The environmental compatibility (EC) forms the generalization that includes both the
electromagnetic compatibility (EMC) and the biological compatibility (BC). Besides the
technical and functional goals of an undisturbed functional course it also pursues ethical
and moral goals.
Technology should benefit to humanity and at the same time be in accord with nature.
This goal will not be reached when this technology directly or indirectly is endangering
humanity.
A direct attack on the health of people poses for instance the military usage of technical
apparatus or the negligent usage, by pretended ignorance and unsuspicion.
Is a technology posing a danger to the environment so humanity endangers itself indirectly
with this technology. After all are human beings a product of their environment. We
always should reckon on the environmental sins taking revenge on us sooner or later.
In fig. 2.1 a formal definition is given that in particular concerns the claims for an
undisturbed functional course: it concerns the compatibility aspects of unallowed emitted
and irradiated interference radiations, the reliability and quality safety with which a
function and task is fulfilled and finally the questions of the protection of health and the
safety at work.
Moreover fig. 2.1 provides an overview and the structure of the 2nd chapter. First we'll
treat the electromagnetic compatibility (EMC) that first of all deals with the influence of
artificial but also natural interference sources on technical apparatus.
After that we'll throw a glance at the appearing fields in nature. The biological
compatibility (BC) deals with the influence on biological systems.
An especially sensitive area of the environmental compatibility (EC) than describes the
with a cross-link hinted influence of artificial interference sources on biological systems
that is popularly described as ,,electro smog".
The numerous aspects of the environmental compatibility for instance in the areas of
chemistry and biology that certainly are important, but do not fall in the area of
electromagnetism, can't be treated in the here marked framework.
2.2 Tasks of the electromagnetic compatibility (EMC)
First of all the EMC (electromagnetic compatibility) is concerned with the function of
technical apparatus. Correspondingly rational and dry sounds the official definition:
"electromagnetic compatibility (EMC) describes the ability of an electrical setting-up (i.e.
of a construction element, of a construction group, of an apparatus or of an installation) to
function in an electromagnetic environment without stressing this environment by
electromagnetic effects in an unallowed fashion ".
Actually it concerns an old need for protection that should be as old as the usage of electro
technical apparatus. But in the beginning no one cared about it. The spark gaps with which
Heinrich Hertz 1888 in Karlsruhe has carried out the first radio technical experiments
were genuine ,,polluters", that would have been detectible at several hundreds of
kilometres distance with modern receivers. For these installations that he had assembled in
the lecture room with his students, today he would hardly get a permission of operation
and the since 1996 required declaration of conformity he would get not at all.
1925, as in Germany the number of radio listeners had exceeded the limit of one million,
for the first time a need for protection appears in the certificate of approval for radio
receivers: "The public telegraphs and telephone installations must not be disturbed by the
radio receiver".
Later on every backside of the good old steam radios there was found the following hint
(translated): "This apparatus meets the interference radiation regulations of the German
Post Office". So the manufacturers were urged to measure the emission of their apparatus
and in particular to screen the HF-oscillators in the superhet-receivers.
Since the fifties, in the VDE-institute EMC-examinations in the present day sense are
taken. The main point of the measurements and the by the VDE recommended limits,
however is about interferences bound to a circuit. On the supply lines of the network the
prevailing conditions are reproducible so that standards can be put through (Fig. 2.2).
For measurements of interference radiation maybe the time was not ripe enough or the
necessity was not big enough. The usual argumentation was: what we can't measure
reproducibly, can not be forbidden and certainly not be put under punishment. Therefore
merely recommendations were issued or impositions weak as wax were made like: "the
interference field strength ... must be so small that an undisturbed reception is guaranteed
as soon as the minimum field strength for utilization exists at the place where the antenna
is mounted".
In common parlance that means something like: "as long as no one bleats, everything is
allowed". Within a connected industrial area there even existed an officially legitimized
fools freedom. Merely at the fence of the industrial area limits had to be fulfilled.
Specially for the line-frequency of the screen one has decided to build a loophole in the
law so that one didn't have to throw the TV sets, that so successfully had conquered the
living rooms, out of the window. Of course the flickering screens did interfere exactly as
before but this EMC-interference now was officially approved.
