ARRL

Chapter Two: Principles of NTS Operation

Chapter Two: Principles of NTS Operation

The National Traffic System includes four different net levels which operate in an orderly time sequence to effect a definite flow pattern for traffic from origin to destination. A message flows through the National Traffic System in a manner similar to an airline passenger who starts out in a small residential town with a destination across the continent in another small town. He has to change carriers many times in the process, starting with a local ground conveyance to a feeder airline, to a transcontinental airline, to another feeder airline, then local transportation to deliver him to his destination. In a very similar manner, the transcontinental message starts with the originating station in a local net, is carried to the section net, the region net, the area net, via Transcontinental Corps (TCC) to a distant area net and then back down the line to delivery.

Of course the message, like the passenger, can "get on" or "get off" at any point if that's the origin or destination. Thus, a message from, say, New York to Detroit would never get on TCC, but would "get off" at area level. A message from San Francisco to Los Angeles would not go beyond region level, and one from Syracuse to Buffalo would remain inside the section net.

Messages may also be passed through NTS-affiliated local and section traffic nodes that employ digital modes with store-and-forward capabilities and bulletin board operations. Long hauls can be made by NTS Digital Relay Stations at HF, that interface with Section traffic nodes, and the traditional nets of the system.

Figure 3, organization chart for the evening cycle four NTS setup in the Central Area.

2.1 Local Nets

Local nets are those which cover small areas such as a community, city, county or metropolitan area, not a complete ARRL section. They usually operate by VHF (typically 2-meter FM) at times and on days most convenient to their members; some are designated as "emergency" (ARES) nets that do not specialize in traffic handling. The time slot designated for them is thus nominal and will vary considerably. Local nets are intended mainly for local delivery of traffic, inasmuch as such delivery could ordinarily be effected conveniently by non-toll telephone. Some NTS local nets operate on a daily basis, just as do other nets of the system, to provide outlets for locally-originated traffic and to route the incoming traffic as closely as possible to its actual destination before delivery -- a matter of practice in a procedure that might be required in an emergency.

Most local nets and even some section nets in smaller sections use repeaters to excellent effect. Average coverage on VHF can be extended tenfold or more using a strategically located repeater, and this can achieve a local coverage area wide enough to encompass many of the smaller sections. Since propagation conditions on the high frequencies are erratic, more use of VHF and repeaters is recommended at local levels.

A local net or node may also be conducted on a local packet BBS, where radiograms may be stored, forwarded and picked up by local operators for delivery. A Net (Node) Manager is appointed by the Section Traffic Manager to manage these functions, and assure that traffic is moved expeditiously in accordance with basic NTS principles, just like their counterpart nets on local repeaters.

2.2 Section Nets

Organizational and procedural lines begin to tighten at the section net level. Coverage of the section may be accomplished either by individual stations reporting in, by representatives of NTS local nets and nodes, or both. Ordinarily, all section amateurs are invited to take part; however, in a high-population section with several metropolitan areas covered by local nets, representation may be by such liaison stations plus individual stations in cities or towns not covered by local nets.

The section may have more than one net (a CW net, a VHF net, an SSB net  or even a section packet BBS, for examples), or two or more sections may combine to form a single net operating at section level, if low population or activity seem to make this desirable. Section nets are administered through the office of the Section Manager, with authority for this function often delegated to an appointed Section Traffic Manager and/or designated Net Managers.

In the case of combined-section nets, officials of the sections concerned should collaborate on the designation of a qualified amateur to manage the net. The purpose of the section net is to handle intra-section traffic, distribute traffic coming down from higher NTS echelons and put inter-section traffic in the hands of the amateur designated to report into the next-higher NTS (region) echelon. Therefore, the maximum obtainable participation from section amateurs is desirable.

2.3 Region Nets

Region nets cover a wider area, such as a call area. At this level the object is no longer mass coverage, but representation of each ARRL section within the region.

Participants normally include:

  1. A net control station, designated by the region net manager.
  2. Representatives from each of the various sections in the region, designated by their section net managers.
  3. One or more stations designated by the region net manager to handle traffic going to points outside the region.
  4. One or more stations bringing traffic down from higher NTS echelons.
  5. Any other station with traffic.

There may be more than one representative from each section in the region net, but more than two are usually superfluous and will only clutter the net; however, all section representatives are required to represent the entire section, not just their own net.

The purpose of the region net is to exchange traffic among the sections in the region, put out-of-region traffic in the hands of stations designated to handle it and distribute traffic coming to the region from outside among the section representatives. Region nets are administered by managers who are elected by NTS Area Staff members.

2.4 Area Nets

At the top level of NTS nets is the area net. In general, the area net is to the region net what the region net is to the section net; that is, participation at area level includes:

  1. A net control station, designated by the area net manager.
  2. One or more representatives from each region net in the area, designated by the region net managers.
  3. TCC stations designated to handle traffic going to other areas.
  4. TCC stations designated to bring traffic from other areas.
  5. Any station with traffic.

Points (3) and (4) are functions of the Transcontinental Corps. There are three areas, designated Eastern, Central and Pacific, the names roughly indicating their coverage of the U.S. and Canada, except that the Pacific Area includes the Mountain as well as the Pacific time zones. Area nets are administered by managers who are elected by NTS Area Staff members.

 

2.5 Transcontinental Corps

The handling of inter-area traffic is accomplished through the facilities of the TCC. This is not a net, but a group of designated stations who have the responsibility for seeing that inter-area traffic reaches its destination area. TCC is administered by TCC directors, or as delegated to the Area Digital Coordinator, in each area who assign stations to report into area nets for the purpose of "clearing" inter-area traffic, and to keep out-of-net schedules with each other for the purpose of transferring traffic from one area to another.

2.6 Digital Stations

The handling of traffic among sections, regions and areas can also be accomplished alternatively, on a supportive/cooperative basis, through liaison with the traditional aspects of the system, by the set of NTS Digital Relay Stations across the country. These stations, certified by their respective Area Digital Coordinators, handle traffic by digital modes at HF. The system structure is more loosely defined than is the traditional system. They serve to supplement the existing system, providing options, and flexibility in getting traffic moved expeditiously across the country, especially in overload conditions.

Figure 4, NTS organization chart.