What is RF
Radiation? - ELF
EMF's
[EMF
Spectrum] [Ionizing]
[Non-ionizing]
[Near Field & Far Field] [RF
Hazards]
[Reflection]
[Interference]
[Faraday
Effect]
[Health
Effects] [RF
Protection] [The
SCP System]
[About
SAR] [Exposure
Models] [Glossary]
Extremely Low
Frequency (ELF) and Electromagnetic Fields (EMF's)
All life on Earth has adapted to
survive in an environment of weak, natural low-frequency electromagnetic
fields often called Schumann
Resonance
(in addition to the Earth's static geomagnetic field). Natural
low-frequency EM fields come from sources like: the sun, earth, and
thunderstorm activity. But in the last 100 years, man-made fields at
much higher intensities and with a very different spectral distribution
have altered this natural EM background, in ways that are far
from being fully understood. Much more research is needed to assess the
biological effects of EMR.
Although Amateur Radio is basically a
safe activity, in recent years there has been considerable discussion
and concern about the possible hazards of electromagnetic radiation (EMR),
including both RF energy and power frequency (50-60 Hz) electromagnetic
fields (ELF). Extensive research on this topic is underway in many
countries. More
on Amateur Radio safety and EMR Click Here
Another area or intensive research on
health effects from ELF surround power lines and broadcast stations in connection
with leukemia in humans
What are ELF electric and
magnetic fields?
The concept of an electric and a magnetic field is mathematical. It is an
indication of electric or magnetic force. The measurement of the strength of
an electric field is in units of volts per meter (V/m). Magnetic field or
magnetic field strength has three units; amps per meter (A/m), tesla (T) and
gauss (G). A common magnetic force that everyone is exposed to is the earth's
magnetic field which causes compass needles to point north.
However the most commonly known electric and magnetic fields are those
produced by electrical appliances, electrical wiring, and powerlines. These
fields change in size with time in a cyclic way and are referred to as alternating
electric and magnetic fields. When both fields are found together, it is
common to refer to them as electromagnetic fields.
What does the term Hertz (Hz) mean?
This term is used to describe how often an electromagnetic field alternates.
The word "frequency" is used to describe the number of alternating
cycles that occur in a given time. A frequency of one cycle per second for
example is called one Hertz or 1Hz. Power frequency electromagnetic fields in
North America are 60 Hz (alternating through 60 cycles per second). Extremely
low frequency (ELF) is the name given to the low frequencies. Although
there is some variation in the definitions of ELF most organizations consider
frequencies from 30 to 300 Hz or frequencies from 0 Hz to 3000 Hz to be ELF.
