Permanently Low Display Values - Gigahertz Solutions HF W 35C Instruction Manual

Digital High Frequency Analyser HF W 35C

Permanently low display values?

Fortunately, exposures in the frequency
range of the HFW35C are not yet wide-
spread. Therefore, we have often been asked
whether the device does in fact work, as it
rarely ever shows any values. In the following
please find answers to frequently asked
questions:
"The HFW35C only indicates very low
measuring values"
Answer:
Naturally, the radar and directional radio fre-
quencies within the frequency range of the
HFW35C will only be found regionally. At
present, the components for the upper
WLAN band (from 5 to 6 GHz) are still difficult
to obtain, so you will only encounter selective
exposures in this frequency range. The Wi-
MAX network (from 3 to 5 GHz) is only active
in some testing locations, its extension all
over the country is, however, expected to be
accomplished within the coming two years.
Therefore, for the time being, the HFW35C
can be considered as a device enabling to
exclude potential stronger exposures caused
by these sources at the respective site. This
already is an important information.
The presently most frequently measured ap-
pliances are Bluetooth appliances found at
the lowest end of the involved frequency
range... Questions related to this field:
"Even when transmitting data with my
notebook, only low values are shown on
the display"
Answer:
© Gigahertz Solutions GmbH, 90579 Langenzenn, Germany
Thanks to the integrated transmitting power
control, the notebook won't draw more
power than needed for its communication
with the remote station. However, if you
measure within splitting distance to a note-
book just transmitting data wireless, you will
obtain values, at least in the finer measuring
range.
"No measurement values obtained, even
directly next to my WLAN/Bluetooth-
compatible notebook..."
"...although the display indicates: 'search-
ing wireless connections'"
Answer:
While searching a network, the notebook is
basically not transmitting itself, so obviously
no measurements can be obtained.
"...although my notebook shows various
networks with good reception"
Answer:
A notebook has no problems with the recep-
tion, even if the signal strength is a factor
1000 or more below the lowest display value
of the measuring device or below the build-
ing biology recommendations.
"In the finer measuring range, the HFW
never shows values beyond 0.3 to 0.5
µW/m² (with or without antenna)"
Answer:
This is the residual noise of the device. It
would be easy to wire the display in such a
way that it would approach zero as soon as
only little values are shown, thus suggesting
higher precision (paradoxically, the producer
himself even recommends to do so!). How-
ever, we do not consider this useful, and pre-
Revision 4.7 (October 2007)
fer to indicate the residual noise the way it is.
Yet, if measurements without antenna reach
values beyond 0.9 µW/m² within the fine
measurement range (or 9 within the coarse
measurement range), you should return the
device for investigation, as this does no
longer correspond to the specifications.
Simple testing method:
Take measurements only few meters away
from an active point of access (e.g. "DSL-
WLAN-router). Its "heartbeat",
known "tac-tac-tac...", will be clearly audi-
ble, and the corresponding pulsed radiation
measurable. If this works out, errors can be
(almost) excluded, even for the highest fre-
quency range. At least we have not yet had a
frequency selected defect of this kind in all
the years of producing HF devices.
THE solution: a pre-amplifier!
Based on the statements in the chapter "Lim-
iting values, recommendations and precau-
tions" about the extreme effects of WLAN
signals on the human biology, an increased
range appears to make sense. There is a pre-
amplifier available for the amplification by a
factor of 100 (HV20_2400G10). Please note:
Always measure in the "Pulse"-mode
when applying the pre-amplilfier.
the well
Page 10