2.3 Declaration of conformity
In the EMC times seem to have gone as the standardizers had to fit in with the insufficiencies
of technology. Meanwhile the conditions have turned up. We owe this circumstance
first of all the EMC-law of 1992 that doesn't name any limits but it states the
political intention to demand from technical apparatus and installations an appropriate
stability against interference and at the same time limit the sent out interference.
As a consequence of this law the measurement facilities and measurement processes had
to be standardized to get reproducible measurement results that are not influenced by the
electromagnetic environment. That goes so far that even the floor covering of a
measurement hall is dictated because the conductivity of the floor influences the degree of
reflexion. Normally the examinee is situated on a revolving plate that is turned around for
360° during the measurement of the radio interference field strength. Is it however not
possible to turn the examinee than the antenna has to be led around it, thereby again
increasing the dimensions of the measurement hall. The distance to the antenna should be
up to 10 meters. Moreover it must be possible to move the antenna, up till a height of 4
meters to register the influence of the reflexions on the floor.
Moreover there is to plan a reflexion free zone around the measurement track (in elliptical
form) that depends on the reachable damping of reflexions of the used absorber. Used are
pyramids of foam material soaked with carbon and increasingly tiles of ferrite or
shieldings of wallpaper.
Taken all together for a measurement hall doing justice to standards there result
considerable measurements of for instance 18 m length x 10 m width x 7 m height.
Let's again come to talk about the EMC-law with which only the intention but not the way
is fixed. To form the claims catalogue in a way that is fulfillable in general, some concrete
prescriptions, the so called standards, have to be worked out. This task was transferred to
the European committee for electro technical standardization CENELEC, which has
established the workgroup TC 110 to at first work out some standards:
The basic standards deal independent of product with general questions of the EMC, of
the testing process and of the measurement environment.
The generic standards likewise deal independent of product with the so called
fundamental technical standards for apparatus in their dependence of the respective
electromagnetic environment (protected computer room or medical room, environment of
the house, office or industry).
The product standards concern the EMC-standards referring to products (7 product
families / approx. 50 products).
In Fig. 2.3 the arduous way through the jungle of paragraphs for a technical apparatus is
outlined. Corresponding to the requirements of use, first the relating ES-standards for the
apparatus have to be determined and than have to be measured according to own test
standards based on the fundamental technical standards. When the allowed limits for
stability against interference and for sending out interferences are not exceeded, the ECdeclaration
of conformity is handed out. Since 1.1.96 that declaration is needed when
apparatus are commercialized or - stated more exactly - "put in circulation" and operated.
When still further EC-guidelines are met in the end the CE-hallmark is awarded. Since
1.1.96 only with this hallmark the access to the common market of the EC is possible.
Violations can be punished with fines and if need be with imprisonment. But there are
great national differences in the EC. The Federal Republic of Germany with fines of up to
50.000 Euro counts as expensive for criminals.
2.4 EMC-techniques to measure the emission of interference
Actually we already can be glad that it came to an europe-wide agreement for the
regulation of the EMC-set of problems. But the question if we can be satisfied with what
we have reached is still outstanding. All too often the lowest common denominator of the
measurable and checkable was sought and not so much the technical possible was taken
into consideration.
The main emphasis is put on the measurement of the emission of interferences.
Traditionally the interferences bound to a circuit are registered in a frequency range up
to 30 MHz. The corresponding wavelengths thereby can correspond with the length of the
supply lines and form standing interference waves. Primarily the spectrum of the
interference currents is measured e.g. over a HF-current converter. These currents
produce a voltage drop over the internal resistance of the feeding network. Because the
properties of the networks can vary very strong, a standardized end-resistor is required for
the measurement of the interference voltage. For this purpose an imitation of the network
is switched between the network and the examinee. This imitation in addition has the task
to keep away the interference signals that come from the supplying network with the help
of filter-elements (Fig. 2.4).
The measurement of the interference radiation, the field-bound interference emission,
lakes place between 30 MHz and 1 GHz. For that a free field or an absorber-hall with
little or no reflexions is required. The standardized distances of measurement are 3, 10 and
30 meters. The electric field strength is determined with dipole broadband antennas, the
magnetic field strength with frame antennas. It must be possible to both vary the receiving
antenna between horizontal and vertical polarization and to adjust the receiving antenna in
the height and the position to the test object.
