10.0 Exposure limits
38
Also, the difference between the exposure limits for a certain group of people
and the corresponding “maximum limits” are well visible.
Some math:
For D-Net (GSM900) cell towers, this means that the electrical field strength
needs to stay below 1,375 * 935 MHz or approx. 42 V/m.
For E-Net (GSM1800) base stations, this means that the electrical field strength
needs to stay below 1,375 * 1800 MHz or approx. 58 V/m. A huge difference!
Please note that the
allowed absolute maximums
are another
32 times hig-
her
The highest exposure to high-frequency radiation is mostly caused by the high
transmitting powers of TV and radio broadcast towers. Contrary to widespread
belief, however, often it’s not the cell towers that cause the strongest exposure
to radiation in homes - it’s often portable phones (so-called DECT phones) or
microwaves ovens.
10.2 Device exposure limits
Contrary to the personal security limits, the so-called
device
exposure limits are
often SIGNIFICANTLY more restrictive and much more frequency-dependent.
For example, a cell phone has a totally different device exposure limit than a TV
broadcast station. Here, the allowed limits can easily vary by a factor of millions!
Still, all device exposure limits also need to adhere to the personal securi-
ty limits and are thus a subset of those.
A particularly restrictive example is
the ISM868 band. It offers extreme dynamics inside a very small frequency
range:
868,0
868,6
868,7
869,2
869,3
869,4
869,65
869,7
870,0
ERP [mW]
500
25
10
5
[MHz]
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176
Summary of Contents for SPECTRAN HF-2025
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