Using APRSDroid in AFSK mode, you can transmit data through a radio station in APRS mode.
I experimented with two BAOFENG radio stations and bring APRSDroid settings.

Settings - parameters

• call sign - your call sign, for example R1bjk
• ssid - 15 "General additional stations" or other SSID ("Narrow Station", "Moving Station"). If two radio stations are used with your call sign, their SSID should vary. For example, -7 and -15.
• APRS Path - empty
• connection parameters:
  • Protocoling of the connection - VCL
  • Connection protocol - sound (AFSK)
  • High -quality decoder - vkl
  • Audio output - voice call
  • prefix of the synchronization of the frame - 400
• APRS Symbol - ANY
• Voice frequency - gap
• Comment - space
• location installations - enter the coordinates
  • Coordinates source - enter the coordinates of
  • Latences: 0
  • longitude: 0
  • Automatic sending \* - Turned off the minimum update time - 60 minutes (does not affect, because the sending of the coordinates is off)
• Privacy of location - 4 (DD*) (does not affect, because the sending of the coordinates is turned off)
• transmit speed & course - off
• transmit height - off
• Keep the screen on - off
• Notifications
  • incoming messages: flashing LED, vibration
  • Notifications - their own location packages - everything is turned off

*Seling to enable the “Automatic Sending” option, the radio station will transfer the coordinates to the air every hour (or every n minutes indicated in the parameter “Minimum update time”). Thus, you can turn on the APRS-beacon in parallel with the APRS pager. But various options using the GPS receiver ("Smartbeaconing", "send periodically through the interval" or fakegps) lead to more frequent dispersal of coordinates, which leads to a significant category of radio battery, and the search for satellites discharges the smartphone. In the article I consider the option of transmission according to messages as necessary, in the Pager mode. In this mode, the radio station goes to the transfer only when entering and sending messages by the radio amateur - the operator of the radio station .

Usage

To start communicating with APRS, you need to transfer at least one bag. Then another station will be able to answer the APRS package.

Для начала обмена, один из операторов должен один раз передать местоположение. Которое может иметь широту и долготу 0.0 / 0.0. Нажатие кнопки "Отправить местоположение" при включенном VOX переведет радиостанцию на передачу и обозначит Вас в эфире, и у других корреспондентов появится возможность ответа на вызов нажатием на строку Вашего позывного сигнала.

To listen to the broadcast through the cable from the radio station and analyzing incoming gears (reception) and transmission capabilities, both radio stations and smartphone with APRSDroid should be in the cordinate tracking mode (the button "start tracking" ). Information on the air is transmitted only in tracking mode, when the APRS service operates in the smartphone. On the screen should be burned by the inscription "Ste the tracking".

APRS premises are sent using a pop -up “message” menu, which appears with prolonged holding the finger at the call sign. The maximum message length is 43 characters (in the ASCII encoding, letters 0-9, symbols, A-Z, A-Z). Read more APRS messages described in the PDF document https://www.aprs.org/doc/aprs101.pdf в разделе "8 POSITION AND DF REPORT DATA FORMATS".

КабAPRS spruce and smartphone are called APRS-K1. Sold on AliExpress and Ozon. (Search by keywords "Cable for APRS").