2.5 Electro-Smog
There is almost no end to the possibilities of variation and one needs already a lot of
overview and experience to determine the field strength maximum. Nevertheless we have
to ask ourselves if in this way really all emissions of interference are understandable, that
popularly are described as ,,electro smog".
Smog is the combination of the terms Smoke and Fog. It therefore describes a pressure on
the environment with fog like smoke. When for instance in the case of smog alarm all
interference sources are switched off, which means all kilns are brought to a stop and all
automobiles are stopped, than the fog like smoke therefore still is not vanished from the
air. It just distributes itself and dissolves only very slowly.
The transfer of the smog idea on the electromagnetic interference radiation is bound to fail
because, when the test object is switched off no emission of interference at all is detectable
with the usual measurement means. Nevertheless the rainbow-press is trying to enumerate
almost all electromagnetic field phenomena under the term ,,electro smog" without
consideration of the fact that this term is not at all a collection term.
From the sight of an expert one can only speak of smog when something like smog
remains and stays active further after the switching off of an electro technical apparatus. It
should be a phenomenon that is not understandable by the standardized measurements of
interference radiation. Such a phenomenon would be e.g. the vortex of the electric field.
However vortices are virtually not measurable in a direct way because they have the
unpleasant property to whirl about around the measurement probe. But they will be
detectable by their eddy losses and in the case of the electric field vortex appear as noise.
Until now the standardizer however haven't planned to investigate the influence of an
apparatus on the noise in the environment. Here we still grope in the dark.
At least the vortex shows a storing property that would justify the use of the idea "smog".
We'll have to investigate the phenomenon.
2.6 EMC-techniques to measure the stability against interference
The question is: what kind and what intensity of an electromagnetic interference can an
apparatus cope with without limiting it regarding its technical function.
For that test generators are used and with their help interference signals are produced in
the test object. Fig. 2.6 shows the possibilities of a symmetrical, of an unsymmetrical and
of an asymmetrical production of interference voltage signals in the power supply lines of
an examinee. Over and above that the testing possibilities and testing methods are
numerous. In principle the following processes are used:
1. The simulation and production of interference factors typical for the network like
harmonic waves on network voltages, overlapping signal voltages, changes of network
voltage, decrease of network voltage, network interruptions, network unsymmetries and
network frequency changes.
2. The production of both energy-poorer and energy-richer interference impulses like they
can form in energy-networks by switching acts or by the effect of lightning (burst).
3. The simulation of the course of events when static electricity discharges.
4. Low-frequency magnetic fields like those that can form by network frequency operating
and loading currents or by short-circuit and lightning currents in the form of a pulse.
5. The stability against interference against the influence of an electromagnetic field also
called radio interference firmness. For this purpose high-frequency generators and
broadband antennas are used to expose the examinee to electromagnetic fields in a
frequency range between 10 kHz and 18 GHz. At the moment tests are only performed
between 27 and 500 MHz. The modulation of the carrier wave should be possible to be
able to imitate the interferences by radio technology as realistic as possible. Thereby
the field strength values can by all means reach up to several 100 V/m.
In accordance with expectation the result of this irradiation with an outside field is that
every conduction path and every wire can act as an antenna and therefore can produce
high-frequency currents and measurable potentials. Building parts of the analog technology
as a consequence battle with problems of drift whereas with digital logic parts and
computer parts the danger exists that switching states change unintentionally. Let us
remember again the overlap effect of fig. 1.4. The electromagnetic wave itself marches
wi t h the speed of light through the examinee. When a small part of the wave finds an
object that it can use as an antenna than the localized overlap comes into play. This than as
a cause is responsible for the effective and measurable antenna currents. Until here the text
books help us to explain the problems that happen and to remove them logically.
However time and again cases are reported where textbook physics can't help us any
further. Spectacular cases even came to court like e.g. the ABS (Antilock Braking System)
of a truck that had failed due to EMC-interference radiation. As a consequence the brakes
had failed. When after that the local radiation pollution is measured no anomaly at all can
be discovered. The measurable field strength is not higher as is usual in the whole area.
Maybe you also have made the experience that often the causes can't be found when your
computer suddenly "crashes" out of the blue.
Here the mentioned vortex of the electric field is capable to deliver plausible explanations
because it is not bound to the geometry of an antenna and in addition is highly active
without being detectable with the usual EMC measurement methods of the interference
radiation measurement!
