During an emergency communication situation, a high volume of disorganized messages can quickly turn an overloaded communication system into a disaster of its own. To prevent this from happening, Amateur Radio operators use regular protocols called a “network” or “net” to organize the flow of messages. The mission of the net is to effectively move as much traffic as accurately and quickly as possible. Nets can be either formal or informal, as needs dictate. Nets can be conducted via voice, Morse code, or digital modes, depending on the situation.
Anatomy of Net Operations
The Net Manager is the person in charge of a net and is most often not the person who conducts the net on the air. Net Managers ensure that there is a Net Control Station (NCS) with enough operators for each shift, and monitor net and band conditions to see if changes in frequency are needed. If more than one net is operating, a Net Manager may be responsible for a group of nets.
The Net Manager coordinates the various nets and their Net Control Stations to ensure a smooth flow of traffic within and between nets. Net Managers may assign various human and equipment resources to meet the needs of each net.
Net Managers may be responsible for a regularly scheduled net, or they may be temporarily appointed to manage one or more ad hoc nets created for a particular emergency incident.
A Net Control Station directs the minute-by-minute operation of the net on the air. The NCS controls the flow of messages according to priority and keeps track of where messages come from and where they go, as well as any that have yet to be sent. They also keep a current list of which stations are where, their assignments, and their capabilities. In a busy situation, the NCS may have one or more assistants to help with record-keeping.
Liaison stations handle messages that need to be passed from one net to another. The NCS or Net Manager may assign one or more stations to act as liaisons between two specific nets. These stations can monitor one or both nets, depending on resources. It is easier to monitor only one net at a time. This can be accomplished by having one station in each net assigned as the liaison to the other, or by having a single liaison station check into both nets on a regular schedule. In the event that an “emergency” precedence message needs to be passed to another net when the liaison is not monitoring that net, any net member can be assigned to jump to the other net and pass the message.
Learning proper NCS technique and handling such duties is one of the most important functions in emergency communications. During an emergency or disaster, the first operator to arrive on frequency is the NCS operator — at least until a Net Manager or a leadership official arrives on frequency to take control and perhaps to assign someone else to be the NCS.
Net Types
Open (Informal) Nets
During an open emergency net, there is minimal central control by a Net Control Station, if indeed there is an NCS at all. Stations call one another directly to pass messages. Unnecessary chatter is usually kept to a minimum. Open nets are often used during the period leading up to a potential emergency and as an operation winds down, or in smaller nets with only a few stations participating.
Directed (Formal) Nets
A directed emergency net is created whenever large numbers of stations are participating, or where the volume of traffic cannot be dealt with on a first-come, first-served basis. In a communication emergency of any size, it is usually best to operate a directed net. In such situations, the NCS can prioritize traffic by nature and content.
In a directed net, the NCS controls all net operations. Check-ins may not interrupt the net or transmit unless specifically instructed to do so by the NCS, or unless they have an emergency message. The NCS will determine who uses the frequency and which traffic will be passed first. Casual conversation is strongly discouraged, and tactical call signs or tactical designators will probably be used.
Recap
Any list of the major strengths of Amateur Radio in an emergency setting includes our abilities to share information in a “group setting” in real time across multiple locations and even multiple served agencies. Unlike many other types of communications, our radio messages can be heard by everyone in the group at once — and they can respond. This gives flexibility to emergency response managers, which is very useful.