SUMTER COUNTY
Amateur Radio Emergency Services Association (ARES)

 Sumter County, Florida

EMComm Tools

There are several digital tools that provide additional capabilities to the Radio Operator.


APRS  The automatic packet reporting system is an amateur radio-based system for real time tactical digital communications of information of immediate value in the local area.   APRS data is typically broadcast on a single shared frequency to be repeated locally by area relay stations and digipeaters for widespread local consumption.  In addition, all such data is typically ingested into the APRS Internet System (APRS-IS) via an internet connected receiver (igate) and distributed globally.  Shared information contains global coordinates, altitude, speed, heading, text messages, alerts, announcements, and bulletins. 

The most visible aspect of APRS is its capability of map display.  Anyone may place any object or information on the map, and it is distributed to all maps of all users in the local RF network or to anyone monitoring the area via the Internet.  Any station, radio, cell phone, or object broadcasting GPS coordinates to the APRS system can be automatically tracked over time. 

Other prominent map features are weather stations, alerts, and objects.

In the most widely used form, APRS is transported over the AX .25 protocol using 1200 bits per second on frequencies located within the North American Two-Meter Band.   Typically, the software is used for mobile exercises where each radio operator is at a separate location and may be stationary or moving. All of this information is used by the NCS for dispatching the nearest radio operator to an incident.


Winlink  Winlink, also known as the Winlink 2000 Network, is a global email system using the radio that mixes internet technology and appropriate amateur radio radio frequency (RF) technologies. The system provides radio interconnection services including: email with attachments, position reporting, graphic and text weather bulletins, emergency relief communications, and message relay. The system is built and administered by volunteers without pecuniary interests. Winlink 2000 is a project of the Amateur Radio Safety Foundation, Inc. (ARSFI)


FlDigi  Fldigi, the Fast Light Digital modem application is a free and open-source program which allows an ordinary computer's sound card to be sued as a simple two-way data modem.  The software is mostly used by amateur radio operations who connect the microphone and headphone connections of an amateur radio Single-Side-Band transceiver or an FM two way radio to the computer's headphone and microphone connections.  The interconnection creates a "soundcard defined radio" whose available bandwidth is limited by the soundcard's sample rate and the external radio's bandwidth.

Such communications are normally done on the shortwave amateur radio bands in modes such as PSK31, RTTY, Olivia, and CW (Morse Code) .  Increasingly the software is also being used on VHF and UHF frequencies.

Fldigi software is also used for amateur radio emergency communications when other communication systems fail due to natural disaster or power outages.  Transfer of small files, emails, and IC forms are possible using the radio with free computer software.

 Last Update:  09/15/2016    Copyright Sumter County ARES. All Rights Reserved.