2.7 Tasks of the biological compatibility
The second leg of the environmental compatibility (EC) forms the biological compatibility
(BC) besides the electromagnetic environmental compatibility. Whereas the interests of
the EMC are looked after by electrotechnical engineers and electrophysicists, with the BC
also doctors, biologists and architects are addressed.
Moreover this leg is already very old and already existed long before artificial interference
sources could be created by mankind. The interaction between the arising interference
sources in nature and the biological systems in general and specially men always
interested the doctors, the priests, the druids and geomants, that not seldom looked after
several functions in personal union equally. Unfortunately they as a rule have kept their
knowledge and capabilities as secret knowledge, didn't make any recordings and merely
initiated and trained their respective successors. Through that a great deal got lost and
today non-medical practitioners, homeopaths and esoterics trouble themselves to take up
to the far-reaching buried knowledge.
Because this concerns pure knowledge by experience, often the with the topic occupied
persons themselves are not capable to say anything about the physical backgrounds and
causes. One concentrates entirely on the under certain circumstances reachable results and
only in rare cases on reproducable effects. In some areas the scientific assignment already
has succeeded, have parascientific phenomena managed their admission in the so called
"exact sciences", but in most experience disciplines the assignment is still due. There still
is a lot to do here.
In the time as there not yet were operated any artificial interference sources on our planet,
the senses of man naturally were a whole lot sharper for his electromagnetic environment
as today. Today, where there scarcely is a place on earth where we are not irradiated by
terrestrial transmitters, by satellites or by the netfrequency that is measurable everywhere.
In the bluntness of our senses perhaps the hybris of modern man is founded, with which he
wants to rise himself above esotericism, geomancy and other sciences of experience and
thereby dispute the electric and magnetic fields their biological effectiveness.
The fields of natural origin form an electromagnetic environment for men, that they have
adapted to and that they probably need for a life in accord with nature. The evolution has
taken care for a corresponding adaptation.
In fig. 2.7 in addition to the limits from fig. 1.1 the intensities of natural electromagnetic
fields are registered. They lie clearly lower as the recommended limits but exactly in the
area wherein the first reactions of living beings are observable.
When we ask us how much electromagnetism is good for us and how much harms us so
the obvious answer is: exactly as much radiation as nature dictates in the fluctuations
between day and night, between the months, years and in the end between the cycles of
sunspots of 11 years. Here the guide value is found that man and nature have adapted
themselves to. In fig. 2.7 the corresponding area between the natural minimum and
maximum values is given.
2.8 Natural fields
Our electromagnetic environment has something to offer:
From the magnetic north pole to the magnetic south pole of the earth run the field lines of
the earth's magnetic field that we are exposed to. With a compass we use the vector
character of the magnetic field to fix our position. The induction averaged over time is
approx. 50 uT. But it is overlapped by short-time fluctuations caused by geomagnetic
storms in the ionosphere.
These storms again are caused by the eddy currents and the currents of charged particles
that come from the sun. At the same time these eddy currents in the ionosphere together
with the earth's magnetic field form a protective shield with a excellent screening effect
for us inhabitants of earth.
In several layers like for instance the ozone and Heaviside layers a filtering and damping
until the complete suppression of the very broad cosmic spectrum is caused. This
extraterrestrial spectrum of radiation doesn't leave a single frequency out and has a lethal
intensity for us.
Only for a little window in the frequency spectrum, radiation can pass almost undamped,
as can be seen in fig. 2.8: the light with the spectrum of the colors. For this nature has
donated man a sense organ so that man can protect himself against too high dose values.
After all, who will look voluntarily into the sun? We only get into trouble when our sense
organ doesn't function any more (for instance in the fringe range of the visible spectrum,
the UV-range).
For other frequencies of electromagnetic radiation man neither has a sense organ but that
doesn't mean that he is not influenced by these. Here, as in the UV-range he only
indirectly notices that he has got too high a dose when he has to discover some influences
on his well-being and his health. Without the help of neutral measurement apparatus he
himself by no means is in a position to make a connection between an excessive
exposition to radiation and his health problems.
When natural field strengths should be used as a measure for technical limits, so there
should be paid attention to the fact that nature doesn't know intense continuous
irradiation. The values are subject to powerful fluctuations that leave men and nature the
chance to regenerate.
