How APRS works

A radio or tracker creates a short digital packet and transmits it over radio. The packet may contain a callsign, position, speed, course, comment or other information.

Information can be displayed immediately on a map or on the screen of an APRS-capable radio.

Digipeaters

A digipeater receives an APRS packet and retransmits it over radio. This extends the coverage of mobile and low-power stations beyond direct radio range.

Packet paths and relay counts must be limited to avoid overloading the shared radio channel.

IGate and APRS-IS

An IGate receives APRS packets from radio and forwards them to the international APRS-IS internet network.

This makes stations visible on internet maps. Some IGates can also transmit permitted messages from APRS-IS back into their local radio area.

What APRS can carry

• positions of mobile and fixed stations;
• short text messages;
• weather reports;
• equipment telemetry;
• map objects and events;
• repeater and local service information.

APRS Narva

APRS Narva provides a local map of stations, objects and tracks in Narva and Ida-Virumaa.

The map receives data both from the international APRS-IS network and through APRS Narva's own server. This makes it possible to display amateur-radio activity and local communication infrastructure in the region.

Practical uses

• tracking mobile stations;
• events and exercises;
• volunteer coordination;
• reporting locations of groups and objects;
• weather and equipment monitoring;
• backup short-message communication.

Limitations

APRS uses a shared, low-capacity radio channel. Excessive beacon rates, long paths and unnecessary retransmissions can interfere with other users.

APRS does not replace official emergency services, and delivery of every packet cannot be guaranteed.