Radio communications are the the most commonly used means of communication today. It is the easiest to use and the most versatile. It requires no particular skill and it has tremendous range. In addition, it supports a multitude of types of communication, ie telephony (voice), telegraphy (morse), facsimile (reproduction of original documents or graphics at the recipient), video (television), and data (computer to computer). It is not susceptible to some of the shortcomings the other methods have, ie day/night, weather, restricted visibility, etc). Because of the speed at which the system works (300 000 kilometres per second)it can handle large volumes of traffic. The down side is that there is no privacy and anyone with a receiver is able to listen in on conversations. To obtain privacy and to protect the content of messages, the transmissions have to be encrypted. Another downside is the fact that vessels can be located by interception and triangulation of transmissions by others such as pirates or the enemy during wartime.

The advantages of using radio are:

1. Radio is capable of world wide ranges.
2. It is a very rapid means of passing signals.
3. Because of its speed radio can handle large volumes of traffic.
4. It can transmit a variety of modes of communication ie Voice telephony, morse telegraphy, computer to computer data, facsimile, video.
5. It is not dependent on the state of weather, visibility or time of day/night.
6. Users of radio do not have to have any special skill to operate.

The disadvantages are:

1. Radios require electricity to operate.
2. Obviously they are more expensive than the other means.
3. They provide no privacy unless the circuit is protected by encryption.
4. They are “noisy” electronically and during wartime and other special circumstances (piracy) it gives the enemy/opposition the ability to intercept signals and with direction finding gear to locate the transmitter.

Radio procedures.
What is the procedure followed when sending a message by radio-telephony?
Firstly there are four components to each message:

• The call (identity of the station called).
• The identity of the caller.
• The message (text).
• The ending.

When the calling ship establishes communication, it will carry out the following:

• The call, ie ”STARLING” (ship’s name) or” RTVF” (callsign)
• The identity, ie “this is FIREDANCE” (ship’s name) or “this is DEMF”( callsign)
• “Over” (ending, asking the other ship to reply).

The called ship will reply as follows:

• The call, “FIREDANCE” or “DEMF”
• The identity, “this is STARLING” or “RTVF”
• “Over” (ending, telling the other ship that it is standing by to receive its message)

The calling ship will answer in turn as follows:

• “This is FIREDANCE” (abbreviated call)
• “Message” (the message is sent)
• Over. (ending, telling the other ship to acknowledge receipt or reply)

Let us say that the message does not require an answer other than an acknowledgement of receipt.
The receiving ship acknowledges as follows:

• “This is STARLING” (abbreviated call)
• “Roger” (Yes or I acknowledge receipt)
• “Out” (Ending, telling the other ship that it does not require a reply or further communication)

Sometimes on radio and TV dramas when the actors are speaking on a radio circuit one hears the expression “over and out”. This is obviously ignorance of proper voice procedure. Basically what the individual is saying is “answer, don’t answer”, which is ridiculous. It can only be “over” or “out”!

Fixed radio transceiver with hand held microphone.

Portable hand-held radios.