The television stations not even think it is necessary to reduce their broadcasting power
after the end of broadcasts and further sprinkle the sleeping population with test signals,
with senseless pictures of going by underground or nonstop program advertisements.
People need the intermissions. That again shows how good nature means it with us.
2.9 Electricity of the air
The electrostatic field strength of the earth lies between 50 and 500 V/m. That is a whole
lot considering that voltages off 60 Volts can be lethal for man. But a living person
distorts the terrestrial E-field for reason of his own field and his electric conductivity, so
that there exists no danger for him as long as he doesn't grow into the sky.
Maybe the dinosaurs had to become extinct because they were to big and for instance the
E-field near the ground had risen with a jump by a meteorite that brought a high charge
from the cosmos. That would explain why the smaller living beings could survive the
natural disaster.
Also the thunderstorm electricity can become life-threatening. Burns, heart and brain
failures are the most common consequences. After all the probability to be struck by
lightning is four times higher as to have six right ones in the lottery.
Over the lightning channel of approx. 1 meter in diameter charges between 10 and 200 C
are transported what results in current strengths of 2000 up to 200,000 A. The main
discharge lasts between 10 and 50 usec. With the preceding and all the following
discharges it lasts over a second.
Field strengths on the scale of 4,000 V/m are typical but in a distance of 5 km these wear
off to 8 V/m. The frequency spectrum of a lightning reaches 4 powers of ten into the range
of the radio waves. In fig. 2.9 is shown the field strength measured in a distance of 1.6 km
from the place of origin
The origin of lightnings is still an unsolved problem after the well-known models (Wilson)
arc not in a position to explain the reason for the origin of the potential difference of more
than 100 million Volts required for the ionization of the air. Also the lightnings that struck
in the direction of the ionosphere still are mysterious.
We'll have to come back to this
2.10 Biological effects
The in fig. 2.1 indicated connection between the EMC and the BC, by some authors
inofficially described as EMC-environment (EMCE), describes the effect of artificial
fields on biological systems. This concerns the sensitive range of tasks that is discussed
extremely controversially in the public. The problem thereby is that the artificially
produced field strengths lie above the natural field strengths for several scales.
In the thirties first reports about troubles were provided by navy radio operators that
complained about headache, dizzyness, concentration failure and indisposition. Besides
these negative reports concerning the so called "radio operator disease" at the same time
medical usages concerning high-frequency therapy were tested. In the beginning this
diathermy called healing method still was a short wave irradiation. Today it is extended
into the microwave range and uses the thermal effect of electromagnetic rays. The
increased temperature of the tissue causes an increased local blood flow. This supports
healing processes, loosens cramped muscles and can help in case of rheumatic fever.
The advantage of the HF-irradiation compared to contact heat by a hot-water bottle or by
infrared rays is the higher penetration depth. Herein short waves are superior to
microwaves. But microwaves can be better focussed on a certain part of the body.
Is the temperature further increased, so the tissue is damaged. This is used for the
treatment of cancer and is called hyperthermy. Because cancer cells as a rule are flowed
wi t h blood worse than healthy cells, they are more sensitive to heat and therefore are faster
destroyed than healthy cells at a correspondingly increased temperature. In this way for
Instance in the USA cattle with a so called cancer eye are treated. For that the spot
suffering from cancer is irradiated with 2MHz-waves for 30 seconds with a handheld
apparatus of 10 Watts broadcasting power. The rate of succes is given to be 90%!
The method of hyperthermy has not yet been able to establish in the area of the medicine
for humans. Also at our college corresponding research work is carried out in co-operation
with the radiological clinic of the university of Freiburg (Germany ).
T he thermal effects of high-frequency fields are therefore well-known and subject of
scientific research. On the other hand and in spite of numerous publications, non-thermal
effects even today are denied by some scientists as non-existent
counter-examples will be listed.
Fig. 2.10 A shows the effect of a static magnetic field of 0.12 Tesla on the root (1) and on
thc plant (II) of barley seeds. The readable effect is an acceleration of the growth of the
treated seeds (dotted line) compared to the plants for checking (drawn line)
A static field naturally produces no induction and hence no heating will arise. In the case
of alternating fields the thermal effect in experiments is excluded by working with
cxtremly low stimulations. The example after fig. 2.10 B shows the measured increase in
the production (K) of colicin by colibacteria at only 0.01 mW/cm2 microwave power.
