FREQUENCY

RF Frequency is an electromagnetic wave using AC (Alternating Current).

Just as the name implies, “frequency”, its something that happens over and over and over again. It is very frequent, consistent, and repetitive.

There are different types of frequency; light, sound and in our case radio frequency (RF).

“*Frequency is the number of times a
specified event occurs within a specified time interval. A standard measure of
frequency is hertz (Hz)” – The CWNA definition of frequency v106 *

This specified event mentioned in the CWNA Study Guide is the cycle.

CYCLE

“*An oscillation, or cycle, of this
alternating current is defined as a single change from up to down to up, or as
a change from positive, to negative to positive.” – The CWNA definition of
cycle v106 *

Lets look at a few examples of a Cycle.

Example 1 – (1) Cycle

One cycle, specified event, is measured 1 second in time which equals 1 Hz. As the CWNA mentioned, “alternating current is defined as a single change from up to down to up, or as a change from positive, to negative to positive”

Example 2 – (5) Cycles

Five cycles, specified events, measured 1 second in time which equals 5 Hz.

We are dealing with simple math – 1 and 5 cycles per second. Imagine for a moment 2,400,000,000 / 5,000,000,000 billion cycles in 1 second. Thats a lot of cycles, eh ? That is the number of cycles 2.4 GHz and 5 GHz (WiFi) uses to transport data from one radio over the air to another radio.

High frequency simple means there are more cycles per second.

Example 3 – Low and High frequency example

So — Remember —- Frequency is simply something that repeats itself over and over again. It is measured in cycles per seconds. The more cycles per second, the more frequency or referenced as higher frequency.

WAVELENGTH

*“Wavelength is
the distance between similar points on two back-to-back waves.” – The CWNA
definition of Wavelength v106 *

RF Waves can be measured at different points. In the below example, reference #1 is the most often way wavelength is measured.

Example 4

AMPLITUDE

*“Amplitude is
the height, force or power of the wave” – The CWNA definition of Amplitude
v106*

What is important to remember — frequency, cycle and wavelength remain constant, however, the height of the wave form is dynamic based on the power of the wave. The higher power, or amplitude, the higher the wave form peeks. The lower the power, or amplitude, the lower the wave form peeks all while frequency, cycle and wavelength remain the same.

Example 5 – Amplitude shown by the height or peeks of the wave form.

PHASE

The phase is the same frequency, same cycle, the same wavelength, but are 2 or more waveforms not exactly aligned together.

*“Phase is not a property of just one RF signal but instead involves the relationship between two or more signals that share the same frequency. The phase involves the relationship between the position of the amplitude crests and the troughs of two waveforms.*

*Phase can be
measured in distance, time, or degrees. If the peaks of two signals with the
same frequency are in exact alignment at the same time, they are said to be in
phase. Conversely, if the peaks of two signals with the same frequency are not
in exact alignment at the same time, they are said to be out of phase.”
– The CWNA definition of Phase v106*

Example 6

Below is an example of 2 waveforms 90 degrees out of phase.

*“What is important to understand is the effect that the phase has on amplitude when a radio receives multiple signals. Signals that have 0 (zero) degree phase separation actually combine their amplitude, which results in a received signal of much greater signal strength, potentially as much as twice the amplitude. If two RF signals are 180 degrees out of phase (the peak of one signal is in exact alignment with the trough of the second signal), they cancel each other out and the effective received signal strength is null. Phase separation has a cumulative effect. Depending on the amount of phase separation of two signals, the received signal strength may be either increased or diminished. The phase difference between two signals is very important to understanding the effects of an RF phenomenon known as multipath, ” – The CWNA definition of Phase v106*

Example 7

Below is an example of 2 waveforms 180 degrees out of phase.

*“If two RF
signals are 180 degrees out of phase (the peak of one signal is in exact
alignment with the trough of the second signal), they cancel each other out and
the effective received signal strength is null.” The CWNA definition of
Phase v106*