single
peaks.
The tone signal works independently of data
collection in the peak hold mode. Its sound is
proportional to the actual value measured. It
helps to identify the location, direction, and
polarization of the maximum field strength.
You can chose the (inevitable) droop rate, at
which the held peak value decreases over
time. Set the switch below the signal evalua-
tion switch (recessed in the casing) to "Slow"
or "Fast". In "Slow" mode it takes about 20
© Gigahertz Solutions GmbH, 90579 Langenzenn, Germany
minutes to run out of tolerance, but in order
to get an accurate reading the display should
be checked frequently. If very short signal
peaks occur then the holding capacity of the
function needs some recurrences to load
fully.
Revision 4.5 (December 2006)
Quantitative Measurement:
Determination of Total High Frequency
Pollution
As described in Getting Started, attach the
LogPer antenna to the HF analyzer. Hold
the HF analyzer with a slightly outstretched
arm because objects (mass) directly behind
it "like yourself", have effects on the testing
result. Your hand should not get too close to
the antenna, but should be near the bottom
end of the instrument.
In the area of a local maximum, the posi-
tioning of the HF analyzer should be changed
until the highest power density (the most im-
portant measurement value) can be located.
This can be achieved as follows:
- When scanning "all directions" with the
LogPer to locate the direction from which
the major HF emission(s) originate, move
your wrist right and left. For emission
sources behind your back, you have to
turn around and place your body behind
the HF analyzer.
- Through rotating the HF analyzer, with at-
tached LogPer antenna, around its longi-
tudinal axis, determine the polarization
plane of the HF radiation.
- Change the measurement position and
avoid measuring exclusively in one spot..
because that spot may have local or an-
tenna-specific cancellation effects.
Some manufacturers of field meters propa-
gate the idea that the effective power density
should be obtained by taking measurements
of all three axes and calculating the result.
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