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) SpectrumATC

Directional Aerials

A BEAM aerial used for concentrating transmission and reception of radio signals in a particular direction giving potentially greater rangeYou 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. MRW34 MRW37

MRW51

MRW48

Free Network

MRW34 MRW37

MRW51

MRW48

•On a Free Network all stations are allowed to communicate with each other without requiring permission from a NCS

The Phonetic AlphabetAlpha 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 alphabetFor 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.