Understanding an RF Signal

What is RF Signal ?
A Radio Frequency signal is an electromagnetic wave that carries information over the air from one point to another.
RF signals starts as an electrical Alternating Current (AC), generated by a transmitter. This AC signal travels through the copper conductor and radiates out of an antenna in the form of electromagnetic wave.

What we see in the below diagram, is how a room would look if we were to have lot of devices emitting RF signals. These are waveforms commonly known as Sine Wave.

Just take a small portion of these RF signals and bifurcate it into 4 major variables,

a) Frequency
b) Wavelength
c) Amplitude
d) Phase

RF Spectrum ranges from 3 KHz to 300 GHz.

1VLF – Very Low Frequency 3 KHz – 30 KHz100 km – 10 km
2LF – Low Frequency30 KHz – 300 KHz10 km – 1 km
3MF – Medium Frequency300 KHz – 3 MHz1 km – 100 m
4HF – High Frequency3 MHz – 30 MHz100 m – 10 m
5VHF – Very High Frequency30 MHz – 300 MHz10 m – 1 m
6UHF – Ultra High Frequency300 MHz – 3 GHz1 m – 100 mm
7SHF – Super High Frequency 3 GHz – 30 GHz100 mm – 10 mm
8EHF – Extremely High Frequency30 GHz – 300 GHz10 mm – 1 mm

Below diagram would clearly show us how the wave pattern looks with respect to the distance it travels over the air.

CWNA Official Study Guide

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