User manual

Digitaler Hochfrequenz Analyser HF38B
© Gigahertz Solutions GmbH, D-90579 Langenzenn Revision 2.3 Page 5
Preparations Prior to Testing
Check the RF analyzer and its antenna by
following the instrunctions under „Getting
Started.“
Connecting the Antenna
Screw the angle connector of the antenna
connection into the uppermost right socket
of the RF analyzer. It is sufficient to tighten
the connection with your fingers. (Do not use
a monkey wrench because otherwise the
thread might break.)
This SMA connector with gold-plated con-
tacts is the highest quality commercial RF
connector in that size.
Carefully check the tight fit of the connection
at the antenna tip. This connection at the tip
of the antenna should best not be opened.
Slide the antenna into the vertical slot at the
rounded top end of the RF analyzer. The an-
tenna can be used either attached to the
tope end of the RF analyzer or held in your
hand. When holding the antenna in your
hand, however, please ensure that the fin-
gers do not touch the first resonator or an-
tenna conductors. Therefore it is recom-
mended to hold it at the opposite end. A
simple handle is in preparation. For a preci-
sion measurement, the antenna should not
be held with your fingers, but be attached to
the designated slot at the top end of the RF
analyzer.
Depending on the antenna type, smaller
pieces of copper foil may be attached to the
actual antenna. Do not remove or damage
these pieces because they serve the purpose
of fine-tuning.
Checking Battery Status
When the „Low Batt.“ indicator appears in
the center of the display, measurement val-
ues are not reliable anymore. In this case the
battery needs to be changed.
Taking Actual Measurements
When testing for RF exposure levels at an
apartment, a home or property, it is always
recommended to record individual measu-
rements on a data sheet. Later this will allow
you to get a better idea of the whole situati-
on.
It is just as important that measurements
are repeated several times: First, choose
different daytimes and weekdays to not miss
any of the fluctuations, which sometimes can
be quite substantial. Second, once in a while
measurements should also be repeated over
longer periods of time because a situation
can literally change „overnight.“ A trans-
ponder only needs incidentally – e.g. during
installation or repair of cellular phone trans-
mitters - to be tilted down by a few degrees
in order to cause major changes in exposure
levels. But most of all it is the enormous
speed with which the cellular phone network
expands every day. In the future we will also
have to deal with third generation networks
(e.g. UMTS/3G), which are expected to in-
crease exposure levels considerably since
their system design requires much more
tightly woven „cells“ of base stations com-
pared to current GSM networks.
Even if you only intend to test indoors, it is
recommended to first take measurements in
each direction outside of the building. This
will give you first insights into the „RF tight-
ness“ of the building and also potential RF
sources inside the building (e.g. 2.4 GHz
telephones, also from neighbors).
Furthermore you should be aware that taking
measurements indoors adds another dimen-
sion of testing uncertainties to the specified
accuracy of the used RF analyzer due to the
tightness of indoor spaces. According to the
„pure teachings,“ quantitatively accurate RF
measurements are basically only reproduci-
ble under so-called „free field conditions.“ In
spite of that, RF is of course also measured
inside of buildings because this is the place
where we wish to know exposure levels. In
order to keep those system-immanent meas-
urement uncertainties as low as possible, it is
imperative to carefully follow the measure-
ment instructions.
As mentioned earlier in the introduction, only
slight changes in the positioning of the RF
analyzer can already lead to rather substan-
tial fluctuations in measurement values. (This
effect is even more prevalent in the ELF
range.) It is suggested that exposure as-
sessments are based on the maximum
value within a locally defined area even
though this particular value might not exactly
coincide with a particular point of interest in,
for example, the head area of the bed.
The above suggestion is based on the fact
that slightest changes within the environment
can already cause rather major changes in
the power density of a locally defined area.
The person who performs the RF testing, for
example, affects the exact point of the maxi-