Overview of APRS Timeslot and Channel Analysis

APRS RF channels are limited resources that are shared by many radio stations. Also, because of the Carrier Sense Multiple Access/Collision Detection (CSMA/CD) aspects of the protocol, the channel cannot normally be used beyond 50 percent of its theoretical capacity due to collisions, and usually less than that due to other issues such as "hidden transmitter" and transmit-only trackers. The timeslot analysis plugin provides tools for analyzing the loading of the channel.

The analysis looks at when traffic is transmitted by the various stations heard on the radio interfaces, and determines how much locally-hearable channel capacity is being used, both directly and by digipeats of the traffic. This can be seen either as a statistical table or as a color-coded series of timelines showing at what exact time periods the channel was busy. Such analysis should be performed over at least a 30 minute interval, as that is the slowest "cycle time" recommended for periodic packet transmissions; the interval can be configured, but in practice will only be as long as data is collected in YAAC.