Page 431 - PPL BEG-engelsk

Communication

4.13.1 Frequency and wavelength

Frequency refers to the frequency of something that occurs regularly.

In connection with radio engineering and electronics, the frequency is:

the number of oscillations per second.

So, what is oscillation?

Here you can see an oscillation. It has a positive
and a negative half-period.

If you have 1 oscillation per second, you say that

the frequency is 1 Hz.

Such oscillations propagate as waves in water at a speed of 300,000 km per

second.

The wavelength is referred to as the distance from wave crest to wave crest.

However, it could just as well be the distance from the beginning of a positive

half-wave to the beginning of the next positive half-wave.

If you look at the figure above, the wavelength is 300,000 km.

Now we will try a new frequency.

If you count, you will find that we have

8 oscillations here.

Below these you can read that the 8 oscillations take 1 second. This means that
the frequency is 8 Hz.

The wavelength is therefore 300,000 km / 8 = 37,500 km

Now we can start looking at something more advanced. Let's calculate the

wavelength of Herning Radio's frequency.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© marts 2026 431