In addition the example provides the interesting information that obviously only a certain
frequency and it's harmonic waves increase the production, other frequencies on the other
hand remain inactive. Because only minimal field strengths are used it more likely
concerns an information-technical as an energetic effect (curve a). This statement is
supported by the observation that an increase of the intensity not at all necessarily as a
consequence also increases the production (curve b). What the colibakteria need is
obviously neither energy nor heat but only a certain frequency that stimulates the colicin
production or the growth.
Should it really be confirmed that biological effects of electric and magnetic fields can be
produced by certain frequencies and can't happen by an energy transition so the
discussions about limits must seem ample meaningless.
Maybe the one or the other in thought already draws a connection to the acceleration, the
acclerated growth of kids, which is observed world-wide and stronger in cities than in the
country. It started for approx. 100 years simultaneous with the electrification of the homes
in the towns. In Asia the acceleration and also the electrification have started later.
Other growth stimulating effects like radio waves, X-ray examinations, atomic tests and
provable also the nourishment with vitamin B6 happened only until much later and at the
most could support the actual effect.
But how should a proof be offered when anyway the field strength not at all can have a
decisive influence on the growth of man after the statement of fig. 2.10 B? Which
information is authorative? Where lies the responsible frequency window? Does the
information actually manifest as frequency? Is the authorative influential factor also in this
case not at all noticed and measured?
A lot of pressing questions are still outstanding. But in any case the numerous influential
factors detected in experiments do not at all let themselves reduce to a sole factor, for
instance the nourishment. For a family doctor it may be comfortable to be able to give an
easy explanation: ,,Cause is the nourishment!" With such a reductionism on the other hand
the actual cause stays in the dark and the asked questions in this way won't let themselves
be answered.
2.11 Artificial fields
The scepticism of people feeling close to nature is especially directed against artificial
fields that man can't see nor hear nor smell. Objects of doubt are first of all the
installations for the creation, distribution and conversion of electric energy.
An essential role plays the fact how close the supplying and the draining conductors are to
each other, so that the respective fields can compensate each other. The worst solution one
can think of is realized at the electrified railway. Here the rails and the earth are used as
the draining conductor for the current while there exists an ample large distance to the
supplying conductor. A compensation is almost impossible thus causing gigantic
interference fields that are detectable even at a distance of 10 kilometers. The increased
putting on of railway engines feeded by rectified current is likely to aggravate the set of
problems because the non-sinusoidal absorption of current is strongly afflicted with
harmonic waves.
With high tension transmission lines (fig. 2.11) the interference field strength is reduced
when the three cables are suspended with only little distance between them. But even the
selected phase order can play a role. Of course the optimal compensation effect is
guaranteed with cables in the earth. But these are expensive and technically not realizable
for such high voltage levels.
In the eighties also the computer screens got in the headlines. The terminals are furnished
with a cathode ray tube and have a very broad radiation spectrum that already starts at 0
Hz. Here already static maximum values of 64 kV/m are measured!
I'requency range Measured maximum 30 cm in front of
values Emax resp. Hmax the screen
static field (0 Hz) 64 kV/m
30 Hz. 60 Hz 10 V/m and
0.2 - 1 A/m
5 Hz - 1 kHz 1800 V/m and 10 V/m and
4 A/m 0,6 A/m
50 Hz - 0,5 MHz 1 A/m
15 kHz-220 kHz 50 V/m and 15 V/m and
1.1 A/m 0,17 A/m
3 MHz -300 MHz < 0,2 V/m
system used frequency
about
measured
value
radio broadcasting station
(MW 2O kW)
6OO kHz 2...17 V/m
radio broadcasting station
(SW 1OO kW)
15 MHz 1...25 V/m
SOS-transmitter
on a ship (1OO W)
41O kHz 1...3 V/m
Epitaxiedevice
(induction oven)
45O kHz 37...4OO V/m
HF-welting press
(welding of plastic foils)
27,12 MHz 70...85 V/m
radar on a ship
(TRN 311)
9,3 GHz 1...3O uW/cm2
radar of an airplane 9,2 GHz 45O...
28OO uW/cm2
domestic appliances measured in a distance of 3O cm:
hand mixer
refrigerator
5O Hz
5O Hz
5O V/m
6O V/m
Fig. 2.12: ____ the electric field strength resp. Power density
in our environment.
