At our February meeting, SPARC’s vice president Jeff Liter, W2JCL gave a presentation on extra features available within APRS (the Automatic Packet Reporting System). These features are called gateway services because they are managed through computer gateways that transmit data over APRS.
WXBot is a service which sends you weather data on request. By messaging specific commands to WXBot, you can control what information the service sends back.
With APRS to SMS you can send a message to someone’s phone even when you are out of cell range. APRS carries your message via radio to a gateway and then out to the internet for delivery. In order to send a message via this gateway successfully, your recipient must opt in at the site linked above.
There are also gateway services which allow you to communicate with WhatsApp, spot yourself for SOTA activations, send short emails, or interact with your Winlink account. However, Jeff warned that the Winlink service is not user friendly.
Gateway services must use the national APRS frequency of 144.390 and transmit via AX.25 packet as opposed to protocols like VARA FM. They are run by volunteers, and many provide donation links so users can help cover the cost of their operation.
To access APRS, you need a 2m radio and a way to interface that radio with a laptop, phone, or tablet. Jeff demonstrated PinPoint APRS running on his Windows laptop with SoundModem, a software TNC. On iOS, the most common app to use is APRS.fi, and on Android it is APRSDroid.
Laptops typically require an external sound card connecting the radio and the computer. Jeff recommended the compact offerings from DigiRig for both laptop and phone/tablet use. He demonstrated an iPad running APRS.fi which only required an audio connection to the radio because the app handled the TNC function by itself.
Below are the slides from Jeff’s presentation.