Gigahertz Solutions HFW59D, Руководство пользователя

Страница: 30 / 36

Made in Germany
28 © Gigahertz Solutions GmbH
may lead to far too high values if the meter was to be measuring in
the higher tolerance area.
Quantitative Measurement:
Identification of HF inflow
As a first step eliminate sources from within the same room (e.g.
wireless LAN). Once this is completed, the remaining radiation will
originate from outside. For remedial shielding it is important to iden-
tify those areas of all walls (including doors, windows and window
frames!), ceiling and floor, which are penetrated by the radiation. To
do this one should not stand in the centre of the room, measuring in
all directions from there, but monitor the permeable areas with the
antenna (LogPer) directed and positioned close to the wall
4
. That is
because the antenna lobe widens with increasing frequency. In ad-
dition reflections and cancellations inside rooms make it difficult
and often impossible to locate the “leaks” accurately. See the illus-
trating sketch below!
wall
antenna
wall
antenna
potentiell
durchlässiger
Bereich
wrong!
right!
potentially HF-permeable
part of the wall
The uncertainty of localization with HF-antennas
The shielding itself should be defined and surveyed by a specialist
and in any case the area covered by it should be much larger than
the leak.
4
Please note: In this position the readings on the LCD only indicate relative highs
and lows that cannot be interpreted in absolute terms.