2.12 Protection against artificial fields
Artificial fields more or less always occur in the neighbourhood of electric apparatus and
installations. Especially problematic are those that work with the free radiation of
electromagnetic fields, that is all the radio broadcasting stations, handheld and radar
transmitters.
Herewith it is important that not needed parts of the antennas are shielded, that antennas
with little close by field pollution are used and that the stand should be situated at least 3
km remote from inhabited areas. For instance at radar installations damping values of 10
dB and more can be obtained only by using a corresponding tree growth.
This obviously concerns a damping of the waves in a dielectric manner. We'll have to
come back to this because textbook physics does not know a corresponding damping term
in the wave equation.
The radiation leaking out in case of the high-frequency welding of plastic foils and of the
microwave oven should be minimized.
In the case of induction ovens or of motors an active shielding often causes problems so
that for simple domestic appliances like a hand mixer and especially for the electric hairdryer
non proportionally high field strength values are measured. Fig. 2.12 informs about
it.
Protective measures for the operator are hardly possible. To protect uninvolved people not
only the apparatus but also the rooms and eventually whole parts of buildings had to be
shielded and grounded.
Sometimes also fairly simple possibilities are helpful like e.g. the usage of a remote
control. By clearing away the cable salat at the workplace and at the sleeping place
induction loops can be removed. Alarm-clocks operated by batteries should have
preference over those operated by the network. Mattresses with metal in them and springbeds
which clearly act as an antenna should be avoided. In extreme cases even so called
"current-free switches" and shielded network lines are recommended (fig. 2.13).
In the area of the network supply lines a choking coil can help decrease the spreading of
high-frequency interference radiation. It is especially important that all the conducting
metallic objects like e.g. water pipes, heatings, steel racks, machines, switching racks,
steel armaments and metallic windows should be grounded properly, because otherwise
extremly high static charges could result instead of a shielding. Construction biologists
recommend to when possible do without metals when building houses and furnishing,
what of course is only realizable with limitation.
In any case numerous measures are known that to a lesser extent find their legitimation in
classical physics, but more likely in precaution. As long as we do not know which
phenomenon causes the electrosmog and we don't have a measuring-instrument at our
disposal, precaution is really the only thing we can do irrespective of the effectiveness of
the measures and of the arising costs!
2.13 Unsolved tasks
The report concerning the actual state of research could be continued at will. But the
expositions should suffice, to understand what are the tasks of the electromagnetic
environmental compatibility (fig. 2.1) and which questions still have to be supplied with a
solution. One can get deeper into every of the addressed points and then discover that
some questions can be expressed sharper and maybe conceivable answers can be found,
but at the same time and unavoidable the number of new questions increases faster.
Let us again take up the example of the handheld wireless telephones (chapter 1.2). At
least it now is clear to us that the usage of the built-in microwave antenna of a handy is
problematic. In the interior of an automobile it never should be used. If, however, one uses
the antenna installed on the outside on the sheet metal then the damping and screening
effect of the sheet metal chassis is advantageous at least for the handy user.
With that of course the central question is not answered. The question of what the cause is
for the interfering and at worst health endangering effect of the HF-radiation. Field
freedom we can't find anywhere on this world. Possibly we even need the fields. But then
the question is how much is necessary, how much is healthy and how much makes us ill.
The gap of explanation especially gets clear in the case of the static or of the lowfrequency
magnetic field: away from technical interference sources normally fields on the
scale of 10 nT are measurable. Construction biologists say that 20 nT, so twice that value,
should not be exceeded at the sleeping place and maybe 50 nT at the desk. These values
however are determined purely empirical.
When a person is examined in a nuclear magnetic resonance tomograph that person is
exposed to a field that lies between 0.2 and 1.5 Tesla. that is a value 7 till 8 powers often
higher than before mentioned without this leading to the death of that person. Entirely on
the contrary this method is regarded as especially caring and safe compared to the X-ray
examination.
Here again the legitimation of the thesis put forward is entirely comfirmed. The thesis that
the well-known physically measurable and controllable phenomena can not be considered
as a cause and that possibly a until now undiscovered field phenomenon should be called
to account.
Should such a phenomenon exist it should be derived, calculated and proved. We must go
to endless troubles and try everything. The actual difficulties wherein the electromagnetic
environmental compatibility is stuck are a challenge.
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