1. Basic Radio Communications
Uncontrolled copy not subject to amendment
Basic Radio Communications
Learning Outcome 1
Understand types of radio equipment used within the Air Cadet Organisation
Version 2.10 OCT 2014

2. Introduction to radio

3. Introduction To Radio Radio has revolutionised communication
The Air Cadet Organisation has its own nation wide system of radio stations
This Network uses High Frequency (HF) for long range
Communications play an important part in every day life
Introduction to Radio
1. Communications are an important part of everyday life. We constantly need to pass on information, thoughts and ideas from one person to another. This is particularly important in a military environment, where intelligence of enemy activity can play an important role in the success or failure of a mission.
2. The invention of radio has revolutionised communication for everybody. Using radio waves, people can now communicate all over the world with relative ease. Radio is not the only means of communications in this day and age. The telephone (including the mobile phone), internet, facsimile (fax) and video all play an important part. This section introduces you to radio communications, its limitations and its benefits. Radio systems can be used to transmit various types of data as well as voice. As a Cadet you will learn how a simple radio system works and how to operate it correctly, efficiently and safely.
3. The Air Cadet Organisation is fortunate, in that it has its own nation wide system of radio stations and usually operates on most Sunday mornings. This system was originally set up just after the Second World War to train Cadets in the use of High Frequency (HF) radio equipment, and is called a "network".

4. The word network is used because ....
Networks (Nets)
The word network is used because ....
.... a number of radio stations work together, connected by the invisible strands of a single frequency –
rather like a net
Networks
The word network is used because a large number of radio stations are working together, connected by the invisible strands of a single frequency - rather like a net.

5. Networks (Nets) Directed (or Controlled) Net Free Net
Where the control station directs all communications
Free Net
Where each station is free to communicate as it needs
Networks (Nets)
There are two types of Nets:
Directed (Controlled) Net
Where the control station directs all of the communications
Free Net
Where each station is free to communicate as it needs.

6. Networks (Nets) Directed Net :
Controlled by the Network Control Station (NCS)
A group of stations using the same frequency
Always controlled
You must ask permission to join and leave the Net
NETWORKS (NETS)
4. A Directed Network (Net) is a group of radio stations each operating on the same frequency for the purpose of communicating with each other. A Directed Net is always "CONTROLLED", i.e. there will always be a "Network Control Station" (NCS) controlling the radio communications. Stations must be given or must obtain permission from the NCS before communicating with another station on the Net. It is also necessary to ask permission when joining and leaving the Net.

7. Networks (Nets) Directed Net The Network Control Station (NCS) should:
Have efficient equipment
Have experienced operators
Be able to handle the volume of radio communications to be passed
Net Control Station
Only one station on the network can act as the NCS (network control station) at any one time. A number of factors will dictate which station is chosen to undertake the NCS duties for any specific occasion. Some of these factors include:
a. Equipment efficiency.
b. Operator experience.
c. Volume of radio communication to be passed.
6. It is usual for the NCS to be a fixed base station, located in a room intended specifically for radio operations - the radio communications room.

8. Networks (Nets) Free Net No NCS (Network Control Station)
No permissions required
All stations are “Free” to contact each other
7. A network operating without a NCS is called a “Free Network” (Free Net). Here, each of the stations is permitted to contact any other station they wish without permission from the NCS

9. Networks (Nets)
MRL 47
MRH 67
Free Net
Free Network
MRK 17
MRK 92

10. Networks (Nets) Directed Net
To communicate with another station you must have permission of the NCS
The NCS will do most of the communicating
Directed Network
8. On a Directed Net, stations may only communicate with the prior permission of the NCS who will dictate priorities and orders. This means that NCS will do most of the communicating as they will be the first point for any message.

11. Directed Networks (Nets) MRL 47 MRH 67 MRV 92 MRK 17 MRK 92 NCS
All messages must be sent with the permission of the NCS in this case MRV 92
MRK 17
MRK 92

12. Networks (Nets) Air Cadet Radio Nets
Enable you to learn and practice procedures
Techniques are based on allied military procedures
Assist with our activities and safety
Do not use non-standard procedures
9. The Air Cadet radio network has been established to encourage Cadets to learn and practice the art of radio communication using radio techniques based on the Allied Military radio procedures. Used correctly, the information and instructions transmitted can be of vital importance in assisting in the safe and successful operation of your activities. However, the use of non-standard procedures and phraseology could cause misunderstanding with potentially dangerous consequences. In addition to this, the Services must always be aware that a potential enemy may be able to receive the transmitted information, and use it to their advantage.

13. Radio Station A Radio Station is the smallest part of a Net
It will have at least one radio set
The set will be able to transmit and receive
The set is known as a transceiver
10. From this you can see that the radio station is the smallest part of any radio network. The station will have at least one radio set capable of transmitting and receiving and which is generally known as a transceiver

14. HF Base Station for long distance
Radio Station
HF Base Station for long distance

15. Radio Station Similar procedures are used for:
High Frequency (HF) used for long range
Very High and Ultra High Frequencies used for short range
Directed Nets are more suited for HF
11. This first chapter has explained, in simple terms how an HF Net operates. Similar procedures can be used when using Very High Frequencies or Ultra High Frequencies (VHF/UHF) equipments and the rest of this book will be based around VHF/UHF equipments.

16. Operating from a remote location
VHF Communications
Operating from a remote location

17. Radio Spectrum Air Cadet Frequencies are:
Assigned by the Ministry of Defence
Are in the following bands:
Medium Frequency (MF)
High Frequency (HF)
Very High Frequency (VHF)
Ultra High Frequency (UHF)
Radio Spectrum
Frequencies
12. The Air Cadet Organisation has a number of frequencies assigned to them by the Ministry of Defence. These frequencies are in the Medium, High, Very High and Ultra High parts of the Radio Spectrum.

18. Radio Spectrum Medium (MF) High (HF) Very High (VHF) Ultra High (UHF)
300Khz to
3Mhz
3MHz
30Mhz
30MHz
300MHz To
3GHz
13. The Radio Spectrum is broken down into frequency bands and the chart below shows the breakdown:
Medium High Very High Ultra High
300Khz 3MHz 30MHz 300MHz
to to to to
3MHz 30MHz 300MHz 3GHz
Only the part of the spectrum where the Air cadets use frequencies is shown. There are frequency bands either side of those shown but you do not require knowledge of these for this course.
In simplistic terms: Lower the Frequency Longer the Range
Higher the Frequency Shorter the Range
Long Range
Short Range

19. Any questions?