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