One of the key areas of any radio system is that part where the signal is transfered from the transmitter to the receiver.
This involves the use of antennas or aerials to radiate the signal as an electromagnetic wave, and then there is the way that the electromagntic wave travels or propagates between the transmitting antenna and the receiving one. Thus antennas and propagation are key areas for any radio system
All transmitted signals propagate away from the point where they are being radiated and by the time they reach a receiver, they have been transmitted over a signal path.
The path can affect the signal in a variety of ways, reflecting, refracting, diffracting, attenuating and so forth. These changes can enable signals to travel over great distances, and understanding them is key to understanding the strengths, the likelihood of hearing signals and the like.
The study of radio propagation is particularly interesting and involves many facets.
Check out these tutorials on the radio spectrum and radio propagation.
In order to transfer radio signals along a particular route a transmission line is needed. These transmission lines can take many forms including coaxial cable, open wire feeder, waveguide and even PCB printed tracks.
Key tutorials about transmission lines - what they are and key aspects about the performance and operation of transmission lines.
Radio antennas are needed to radiate and pick up radio signals. They are specially designed to optimise the radiation and reception of signals, often providing gain, directivity, bandwidth, frequency response and the like that is appropriate for the signals being transmitted and received.
Learn about antennas and how they work in these tutorials and descriptions for building and installing them.
Other antenna technologies