Audio Analysis Of Modulation - Gigahertz Solutions HF59B Bedienungsanleitung

M a d e in G e r m a n y
wave, MW, LW, analogue radio, etc.) can be considered less im-
portant, especially when less frequently measured.
The "Bund fuer Umwelt und Naturschutz Deutschland e. V." (BUND)
proposes a limit value of 100 µW/m² for the outside of buildings. In view
of the shielding properties of normal building materials, the values in-
side buildings should be far lower. In February of 2002, the Medical
Authority of the Federal State of Salzburg, Austria, recommended to
reduce its "Salzburger Precautionary Recommendation" from 1,000
µW/m² to 1 µW/m² inside buildings and max. 10 µW/m² outside. These
limits are based on empirical evidence over the past few years.
In summary it confirms the justification of precautionary limits
well below the present legal limits.
Note for users of cellular phones or Wifi:
Unimpaired reception of calls or Wifi is possible with power densities
far below even the very strict precautionary recommendation of 0.01
µW/m² for pulsed HF frequencies by the SBM.

Audio Analysis of Modulation

The audio analysis of the modulated portion of the HF signal helps to
identify the source of a given HF radiation signal. There is a selection
of audio samples on our homepage ("Sound Samples" under RF and
EMF Meters / High Frequency).
Important: For the audio analysis please set the switch on the right of
the display to "Pulse" in order to eliminate acoustical markings ("rat-
tling" with 16 Hz) of unpulsed signals (please see next chapter for de-
tails).
How to proceed:
For audio analysis, simply turn the volume knob of the speaker at the
top of the case all the way to the left ("-"). If you are switching to audio
analysis while high field strength levels prevail, high volumes can be
generated quite suddenly. This is especially true for measurements
which are to be taken without audio analysis. The knob is not fastened
with glue to prevent over winding. However, if by accident you should
turn the knob too far, simply turn it back again. No damage will be
caused.
Sounds and signals are very difficult to describe in writing. The best
way to learn the signals is to approach known HF sources very closely
and listen to their specific signal patterns. Without detailed knowledge,
the characteristic signal patterns of the following HF sources can be
easily identified: 2.4-GHz telephones as well as cellular phones, the
signal patterns of which can be divided into "a live connected phone
call", "stand-by mode" and of special interest the "establishing of a con-
nection". The typical signal patterns of a cellular phone base station
can also be identified this way. For comparison reasons you are well
advised to take measurements during high-traffic times, as well as
some times during the night, in order to get familiarized with the differ-
ent noises.
© Gigahertz Solutions GmbH Seite 33