Properties Of Hf Radiation And - Gigahertz Solutions HFW59D Manual

M a d e in G e r m a n y
Note
Each time you make a new selection (e.g. switch to another measure-
ment range), the display will systematically overreact for a moment
and show higher values which will, however, droop down within a cou-
ple of seconds.
The instrument is now ready for use.
In the next chapter you will find the basics for
true, accurate HF-measurement.
Properties of HF Radiation...
This instruction manual focuses on those properties that are particu-
larly relevant for measurements in residential settings.
Across the specified frequency range (and beyond), HF radiation
causes the following effects in materials exposed to it:
1. Partial Permeation
2. Partial Reflection
3. Partial Absorption.
The proportions of the various effects depend, in particular, on the
exposed material, its thickness and the frequency of the HF radiation.
Wood, drywall, roofs and windows, for example, are usually rather
transparent spots in a house.
Minimum Distance
In order to measure the quantity of HF radiation in the common unit
"power density" (W/m²), a certain distance has to be kept from the HF
source.
For measurements in the lower frequency limits of the HFW59D, the
minimum distance between the antenna tip and the object of meas-
urement should be half a meter.
Polarization
When HF radiation is emitted, it is sent off with a "polarization". In
short, the electromagnetic waves propagate either vertically or hori-
zontally. Therefore, both planes of polarization ought to be checked in
order to identify the one applying to the object in question. Please note
that the antenna supplied with this instrument measures the vertically
polarized plane if the upper surface of the meter is held horizontally.
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