Seite 30
© Gigahertz Solutions GmbH
Made in Germany
within the specified tolerance. Nevertheless, the display should be checked fre-
quently in order to obtain the most accurate readings. In the case of very high and
short signal peaks, the holding capacity of the “Peak hold” function needs several
recurrences (less than a second) to fully load.
Quantitative Measurement:
Determination of Total High Frequency Pollution
As described in Getting Started, attach the LogPer
antenna to the
HF analyser.
Hold the HF analyser 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 an-
tenna, but should be
near the bottom end of the instrument.
In the area of a
local maximum,
the positioning of the HF analyser
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 di-
rection 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 analyser.
When scanning with the isotropic UBB27 aerial, it is sufficient to
move the instrument to see the field distortions effected by your
body.
Through
rotating the HF analyser
, with attached LogPer antenna,
around its longitudinal axis, determine the polarization plane of the
HF radiation. When using the UBB27 you only need to do this in
locations where radiation from directly below or above cannot be
ruled out (multi-storey buildings, town houses, etc)
Change the measurement position
and avoid measuring exclu-
sively in one spot, because that spot may have local or antenna-
specific cancellation effects.
Some manufacturers of field meters propagate the idea that the ef-
fective power density should be obtained by taking measurements of
all three axes and calculating the result. Most manufacturers of pro-
fessional testing equipment, however, do not share this view.
In general, it is well accepted that
exposure limit comparisons should be based on the maximum
value emitted from the direction of the strongest
radiation source. When using the UBB27, of course,
the directional component will not apply.
But the details of the situation need to be considered! For example,
if a 2.4-GHz telephone inside the house emits a similar level of micro-
waves as a nearby cellular phone base station outside the house, it
would be helpful to first turn off the 2.4-GHz telephone in the house.
Now measure the exposure level originating from the outside. After
having measured the emission of the 2.4-GHz telephone on its own,
the sum of both measurement values could be used for the exposure
Summary of Contents for HF59B
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