Basic Radio Communications
August 2011
Objectives:
• Describe the different types of radio equipment used in the
ATC
• Describe how radio equipment’s operational frequency can
limit its use
• Outline the link between aerials and the range of radio
transmissions
• Describe the features of an Air Cadet radio network that
enable sending messages
• Use the phonetic alphabet to spell words and convey figures
in radio messages
• Use Radio Procedures to make radio checks
• Explain the safe care and handling of radio batteries
• Show correct safety procedures when using radio eqipment
Base Station
•
•
•
•
Mains Powered
Usually fixed at local HQ
Range typically over 50 km
External aerial usually raised above
a building
Mobile Radio
•Powered from the vehicle’s battery
•Range typically 25km +
•Uses external antenna fitted to
vehicle body
Portable Radio
•Range typically 5km+
•Has replaceable rechargeable
battery
•Fitted with its own antenna
Frequency Bands
• Typically the Air Cadet Organisation uses 3
bands of equipment, which are part of the
electromagnetic spectrum.
They are:
• UHF (Ultra High Frequency)
• VHF (Very High Frequency
• HF (High Frequency
• Air Cadet radios operate on different
frequencies of electromagnetic radiation.
• Generally, the higher the operating
frequency, the lower the range of the
transmission
• Higher frequencies have the benefit of
shorter range but better readability
• Lower frequencies have greater ranger
but are more subject to interference
The Electromagnetic (radio wave) Spectrum
ATC
Directional Aerials
A BEAM aerial used for concentrating transmission and
reception of radio signals in a particular direction giving
potentially greater range
You will sometimes see these on the roofs of homes from
when they were used to receive earlier TV transmissions
Omni-directional Aerials
•Radiate and receive Radio Frequency radiation equally in all
directions
•Usually fitted to portable and mobile radio installations
Ideally an aerial – or Antenna- should be
‘matched’ to the operating frequency of the
equipment being used.
The higher the frequency in use, the smaller
the aerial
• UHF Handheld radio
• HF Base Station
Directed Network
• A directed net is always “CONTROLLED” by a
Network Control Station (NCS).
Directed Network
Level of control depends on:
•
•
•
The level of radio discipline being observed
by those using the network.
Using proper procedures.
The type of network being operated.
Directed Network
•
•
Only one station
can be the NCS.
The NCS is usually
a fixed base
station, located in
a room specifically
for radio
communications.
MRW51
MRW48
MRW34
MRW37
Free Network
•On a Free Network all
stations are allowed to
communicate with each
other without requiring
permission from a NCS
MRW51
MRW48
MRW34
MRW37
The Phonetic Alphabet
Alpha
Beta
Charlie
Delta
Echo
Foxtrot
Golf
Hotel
India
Juliet
Kilo
Lima
Mike
November
Oscar
Papa
Quebec
Romeo
Sierra
Tango
Uniform
Victor
Whisky
X-Ray
Yankee
Zulu
You should be able to spell your name and classification using the phonetic
alphabet
For example:
John Smith would be spoken as:
Juliet Oscar Hotel November SPACE Sierra Mike India Tango Hotel
Signal Strength
• The strength of a signal is divided into five
levels or degrees. They are:
• Loud (the strongest)
• Good
• Weak
• Very weak
• Fading (the weakest)
Readability
Readability is the capacity of understanding.
There are six grades or degrees of readability:
• Clear
• Readable
• Unreadable
• Distorted
• Intermittent
• Interference
Radio Checks
• Radio checks are made to establish comms
with another station before passing a
message. A typical Radio Check is made as
follows:
• Hello MRT 65, this is MRK95. Radio check,
Over
• MRK95 this is MRT65, you are loud clear, Over.
• MRT65 this is MRK95, Loud Readable, OUT.
So a response to a radio check could comprise
combinations of strength and readability.
For example:
•
•
•
•
Loud Clear
Loud Readable
Weak Clear
Very weak Distorted
Demonstrate the safe care and
handling of radio batteries
Never
• Carry loose batteries in pockets or bags
• Short (directly connect) the terminals together
Always
• Cover battery terminals when in transit or not in use
• Charge with the correct type of charger (if in doubt, ASK).
Show correct safety procedures when
using portable radio equipment
• Never use a handheld portable radio when
driving, riding a bicycle or climbing a tree.
• Keep the conversation as short as possible.
• Keep the radio antenna away from the face as
far as possible.
• Ensure that batteries are correctly inserted.
• Switch off after use.