文档介绍：Reading 23 Ron Bertrand VK2DQ
IC RADIATION
THE MECHANISM OF RADIATION
The purpose of this reading is to describe ic radiation and how it actually
radiates. We also cover the concept of wavelength and frequency. We look at an overview
of the ic spectrum.
Again I am faced with the dilemma of providing some information which is not examinable.
However, such information provides useful insights to the topic, which I believe makes it
more interesting.
Though radio waves can have different wave shapes, I would like you to think of them as
sine waves for this exercise. Actually many are just that, sine waves. We have already
looked at alternating current and voltage at lower frequencies, for example the mains,
which is 50 Hertz. Radio waves are produced by AC, yes the AC you have already learned
about. The difference is the frequency of oscillation is much higher than 50 Hz.
We have also learnt that current, either alternating or direct (or any other), has associated
with it electric and ic fields. It is usual to refer to bined fields as
ic fields.
It was discovered that high frequency ic currents in a wire (antenna), which
in turn result in a high frequency ic field around the antenna, will result in
ic radiation which will move away from the antenna into free space at the
velocity of light (approx. 300,000,000 metr