Gigahertz Solutions HF59B Bedienungsanleitung Seite 28

M a d e in G e r m a n y
interesting numerical value) can be determined. This can be achieved
as follows:
- By scanning "all directions" with the LogPer in order to locate the
direction from which the major HF emission(s) are originating. Move
your wrist right and left, or if necessary up and down, for instance in
apartment houses. For emission sources behind your back, turn
around and place your body behind the HF analyser. When scan-
ning with the isotropic UBB27 aerial, it is sufficient to move the in-
strument to the left and right, so as to avoid falsifications of the
measurement values by your body.
- By rotating the HF analyser around its longitudinal axis with the
attached LogPer antenna, so as to 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)
- By changing the measurement position, therefore avoiding to be
measuring exclusively in one spot, because that spot may have lo-
cal or antenna-specific cancellation effects.
Some manufacturers of field meters propagate the idea that the effec-
tive power density should be obtained by taking measurements of all
three axes and calculating the result. This is not the case when using
LogPer antennas as well as rod or telescopic antennas.
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.
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 as-
suming a far lower value of pollution than really existent, especially if
the specified downward tolerance of the meter is fully reached. How-
ever, 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 analys-
ers.
Cellular phone channel emissions vary with the load. The minimum HF
level occurs, when only the control channel operates. It is suggested
that measurements should be taken at different times during the day /
week in order to find out the times of highest traffic.
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In general, it is well accepted that
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