Made in Germany
10
© Gigahertz Solutions GmbH
the next finer range
5
.
The basic rule is: as coarse as necessary,
as fine as possible.
Setting
Signal Evaluation (“Signal“)
: The
peak HF radiation val-
ue
, not the average value, is regarded as the measurement of
critical “biological effects“ affecting the organism and to be com-
pared to recommended safety limits. This is the standard setting!
The
average value (“RMS“)
of pulsed signals is often only a very
small fraction of the peak value. Nonetheless it forms the basis of
most of the ”official“ safety limits regulations. Building biologists
consider this a trivialization.
„Peak hold“
(HF38B only) simplifies measurements of the total
exposure by retaining the highest readings for some time (it slowly
drops). Note of caution: Switch on ”softly“ to avoid switching
peaks, which then will be retained for some time simulating unre-
alistic power densities. If peaks are very short and very high the
holding capacity needs an instant until it is fully charged.
How to execute the measurements
Hold the HF analyzer with a
slightly outstretched arm,
your hand
at the rear of the instrument.
For a rough
first overview
it is sufficient to probe for areas of
higher levels of radiation simply by following the audio signals
walking through the rooms of interest, directing the analyser eve-
rywhere and rotating it.
Having identified the area of interest for a closer evaluation,
change the positioning of the instrument in order to analyse the
actual power flux density. This is done
by
pointing
in all directions including upwards and
downwards in flats to establish the main direction of the
incoming radiation,
by
rotating
the instrument around its longitudinal axis by
up to 90
°
to also find the plane of polarisation, and
by
shifting
the instrument in order to find the point of
maximum exposure and to avoid being trapped by local
cancellation effects.
It is generally accepted to use the highest reading in the room
for comparison with limit or recommended values.
Evaluating the different radio services
5
HF38B – „Range“: When switching from ‘Coarse’ to ‚Medium’ for very small
readings, it could happen, that the instrument tolerance of +/- 6 dB full range is
absorbed. In this worst case there may be a factor 4 between the displayed
numbers in ‚Coarse’ and ‚Medium’. Example: In ‘Medium’ you read 150
.
0
µ
W/m². If worst comes to worst ‘Coarse’ might show between 0
.
6 und 0
.
03
m
W/m² (instead of 0
.
15
m
W/m² which would be the correct value). However,
normally the differences shown will be much smaller. For comparing measure-
ments (e.g. ‘before’ and ‘after’) take the same range setting.
