HW V4 / © 2005 – 2013 Aaronia AG, DE-54597 Strickscheid
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Manual Spectran V4
Tables and exposure limits
12.3. Exposure limits
For radio transmitters (including mobile phones/cell towers) internationally approved
exposure limits, but also various precautionary limits and recommendations exist.
Depending on the context and country, however, exposure limits and recommendations
differ vastly.
The German limits are defined by the “Regulierungsbehörde für Telekommunikation und
Post (Reg TP)”, a subsidiary of the “Bundesministerium für Wirtschaft und Arbeit
(BMWA)”. They are mainly based on the heat generation caused by high-frequency fields.
It is assumed that effects harmful to health only occur when tissue warms by more than
1°C. These exposure limits are mostly accepted by all national and international
committees. For Germany, these limits are recorded in the “Verordnung über
elektromagnetische Felder (26. BlmSchV)” and are mostly derived from the international
recommendations. As an approval for the compliance with these exposure limits, radio
installations acquire the “reg TP Standortbescheinigung” (“installation certificate”).
The German exposure limits are designed for squared averages recorded over intervals
of 6 minutes, and are categorized by frequency ranges. Depending on the affected target
group, different limits apply. As an example, we will use the limit defined for the general
population:
Frequency [MHz]
E-field strength [V/m]
M-field strength [A/m]
1 - 10
87 /
√
f
0,73 /
√
f
10 - 400
27,5
0,073
400 - 2.000
1,375 *
√
f
0,0037 *
√
f
2.000 - 300.000
61
0,16
The adjacent diagram shows a visual representation of aforementioned formulas over a
frequency range from 1Hz to 100GHz. The graph clearly shows that the formerly
widespread broadband RF measurement instruments cannot measure and evaluate
these exposure limits correctly as they are not frequency-dependent.
