Gigahertz Solutions HF59B Bedienungsanleitung Seite 33

assessment. (This is necessary only when using the LogPer aerial.
The isotropic UBB27 does this in a single measurement).
There is no "official regulation" nor clearly defined testing protocol,
because according to national standards setting institutions, as de-
scribed earlier, quantitatively reliable, targeted and reproducible
measurements are only possible under "free field conditions" but not
in indoor environments.
To be on the safe side when comparing limit values, multiply the dis-
played value by 2 and use the result as basis for the comparison. This
method is often used by the building biology professionals to avoid
assuming a far lower value of pollution than really existent, especially
if the specified downward tolerance of the meter is fully reached.
However, please be aware of the fact that the so calculated values
may be far too high should the upward tolerance be fully reached.
This measurement uncertainty factor appears to be very high at first, but becomes realistic
when taking into account that the same factor is applied even for professional sprectrum ana-
lysers.
Cellular phone channel emissions vary with the load. The minimum
HF level occurs, when only the control channel operates. It is sug-
gested that measurements should be taken at different times during
the day / week in order to find out the times of highest traffic.
Evaluating the different radio services
Please use "Peak hold" and "VBW standard
The HF59B displays show the sum of the total power density within
the frequency range of the most common digital radio services. This
means for the often dominating sources GSM, PCT/DECT or the wire-
less LAN beacon signal (standby-"rattling"), as well as analogue
sources: Simply take the readings and compare them to the building
biology standard values!
To be able to evaluate the different radio standards, transmission and
modulation patterns with one single measurement technology, com-
pensation is required. The following approach is recommended:
CDMA, UMTS/3G, LTE/4G, WiMAX, DVB, Wireless LAN
:
transmission
The modulation of these high-speed services includes high, needle-
like peaks compared to the average power transmitted. Such signals
are referred to as "high crest factor" signals.
Measure these signals for 1 or 2 minutes (with peak hold) by slightly
panning the meter pointing to the direction of the main source. For
the assessment of the peak values of such signals (including the crest
factors) keep the standard setting "Peak hold" and "VBW standard"
11
The VBW of your HF-Analyser is so chosen, that "mistaken additions" cannot oc-
cur, even if multiple GSM traffic channels are fully used.
12
Ideally one would keep the setting "RMS", as the utilized circuitry by its nature
ensures the correct display of RMS values independently of the signal's crest fac-
© Gigahertz Solutions GmbH
Made in Germany
11
" as standard settings.
during full data
12
.
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